Hung Blog Docs

1. Đầu tiên, mình lấy serial number của HDD. Vì serial number HDD là duy nhất, nên ứng dụng mình cài vào máy tính nào thì chỉ sử dụng được một máy, cài đặt vào ổ cứng khác thì ứng dụng sẽ không hoạt động.
2. Tạo khóa token (chuỗi bảo mật).
3. Sử dụng thuật toán SHA1, serial number HDD với token của mình. Bạn có thể sử dụng thuật toán MD5, hay 1 thuật toán mã hóa bất kỳ.

Giao diện ứng dụng:

wmic diskdrive get serialnumber

Chúng ta bắt đầu Import thư viện.

Imports System.ComponentModel
Imports System.Text
Imports System.Security.Cryptography
Imports System.Management
Imports System.Data
Imports System.Data.SqlClient

Tiếp theo là hàm lấy Serial number HDD.

 Public Function GetDriveSerialNumber() As String
            Dim hdd As New ManagementObjectSearcher("select * from Win32_DiskDrive")
            Dim hd As ManagementObject
            For Each hd In hdd.Get()
                HDD_Serial = hd("SerialNumber")

            Next
            Return HDD_Serial
 End Function

Tiếp tục hàm mã hóa SHA1.

Public Function SHA1(ByVal number As String) As String
            Dim ASCIIENC As New ASCIIEncoding
            Dim strreturn As String
            strreturn = vbNullString
            Dim bytesourcetxt() As Byte = ASCIIENC.GetBytes(number)
            Dim SHA1Hash As New SHA1CryptoServiceProvider
            Dim bytehash() As Byte = SHA1Hash.ComputeHash(bytesourcetxt)
            For Each b As Byte In bytehash
                strreturn &= b.ToString("X8")
            Next
            Return strreturn
End Function

Viết hàm tạo key license cho software

 Private Sub btnCreateKey_Click(sender As Object, e As EventArgs) Handles btnCreateKey.Click
            Dim key As String
            key = SHA1(serialHDD.Trim & token)
            txtLicenseKey.Text = key
End Sub

Viết hàm đăng ký license cho ứng dụng.

Private Sub SimpleButton1_Click(sender As Object, e As EventArgs) Handles SimpleButton1.Click
            Dim keyLicense As String = txtRegister.Text
            Dim key As String
            key = SHA1(serialHDD.Trim & token)
            If (keyLicense = key) Then
                saveData("update license set licensekey='" & keyLicense & "' where id=1")
                Me.Hide()
                Dim frm As New XtraForm1
                frm.ShowDialog()
            Else
                MessageBox.Show("Key is not Valid!", "ERROR!")
            End If
End Sub

Viết hàm kiểm tra khi chạy ứng dụng, ứng dụng đã được đăng ký hay chưa

 Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
            lblserialHDD.Text = GetDriveSerialNumber().Trim()
            'get serial key from data
            Dim keyData As String
            keyData = getData()
            'get key from hdd serial with token sha1
            Dim key As String
            key = SHA1(serialHDD.Trim & token)
            If keyData = key Then
                Me.Hide()
                Dim frm As New XtraForm1
                frm.ShowDialog()
            End If
End Sub

VIDEO DEMO ỨNG DỤNG

Lập trình hướng đối tượng (OOP)

Phát triển ứng dụng nhanh (RAD)

[DEVEXPRESS] Tạo month picker trên DateEdit Winform C#

1. Chọn ngày tháng trong các biểu đồ và lịch trình.
2. Hiển thị các sự kiện hoặc hoạt động được lên kế hoạch trong tương lai.
3. Chọn các khoảng thời gian trong các báo cáo hoặc thống kê.
4. Lọc dữ liệu theo tháng hoặc năm trong các bảng dữ liệu.
5. Đặt ngày hết hạn hoặc ngày kết thúc cho các tác vụ hoặc dự án.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading;
using System.Windows.Forms;

namespace MonthPickerDevexpress
{
    public partial class Form1 : DevExpress.XtraEditors.XtraForm
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Thread.CurrentThread.CurrentCulture = new System.Globalization.CultureInfo("en-US");
            var monthnames = new string[] { "Tháng 1", "Tháng 2", "Tháng 3", "04", "05", "06", "07", "08", "09", "10", "11","12", "" };
            Thread.CurrentThread.CurrentCulture.DateTimeFormat.AbbreviatedMonthNames = monthnames;
            Thread.CurrentThread.CurrentCulture.DateTimeFormat.MonthGenitiveNames = monthnames;

            dateEdit1.Properties.EditMask = "MM/yyyy";
            dateEdit1.Properties.UseMaskAsDisplayFormat = true;
            dateEdit1.Properties.VistaCalendarViewStyle = DevExpress.XtraEditors.VistaCalendarViewStyle.YearView;
            dateEdit1.Properties.CalendarView = DevExpress.XtraEditors.Repository.CalendarView.TouchUI;
        }
    }
}

