Imports System.Data.SqlClient
Public Class Form1
' Your database connection string
Dim connectionString As String = "YourConnectionStringHere"
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
' Populate the ComboBox with data on form load
PopulateComboBox()
End Sub
Private Sub PopulateComboBox()
' Your SQL query to retrieve distinct values for the ComboBox
Dim query As String = "SELECT DISTINCT YourColumnName FROM YourTableName"
' Create a SqlConnection
Using connection As New SqlConnection(connectionString)
' Open the connection
connection.Open()
' Create a SqlCommand
Using command As New SqlCommand(query, connection)
' Create a SqlDataReader to read data
Using reader As SqlDataReader = command.ExecuteReader()
' Clear existing items in the ComboBox
comboBox1.Items.Clear()
' Add items to the ComboBox
While reader.Read()
comboBox1.Items.Add(reader("YourColumnName").ToString())
End While
End Using
End Using
End Using
End Sub
Private Sub comboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles comboBox1.SelectedIndexChanged
' Clear existing items in the CheckBoxList
checkBoxList1.Items.Clear()
' Check if an item is selected in the ComboBox
If comboBox1.SelectedItem IsNot Nothing Then
' Get the selected value from the ComboBox
Dim selectedValue As String = comboBox1.SelectedItem.ToString()
' Call a method to populate the CheckBoxList based on the selected value
PopulateCheckBoxList(selectedValue)
End If
End Sub
Private Sub PopulateCheckBoxList(selectedValue As String)
' Your SQL query to retrieve values for the CheckBoxList based on the selected value
Dim query As String = "SELECT YourCheckBoxListColumnName FROM YourTableName WHERE YourComboBoxColumnName = @SelectedValue"
' Create a SqlConnection
Using connection As New SqlConnection(connectionString)
' Open the connection
connection.Open()
' Create a SqlCommand with parameters
Using command As New SqlCommand(query, connection)
' Add parameters
command.Parameters.AddWithValue("@SelectedValue", selectedValue)
' Create a SqlDataReader to read data
Using reader As SqlDataReader = command.ExecuteReader()
' Add items to the CheckBoxList
While reader.Read()
checkBoxList1.Items.Add(reader("YourCheckBoxListColumnName").ToString())
End While
End Using
End Using
End Using
End Sub
End Class