wpf ListBox控件：简单的GetSelectedValue / item-value

Question

List box is not binded just a Combobox replacement (values are exposed)

Xaml

  <ListBox SelectionChanged="LBX_AddTaskOptions_SelectionChanged"  HorizontalAlignment="Left" Margin="19,29,0,0" Name="LBX_AddTaskOptions" VerticalAlignment="Top" Width="125" FontWeight="Bold" Background="Beige">
                        <ListBoxItem Background="Beige" FontWeight="Bold" v>
                            <StackPanel Orientation="Horizontal">
                                <TextBlock Text="internet"></TextBlock>
                                <Image Source="Images\IE_BlackRed.png" Height="30"></Image>
                            </StackPanel>
                        </ListBoxItem>
                        <ListBoxItem Background="Beige" FontWeight="Bold">
                            <StackPanel Orientation="Horizontal">
                                <TextBlock Text="localFolder"></TextBlock>
                                <Image Source="Images\Folder_Black.png" Height="30"></Image>
                            </StackPanel>
                        </ListBoxItem>
                    </ListBox>

CodeBehind

    private void LBX_AddTaskOptions_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        var SelItm = LBX_AddTaskOptions.SelectedItem.ToString();

        MessageBox.Show(Sel);

    }

i have searched for that question, though answers are only for complex issues as i am fresh .net Developer, i know all methods to extract DDL text/value i even made extentions , though couldn't figure how to do this simple value extraction

shouldn't it be simple ?

messageBox shows the name of control (:

Answer 1

This isn't quite the right approach for XAML. You don't want to list out the markup for each item -- instead, use an ItemTemplate to define how it should look, and use bindings to render the actual item:

<ListBox SelectionChanged="LBX_AddTaskOptions_SelectionChanged" Name="LBX_AddTaskOptions">
    <ListBox.ItemTemplate>
        <ListBoxItem Background="Beige" FontWeight="Bold" v>
            <StackPanel Orientation="Horizontal">
                <TextBlock Text="{Binding}" />
                <Image Source="Images\IE_BlackRed.png" Height="30" />
            </StackPanel>
        </ListBoxItem>
    </ListBox.ItemTemplate>
</ListBox>

Bind the ListBox ItemsSource to the model data itself (ie, the array of strings in this case). Now, eventually you'll probably want to use a view model, but you can also add the items from code behind on load:

string[] ListBoxItems = new string[] { "internet", "local folder" };
LBX_AddTaskOptions.ItemsSource = ListBoxItems;

This should result in SelectedValue giving you the correct value.

---

_{Footnote -- you could get the selected value using the markup you've written out in the question -- but it would be ugly and would defeat the whole purpose of XAML. You'd need to cast SelectedItem to a ListBoxItem , then get its child and cast that to a StackPanel, get its children, etc, you get the idea. And then, of course, if the markup changes at all, the code you just wrote is no longer valid.}

Answer 2

The item that you are getting in your selected value is a ListBoxItem with a control inside it. If you want to extract the value like the text then you have to do this

private void LBX_AddTaskOptions_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    var SelItm = LBX_AddTaskOptions.SelectedItem as ListBoxItem;
        var StackPanel = SelItm.Content as StackPanel;
        foreach (var child in StackPanel.Children)
        {
            if(child is TextBlock)
            {
                MessageBox.Show((child as TextBlock).Text);
            }
        }

}

You have to sort of dig into the control to get the actual text. There are a lot of ways to get the value but this is the pretty basic one.

Calling ToString() method will just convert the current object as a string which is a ListBoxItem.