DOWNLOAD SOURCE CODE

* Giao diện chương trình giải mã:

- Cú pháp để giải mã:

$hash = "5f4dcc3b5aa765d61d8327deb882cf99";
$hash_type = "md5";
$email = "exemple@test.com";
$code = "0123456789";
$reponse = file_get_contents("http://md5decrypt.net/Api/api.php?hash=".$hash."&hash_type=".$hash_type."&email=".$email."&code=".$code);
echo $reponse;

Public Class Form1
    Private Sub btnDecrypt_Click(sender As Object, e As EventArgs) Handles btnDecrypt.Click
        Dim email As String = "hung.pro.vn@gmail.com"
        Dim token As String = "499a6997b538e3c9"
        Dim hash As String = txtInput.Text
        Dim hashType As String = cboType.Text

        Dim url As String = "http://md5decrypt.net/Api/api.php?hash=" & hash & "&hash_type=" & hashType & "&email=" & email & "&code=" & token
        WebBrowser1.Navigate(url)
    End Sub
End Class

II. Tiến hành thôi

using Excel = Microsoft.Office.Interop.Excel;

// Khởi động chtr Excell
Excel.Application exApp = new Excel.Application();
 
// Thêm file temp xls
Excel.Workbook exBook = exApp.Workbooks.Add(
          Excel.XlWBATemplate.xlWBATWorksheet );
 
// Lấy sheet 1.
Excel.Worksheet exSheet = (Excel.Worksheet)exBook.Worksheets[1];

string workbookPath = "c:/SomeWorkBook.xls";
 
COMExcel.Workbook exBook = exApp.Workbooks.Open(workbookPath,
        0, false, 5, "", "", false, Excel.XlPlatform.xlWindows, "",
        true, false, 0, true, false, false);

exSheet.Name = "hung.pro.vn";

// Range là ô [1,1] (A1)
COMExcel.Range r = (COMExcel.Range) exSheet.Cells[1, 1];
 
// Ghi dữ liệu
r.Value2 = "Demo excel value";
 
// Giãn cột
r.Columns.AutoFit();
 
// Hiển thị chương trình excel
exApp.Visible = true;
 
// Đóng chương trình excel
Console.WriteLine("Đợi file Excel chạy");
Console.ReadLine();
exApp.Quit();

COMExcel.Range r = (COMExcel.Range)exSheet.get_Range("A1", "A4");
r.Value2 = "My Value";            
r.Columns.AutoFit();

// Ẩn chương trình
exApp.Visible = false;    
 
// Save file
exBook.SaveAs("C:\\file.xls", COMExcel.XlFileFormat.xlWorkbookNormal,
                null,null,false,false,
                COMExcel.XlSaveAsAccessMode.xlExclusive,
                false,false,false,false,false);
exApp.Quit();

exBook.Close(false, false, false);
exApp.Quit();
System.Runtime.InteropServices.Marshal.ReleaseComObject(exBook);
System.Runtime.InteropServices.Marshal.ReleaseComObject(exApp);

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
 
using System.Threading;
using Excel;
 
 
 
namespace Ghi_du_lieu_Excel
{
    class Program
    {
        static void Main(string[] args)
        {
            Excel.Application exApp = new Excel.Application();
 
            Excel.Workbook exBook = exApp.Workbooks.Add(
            Excel.XlWBATemplate.xlWBATWorksheet);
 
            // Lấy sheet 1.
            Excel.Worksheet exSheet = (Excel.Worksheet)exBook.Worksheets[1];
            exSheet.Name = "Arduino.vn";
            // Range là ô [1,1] (A1)
            Excel.Range a = (Excel.Range)exSheet.Cells[1, 1];
            Excel.Range t = (Excel.Range)exSheet.Cells[2, 1];
 
            // Ghi dữ liệu
            a.Value2 = "Cộng đồng Arduino";
            t.Value2 = "Đỗ Hữu Toàn";
 
            // Giãn cột
            a.Columns.AutoFit();
            Console.WriteLine("Đang chạy file Excel lên");
            // Hiển thị chương trình excel
            exApp.Visible = true;  
            Thread.Sleep(5000);
            // Ẩn chương trình
            exApp.Visible = false;
 
            // Save file
            exBook.SaveAs("E:\\file.xls", Excel.XlFileFormat.xlWorkbookNormal,
                            null, null, false, false,
                            Excel.XlSaveAsAccessMode.xlExclusive,
                            false, false, false, false, false);
 
            exBook.Close(false, false, false);
            exApp.Quit();
            System.Runtime.InteropServices.Marshal.ReleaseComObject(exBook);
        }
    }
}

