Handles ComboBox SelectionChanged events. : ComboBox « Windows Presentation Foundation « VB.Net Tutorial

1. VB.Net Tutorial
2. Windows Presentation Foundation
3. ComboBox

<Window x:Class="WpfApplication1.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="WPF" Height="100" Width="300">
    <StackPanel>
        <ComboBox Name="comboBox" IsEditable="True" Margin="5" SelectionChanged="ComboBox_SelectionChanged">
            <ComboBoxItem Content="ComboBox Item 1" Selected="ComboBoxItem_Selected" />
            <ComboBoxItem Content="ComboBox Item 2" Selected="ComboBoxItem_Selected" />
            <ComboBoxItem Content="ComboBox Item 3" Selected="ComboBoxItem_Selected" IsSelected="True"/>
            <ComboBoxItem Content="ComboBox Item 4" Selected="ComboBoxItem_Selected" />
            <ComboBoxItem Content="ComboBox Item 5" Selected="ComboBoxItem_Selected" />
        </ComboBox>
        <Button Content="Get Selected" Margin="5" Width="100" Click="Button_Click" />
    </StackPanel>
</Window>

//File:Window.xaml.vb
Imports System
Imports System.Windows
Imports System.Windows.Controls

Namespace WpfApplication1
  Public Partial Class Window1
    Inherits Window
    Public Sub New()
      InitializeComponent()
    End Sub
    Private Sub Button_Click(sender As Object, e As RoutedEventArgs)
      Dim item As ComboBoxItem = TryCast(comboBox.SelectedItem, ComboBoxItem)

      If item IsNot Nothing Then
        MessageBox.Show("Current item: " & Convert.ToString(item.Content), Title)
      ElseIf Not [String].IsNullOrEmpty(comboBox.Text) Then
        MessageBox.Show("Text entered: " + comboBox.Text, Title)
      End If
    End Sub

    Private Sub ComboBox_SelectionChanged(sender As Object, e As SelectionChangedEventArgs)

      If Not IsInitialized Then
        Return
      End If

      Dim item As ComboBoxItem = TryCast(comboBox.SelectedItem, ComboBoxItem)

      If item IsNot Nothing Then
        MessageBox.Show("Selected item: " & Convert.ToString(item.Content), Title)
      End If
    End Sub

    Private Sub ComboBoxItem_Selected(sender As Object, e As RoutedEventArgs)
      If Not IsInitialized Then
        Return
      End If

      Dim item As ComboBoxItem = TryCast(e.OriginalSource, ComboBoxItem)

      If item IsNot Nothing Then
        MessageBox.Show(Convert.ToString(item.Content) & " was selected.", Title)
      End If
    End Sub
  End Class
End Namespace

16.12.ComboBox
	16.12.1.	ComboBox Test
	16.12.2.	Bind ComboBox to ListBox ItemsSource
	16.12.3.	ComboBox with ComboBoxItem
	16.12.4.	Gets the currently selected ComboBoxItem when the user clicks the Button.
	16.12.5.	if the user has entered text into the ComboBox instead.
	16.12.6.	Handles ComboBox SelectionChanged events.
	16.12.7.	Handles ComboBoxItem Selected events.
	16.12.8.	View and Select Items Using a ComboBox