III. Lời kết

I. Thiết kế giao diện chính và trang trí

II. Code

Form1:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
// Thêm 3 em này vào là OK, để sài SerialPort
using System.IO;
using System.IO.Ports;
using System.Xml;

using System.Threading;// khởi tạo hàm Threading

namespace nhandulieuCOM
{
    public partial class Form1 : Form
    {
        string InputData = String.Empty; // Khai báo string buff dùng cho hiển thị dữ liệu sau này.
        delegate void SetTextCallback(string text); // Khai bao delegate SetTextCallBack voi tham so string
        public Form1()
        {
        //cái Thread thực ra để chạy Form3 khi ms zô...cho ngầu
            Thread t = new Thread(new ThreadStart(SplashScreen));//tạo 1 Thread t là SplashScreen
            t.Start();// khi chương trình bật thỳ chạy t...tức là gọi SplashScreen
            Thread.Sleep(4500);//ngủ 4,5s  
            InitializeComponent();
            t.Abort();//sau đó đóng t
            // Khai báo hàm delegate bằng phương thức DataReceived của Object SerialPort;
            // Cái này khi có sự kiện nhận dữ liệu sẽ nhảy đến phương thức DataReceive
            // Nếu ko hiểu đoạn này bạn có thể tìm hiểu về Delegate, còn ko cứ COPY . Ko cần quan tâm
            serialPort1.DataReceived += new SerialDataReceivedEventHandler(DataReceive);
            string[] BaudRate = { "1200", "2400", "4800", "9600", "19200", "38400", "57600", "115200" };
            comboBox2.Items.AddRange(BaudRate);// Thiết lập cho comboBox2
        }
        private void SplashScreen()
        {
            Application.Run(new Form3());//chạy Form3
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            comboBox1.DataSource = SerialPort.GetPortNames();
            comboBox2.SelectedIndex = 3;
        }







        private void timer1_Tick(object sender, EventArgs e)
        {
            if (!serialPort1.IsOpen)
            {
                button2.Enabled = true;
                button1.Enabled = false;
                Thongbao.Text = ("Bạn chưa kết nối, hãy chọn một cổng COM để kết nối nhé!!! keke !! Arduino.vn");
                Thongbao.ForeColor = Color.Red;
            }
            else if (serialPort1.IsOpen)
            {
                button2.Enabled = false;
                button1.Enabled = true;
                Thongbao.Text = ("Đã kết nối nhé!!! keke");
                Thongbao.ForeColor = Color.Green;

            }
        }
        private void DataReceive(object obj, SerialDataReceivedEventArgs e)
        {
            InputData = serialPort1.ReadExisting();
            if (InputData != String.Empty)
            {
                // txtIn.Text = InputData; // Ko dùng đc như thế này vì khác threads .
                SetText(InputData); // Chính vì vậy phải sử dụng ủy quyền tại đây. Gọi delegate đã khai báo trước đó.
            }

        }
        // Hàm của em nó là ở đây. Đừng hỏi vì sao lại thế.
        private void SetText(string text)
        {
            if (this.textBox1.InvokeRequired)
            {
                SetTextCallback d = new SetTextCallback(SetText); // khởi tạo 1 delegate mới gọi đến SetText
                this.Invoke(d, new object[] { text });
            }
            else this.textBox1.Text += text;
        }

        private void button2_Click(object sender, EventArgs e)
        {
            if (!serialPort1.IsOpen)
            {
                serialPort1.PortName = comboBox1.Text;
                serialPort1.BaudRate = Convert.ToInt32(comboBox2.Text);
                serialPort1.Open();
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            serialPort1.Close();
        }

        private void button5_Click(object sender, EventArgs e)
        {
        // Hiện tí thông báo..cho ngầu
            if (serialPort1.IsOpen)// đã kết nối thì
            {
            //nếu chưa nhập
                if (textBox2.Text == "") MessageBox.Show("Nhập dữ liệu cần gửi vào nhé!!!", "Đỗ Hữu Toàn - Thông báo");
                else

                    serialPort1.Write(textBox2.Text);// ngược lại...gửi giá trị từ textBox tới cổng COM
            }
            // Nếu cổng COM chưa kết nối
            else MessageBox.Show("Kết nối cổng COM đi bạn", "Đỗ Hữu Toàn - Thông báo");
            textBox2.Clear();


            }

        private void button3_Click(object sender, EventArgs e)
        {
            textBox2.Clear();
            textBox1.Clear();
            //Ấn xóa clear hết textbox
        }

        private void button4_Click(object sender, EventArgs e)
        {
            DialogResult stt = MessageBox.Show("Bạn chắc chắn muốn thoát chương trình???", "Đỗ Hữu Toàn - Arduino.vn", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
            if (stt == DialogResult.Yes ) MessageBox.Show("Cảm ơn bạn đã sử dụng chương trình, nhớ Rate Note ủng hộ mình nhé","Đỗ Hữu Toàn - Arduino.vn");
            Close();
        }

        

        private void linkLabel1_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
        {
            Form2 tacgia = new Form2();
            tacgia.ShowDialog();
            // chạy form2 khi ấn nút tác giả ( linklabel1)
        }

        
        
     }
}

Form 2:

(chỉ là phần logo..k cóa code nhé)

Form 3:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace nhandulieuCOM
{
    public partial class Form3 : Form
    {
        public Form3()
        {
            InitializeComponent();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            //Khi timer làm tươi...tăng 1 đơn vị cho progessBar
            progressBar1.Increment(1);
            if(progressBar1.Value == 100)
            {
            // Nếu ProgessBar = 100..Tức là Max r đó
                timer1.Stop();// thì sop timer..ngừng làm tươi..ngừng tăng processBar
            }

        }
    }
}

III. Kết quả

[VB.NET] CRUD Thêm xóa sửa tìm kiếm Realtime FireBase

Dưới đây là giao diện demo ứng dụng:

Imports FireSharp.Config
Imports FireSharp.Response
Imports FireSharp.Interfaces

Imports System.Web.Script.Serialization '(Importing System.Web.Script.Serialization) This is used to read and convert JSON strings.
Imports System.ComponentModel '(Importing System.ComponentModel) This is used to sort data on DataGridView.
Imports System.IO '(Importing System.IO) This is used for ImageToBase64 Public Functions and Base64ToImage Public Functions.
Public Class Form1
    Dim IMG_FileNameInput As String 'This variable is used to hold the address and file name of the image that will be displayed in the registration section.
    Dim clearDGVCol As Boolean = True
    Private dtTableGrd As DataTable 'This variable is used to search data on DataGridView.

    '-------------------------------------------Configure FireSharp
    Private fcon As New FirebaseConfig() With
        {
            .AuthSecret = "afojSxW25t6PgEl98qmLSanufOI3jKkGG552XaoW",
            .BasePath = "https://laptrinhvb-c96be.firebaseio.com/"
        }

    Private client As IFirebaseClient
    '-------------------------------------------

    Public Function ImageToBase64(image As Image) As String
        Using ms As New MemoryStream()
            ' Convert Image to byte[]  
            Dim Format As System.Drawing.Imaging.ImageFormat = Imaging.ImageFormat.Jpeg
            image.Save(ms, Format)
            Dim imageBytes As Byte() = ms.ToArray()

            ' Convert byte[] to Base64 String  
            Dim base64String As String = Convert.ToBase64String(imageBytes)
            Return base64String
        End Using
    End Function


    Public Function Base64ToImage(base64String As String) As Image
        ' Convert Base64 String to byte[]  
        Dim imageBytes As Byte() = Convert.FromBase64String(base64String)
        Dim ms As New MemoryStream(imageBytes, 0, imageBytes.Length)

        ' Convert byte[] to Image  
        ms.Write(imageBytes, 0, imageBytes.Length)
        Dim image__1 As Image = System.Drawing.Image.FromStream(ms, True)
        Return image__1
    End Function
    '-------------------------------------------
    Sub DisplayRegSave(Stat As Boolean)
        TBName.Enabled = Stat
        TBID.Enabled = Stat
        CBGender.Enabled = Stat
        CBGender.Enabled = Stat
        BtnSave.Enabled = Stat
        BtnClearAll.Enabled = Stat
    End Sub

    Sub DisplayRecLoad(Stat As Boolean)
        TBSearch.Enabled = Stat
        CBSearchBy.Enabled = Stat
        BtnEdit.Enabled = Stat
        BtnDelete.Enabled = Stat
        BtnRefresh.Enabled = Stat
        BtnClearSelection.Enabled = Stat
        DGVUserData.Enabled = Stat
    End Sub
    '-------------------------------------------

    '-------------------------------------------Sub to load data from database and display in DataGridView.
    Sub ShowRecord()
        Try
            Dim dtTable As New DataTable
            dtTable.Columns.Add("Name")
            dtTable.Columns.Add("ID")
            dtTable.Columns.Add("Gender")
            dtTable.Columns.Add("City")
            dtTable.Columns.Add("Image", GetType(Image))

            '-------------------------------------------Conditions for deleting columns. This was executed only once.
            If clearDGVCol = True Then
                DGVUserData.Columns.Clear()
                clearDGVCol = False
            End If
            '-------------------------------------------

            Dim SRRecord = client.Get("PersonDB/") 'To load and hold Database in JSON file format.

            '-------------------------------------------To converts the specified JSON string to an object of type T.
            '-------------------------------------------For more information see here : 
            '-------------------------------------------https://docs.microsoft.com/en-us/dotnet/api/system.web.script.serialization.javascriptserializer.deserialize?view=netframework-4.8
            Dim myJsonTool As New JavaScriptSerializer
            Dim myDeserializedItems = myJsonTool.Deserialize(Of Dictionary(Of String, PersonalData))(SRRecord.Body)
            '-------------------------------------------

            '-------------------------------------------To enter a Database (in JSON file format that has been previously converted into an object form) into a Table.
            For Each dictItem As KeyValuePair(Of String, PersonalData) In myDeserializedItems
                dtTable.Rows.Add(dictItem.Value.Name,
                                 dictItem.Value.ID,
                                 dictItem.Value.Gender,
                                 dictItem.Value.City,
                                 Base64ToImage(dictItem.Value.Image))
            Next
            '-------------------------------------------

            DGVUserData.DataSource = dtTable 'Gets or sets the data source that the DataGridView is displaying data for.
            dtTableGrd = dtTable 'Entering data from dtTable into dtTableGrd, dtTableGrd is used to find data and display it on DataGridView.

            Dim imageColumn = DirectCast(DGVUserData.Columns("Image"), DataGridViewImageColumn)
            imageColumn.ImageLayout = DataGridViewImageCellLayout.Zoom
            '-------------------------------------------

            DGVUserData.Sort(DGVUserData.Columns(0), ListSortDirection.Ascending)

            LblTotalUser.Text = "Total Users : " & DGVUserData.RowCount

            Me.Text = "VB Net Firebase RealTime Database"
            LabelRecordView.Text = "Record View"
            DisplayRecLoad(True)

            DGVUserData.ClearSelection()
        Catch ex As Exception
            If ex.Message = "One or more errors occurred." Then
                MessageBox.Show("Cannot connect to firebase, check your network !", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
            ElseIf ex.Message = "Object reference not set to an instance of an object." Then
                Dim dtTable As New DataTable
                dtTable.Columns.Add("Name")
                dtTable.Columns.Add("ID")
                dtTable.Columns.Add("Gender")
                dtTable.Columns.Add("City")
                dtTable.Columns.Add("Image", GetType(Image))
                DGVUserData.DataSource = dtTable
                MessageBox.Show("Database not found or Database is empty.", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information)
            Else
                MessageBox.Show(ex.Message, "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
            End If

            Me.Text = "VB Net Firebase RealTime Database"
            LabelRecordView.Text = "Record View"
            DisplayRecLoad(True)
        End Try
    End Sub
    '-------------------------------------------
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Try

            client = New FireSharp.FirebaseClient(fcon)
            BtnRefresh_Click(sender, e)
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try

        CBSearchBy.SelectedIndex = 0
    End Sub

    Private Sub BtnCreateID_Click(sender As Object, e As EventArgs) Handles BtnCreateID.Click
        Try
            TBID.Text = "Please wait..."

            Dim r As Random = New Random
            Dim num As Integer
            num = (r.Next(1, 99999))
            Dim IDresults As String = Strings.Right("00000" & num.ToString(), 5)

            Dim Check_ID = client.Get("PersonDB/" + IDresults)

            '-------------------------------------------Conditions to check whether the ID has been used.
            If Check_ID.Body <> "null" Then
                MessageBox.Show("The same ID is found, create another ID by pressing the Create ID button.", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Else
                TBID.Text = IDresults
            End If
            '-------------------------------------------
        Catch ex As Exception
            If ex.Message = "One or more errors occurred." Then
                TBID.Clear()
                MessageBox.Show("Cannot connect to firebase, check your network !", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Else
                TBID.Clear()
                MessageBox.Show(ex.Message, "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
            End If
        End Try
    End Sub

    Private Sub BtnSave_Click(sender As Object, e As EventArgs) Handles BtnSave.Click
        If BtnSave.Text = "Save" Then 'Conditions for storing data to the database.
            If TBName.Text = Nothing Then
                MessageBox.Show("Name field is empty." & vbCrLf & "Please fill in the name field to continue.", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                Return
            End If

            If TBID.Text = Nothing Then
                MessageBox.Show("ID field is empty." & vbCrLf & "Please fill in the name field to continue.", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                Return
            End If

            If CBGender.Text = Nothing Then
                MessageBox.Show("Gender field is empty." & vbCrLf & "Please fill in the name field to continue.", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                Return
            End If

            If TBCity.Text = Nothing Then
                MessageBox.Show("City field is empty." & vbCrLf & "Please fill in the name field to continue.", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                Return
            End If

            If IMG_FileNameInput = Nothing Then
                MessageBox.Show("Image file has not been entered." & vbCrLf & "Please enter the image to continue.", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                Return
            End If

            Try
                Me.Text = "VB Net Firebase RealTime Database (Saving. Please wait...)"
                LabelRegistration.Text = "Registration (Saving. Please wait...)"
                DisplayRegSave(False)

                Dim ImgData As String = ImageToBase64(PictureBoxUserReg.Image)

                Dim PD As New PersonalData() With
                    {
                    .Name = TBName.Text,
                    .ID = TBID.Text,
                    .Gender = CBGender.Text,
                    .City = TBCity.Text,
                    .Image = ImgData
                    }

                Dim save = client.Set("PersonDB/" + TBID.Text, PD) 'To save data to Firebase Database.

                DisplayRegSave(True)
                LabelRegistration.Text = "Registration"
                Me.Text = "VB Net Firebase RealTime Database"

                MessageBox.Show("Data saved successfully.", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information)

                BtnClearAll_Click(sender, e)
                BtnRefresh_Click(sender, e)
            Catch ex As Exception
                If ex.Message = "One or more errors occurred." Then
                    MessageBox.Show("Cannot connect to firebase, check your network !", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                Else
                    MessageBox.Show(ex.Message, "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                End If

                DisplayRegSave(True)
                LabelRegistration.Text = "Registration"
                Me.Text = "VB Net Firebase RealTime Database"
            End Try

        Else 'Conditions for updating data to a database.

            If TBName.Text = Nothing Then
                MessageBox.Show("Name field is empty." & vbCrLf & "Please fill in the name field to continue.", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                Return
            End If

            If TBCity.Text = Nothing Then
                MessageBox.Show("City field is empty." & vbCrLf & "Please fill in the name field to continue.", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                Return
            End If

            Try
                Me.Text = "VB Net Firebase RealTime Database (Updating. Please wait...)"
                LabelRegistration.Text = "Registration (Updating. Please wait...)"
                DisplayRegSave(False)

                Dim ImgData As String = ImageToBase64(PictureBoxUserReg.Image)

                Dim PD As New PersonalData() With
                    {
                    .Name = TBName.Text,
                    .ID = TBID.Text,
                    .Gender = CBGender.Text,
                    .City = TBCity.Text,
                    .Image = ImgData
                    }

                Dim update = client.Update("PersonDB/" + TBID.Text, PD) 'To update data to Firebase Database.

                DisplayRegSave(True)
                LabelRegistration.Text = "Registration"
                Me.Text = "VB Net Firebase RealTime Database"

                MessageBox.Show("Data updated successfully.", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information)

                BtnClearAll_Click(sender, e)
                BtnRefresh_Click(sender, e)
            Catch ex As Exception
                If ex.Message = "One or more errors occurred." Then
                    MessageBox.Show("Cannot connect to firebase, check your network !", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                Else
                    MessageBox.Show(ex.Message, "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                End If

                DisplayRegSave(True)
                LabelRegistration.Text = "Registration"
                Me.Text = "VB Net Firebase RealTime Database"
            End Try
        End If
    End Sub

    Private Sub PictureBoxUserReg_Click(sender As Object, e As EventArgs)

        OpenFileDialogUserImage.FileName = ""
        OpenFileDialogUserImage.Filter = "JPEG (*.jpeg;*.jpg)|*.jpeg;*.jpg"

        If (OpenFileDialogUserImage.ShowDialog(Me) = System.Windows.Forms.DialogResult.OK) Then
            IMG_FileNameInput = OpenFileDialogUserImage.FileName
            PictureBoxUserReg.ImageLocation = IMG_FileNameInput
        End If
    End Sub

    Private Sub BtnClearAll_Click(sender As Object, e As EventArgs) Handles BtnClearAll.Click
        TBName.Clear()
        TBID.Clear()
        CBGender.Text = Nothing
        TBCity.Clear()
        PictureBoxUserReg.Image = My.Resources.avatar
        IMG_FileNameInput = Nothing
        BtnSave.Text = "Save"
        BtnCreateID.Enabled = True
    End Sub

    Private Sub BtnRefresh_Click(sender As Object, e As EventArgs) Handles BtnRefresh.Click
        Me.Text = "VB Net Firebase RealTime Database (Loading. Please wait...)"
        LabelRecordView.Text = "Record View (Loading. Please wait...)"
        DisplayRecLoad(False)
        ShowRecord()
    End Sub

    Private Sub BtnEdit_Click(sender As Object, e As EventArgs) Handles BtnEdit.Click
        '-------------------------------------------The condition to check whether the data to be edited has been selected in DataGridView
        If DGVUserData.SelectedRows.Count = 0 Then
            MessageBox.Show("Please select one row in the table to edit.", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Return
        End If
        '-------------------------------------------

        '-------------------------------------------Conditions to check whether there is more than one data selected on DataGridView.
        If DGVUserData.SelectedRows.Count > 1 Then
            MessageBox.Show("You select " & DGVUserData.SelectedRows.Count & " rows in the Table." & vbCrLf & "The Edit feature can only edit one row in a table.", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Return
        End If
        '-------------------------------------------

        If DGVUserData.SelectedRows.Count = 1 Then
            TBName.Text = DGVUserData.SelectedRows(0).Cells("Name").Value
            TBID.Text = DGVUserData.SelectedRows(0).Cells("ID").Value
            CBGender.Text = DGVUserData.SelectedRows(0).Cells("Gender").Value
            TBCity.Text = DGVUserData.SelectedRows(0).Cells("City").Value
            PictureBoxUserReg.Image = DGVUserData.Rows(DGVUserData.SelectedRows(0).Index).Cells("Image").Value
            BtnSave.Text = "Update"
        End If
    End Sub

    Private Sub BtnDelete_Click(sender As Object, e As EventArgs) Handles BtnDelete.Click
        '-------------------------------------------Conditions for deleting all data in the database.
        If AllCellsSelected(DGVUserData) = True Then
            Try
                If MsgBox("Are you sure you want to delete all data ?", MsgBoxStyle.Question + MsgBoxStyle.OkCancel, "Confirmation") = MsgBoxResult.Cancel Then Return

                Me.Text = "VB Net Firebase RealTime Database (Deleting. Please wait...)"
                LabelRecordView.Text = "Record View (Deleting. Please wait...)"
                DisplayRecLoad(False)

                Dim deleteAll = client.Delete("PersonDB") 'To delete data in the Firebase Database

                MessageBox.Show("Data successfully deleted.", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information)

                Me.Text = "VB Net Firebase RealTime Database"
                LabelRecordView.Text = "Record View"
                DisplayRecLoad(True)

                BtnRefresh_Click(sender, e)
                Return
            Catch ex As Exception
                If ex.Message = "One or more errors occurred." Then
                    MessageBox.Show("Cannot connect to firebase, check your network !", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                Else
                    MessageBox.Show(ex.Message, "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                End If

                Me.Text = "VB Net Firebase RealTime Database"
                LabelRecordView.Text = "Record View"
                DisplayRecLoad(True)
            End Try
        End If
        '-------------------------------------------

        '-------------------------------------------Conditions for deleting one data or several data in the Database.
        Try
            If DGVUserData.SelectedRows.Count = 0 Then
                MessageBox.Show("Please select one row or several rows to be deleted.", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
                Return
            End If

            If MsgBox("Are you sure you want to delete this data ?", MsgBoxStyle.Question + MsgBoxStyle.OkCancel, "Confirmation") = MsgBoxResult.Cancel Then Return

            Me.Text = "VB Net Firebase RealTime Database (Deleting. Please wait...)"
            LabelRecordView.Text = "Record View (Deleting. Please wait...)"
            DisplayRecLoad(False)

            For Each row As DataGridViewRow In DGVUserData.SelectedRows
                If row.Selected = True Then
                    Dim delete = client.Delete("PersonDB/" & row.DataBoundItem(1).ToString)
                End If
            Next

            MessageBox.Show("Data successfully deleted.", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information)

            Me.Text = "VB Net Firebase RealTime Database"
            LabelRecordView.Text = "Record View"
            DisplayRecLoad(True)

            BtnRefresh_Click(sender, e)
        Catch ex As Exception
            If ex.Message = "One or more errors occurred." Then
                MessageBox.Show("Cannot connect to firebase, check your network !", "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Else
                MessageBox.Show(ex.Message, "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error)
            End If

            Me.Text = "VB Net Firebase RealTime Database"
            LabelRecordView.Text = "Record View"
            DisplayRecLoad(True)
        End Try
        '-------------------------------------------
    End Sub
    Private Function AllCellsSelected(dgv As DataGridView) As Boolean
        If dgv.RowCount = 0 Then
            AllCellsSelected = False
            Return AllCellsSelected
        End If
        AllCellsSelected = (dgv.SelectedCells.Count = (dgv.RowCount * dgv.Columns.GetColumnCount(DataGridViewElementStates.Visible)))
        If dgv.RowCount = 1 Then
            AllCellsSelected = False
        End If
    End Function

    Private Sub BtnClearSelection_Click(sender As Object, e As EventArgs) Handles BtnClearSelection.Click

        DGVUserData.ClearSelection()
    End Sub

    Private Sub TBSearch_TextChanged(sender As Object, e As EventArgs)
        'dtTableGrd.DefaultView.RowFilter = CBSearchBy.Text & " Like '" & TBSearch.Text & "%'" 'To search for data on the DataGridView
        DGVUserData.ClearSelection()
    End Sub

    Private Sub EditToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles EditToolStripMenuItem.Click

        BtnEdit_Click(sender, e)
    End Sub

    Private Sub DeleteToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles DeleteToolStripMenuItem.Click

        BtnDelete_Click(sender, e)
    End Sub

    Private Sub SelectAllToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles SelectAllToolStripMenuItem.Click

        DGVUserData.SelectAll()
    End Sub

    Private Sub ClearSelectionToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ClearSelectionToolStripMenuItem.Click

        BtnClearSelection_Click(sender, e)
    End Sub

    Private Sub TBSearch_TextChanged_1(sender As Object, e As EventArgs) Handles TBSearch.TextChanged
        dtTableGrd.DefaultView.RowFilter = CBSearchBy.Text & " Like '" & TBSearch.Text & "%'" 'To search for data on the DataGridView
        DGVUserData.ClearSelection()
    End Sub

    Private Sub PictureBoxUserReg_Click_1(sender As Object, e As EventArgs) Handles PictureBoxUserReg.Click
        OpenFileDialogUserImage.FileName = ""
        OpenFileDialogUserImage.Filter = "JPEG (*.jpeg;*.jpg)|*.jpeg;*.jpg"

        If (OpenFileDialogUserImage.ShowDialog(Me) = System.Windows.Forms.DialogResult.OK) Then
            IMG_FileNameInput = OpenFileDialogUserImage.FileName
            PictureBoxUserReg.ImageLocation = IMG_FileNameInput
        End If
    End Sub
End Class

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1. Hệ nhị phân là gì?

2. Hệ thập phân là gì?

3. Hệ thập lục phân là gì?

Giao diện demo ứng dụng VB.NET:

SOURCE CODE CONVERT BIN, DEC, HEX VB.NET

Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim Strconvert As String = TextBox1.Text
        Dim Decimals As Integer
        Dim hexadecimal As String
        Dim Binary As String
        Dim x As Integer

        ' convert Binary to Binary
        If ComboBox1.Text = "Binary" And ComboBox2.Text = "Binary" Then
            TextBox2.Text = TextBox1.Text
            ' convert Binary to Decimal
        ElseIf ComboBox1.Text = "Binary" And ComboBox2.Text = "Decimal"
            Decimals = Convert.ToInt32(Strconvert, 2)
            TextBox2.Text = Decimals.ToString
            ' convert Binary to Hexadecimal
        ElseIf ComboBox1.Text = "Binary" And ComboBox2.Text = "Hexadecimal"
            Decimals = Convert.ToInt32(Strconvert, 2)
            hexadecimal = Convert.ToString(Decimals, 16)
            TextBox2.Text = hexadecimal
            ' convert Decimal to Binary
        ElseIf ComboBox1.Text = "Decimal" And ComboBox2.Text = "Binary"
            x = Convert.ToInt32(Strconvert)
            Binary = Convert.ToString(x, 2)
            TextBox2.Text = Binary
            ' convert Decimal to Hexadecimal
        ElseIf ComboBox1.Text = "Decimal" And ComboBox2.Text = "Hexadecimal"
            x = Convert.ToInt32(Strconvert)
            hexadecimal = Convert.ToString(x, 16)
            TextBox2.Text = hexadecimal
            ' convert Hexadecimal to Binary
        ElseIf ComboBox1.Text = "Hexadecimal" And ComboBox2.Text = "Binary"
            Decimals = Convert.ToInt32(Strconvert, 16)
            Binary = Convert.ToString(Decimals, 2)
            TextBox2.Text = Binary
            ' convert Hexadecimal to Decimal
        ElseIf ComboBox1.Text = "Hexadecimal" And ComboBox2.Text = "Decimal"
            Decimals = Convert.ToInt32(Strconvert, 16)
            TextBox2.Text = Decimals.ToString
        Else
            If ComboBox1.Text = "Select Format" Or ComboBox2.Text = "Select Format" Or ComboBox1.Text = "" Or ComboBox2.Text = "" Then
                MsgBox("Please Insert Select type to convert")
            End If
        End If
    End Sub

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        ' Add items into ComboBox1
        ComboBox1.Items.Add("Binary")
        ComboBox1.Items.Add("Decimal")
        ComboBox1.Items.Add("Hexadecimal")
        ' Add items into ComboBox1
        ComboBox2.Items.Add("Binary")
        ComboBox2.Items.Add("Decimal")
        ComboBox2.Items.Add("Hexadecimal")
        ' Add Text into ComboBox1
        ComboBox1.Text = "Select Format"
        ' Add Text into ComboBox1
        ComboBox2.Text = "Select Format"
    End Sub
End Class

[VB.NET] Chia sẻ source code lịch âm dương và hẹn lịch nhắc việc

Video demo ứng dụng:

DOWNLOAD SOURCE CODE

[C#] Tự động show Popup các control như: Combobox, DateTimePicker

FULL CODE CSHARP:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace AutoShowPopupCombobox
{
    public partial class Form1 : Form
    {        
        [DllImport("user32.dll")]
        private static extern bool PostMessage(
        IntPtr hWnd, // handle to destination window
        Int32 msg, // message
        Int32 wParam, // first message parameter
        Int32 lParam // second message parameter
        );

        const Int32 WM_LBUTTONDOWN = 0x0201;
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            ShowPopupControl(comboBox1);
        }

        public void ShowPopupControl(Control control) {
            var x = control.Width - 10;
            var y = control.Height / 2;
            var lParam = x + y * 0x00010000;
            PostMessage(control.Handle, WM_LBUTTONDOWN, 1, lParam);
        }

        private void button2_Click(object sender, EventArgs e)
        {
            ShowPopupControl(dateTimePicker1);
        }

        private void btnclick_Click(object sender, EventArgs e)
        {
            ShowPopupControl(button4);
        }

        private void button4_Click(object sender, EventArgs e)
        {
            MessageBox.Show("Button 4 clicked!");
        }
    }
}

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