在 c# 中选择的项目为当前项目

Question

I have a list box which is bound to a collection in C# WPF. When I search for a record I want to move the selected item to the top of the list and mark as selected.

Here is my code:

var loc = lst_sub.Items.IndexOf(name);
lst_sub.SelectedIndex = loc;
lst_sub.Items.MoveCurrentToFirst();

Answer 1

This can be handled using a Behavior class...

public class perListBoxHelper : Behavior<ListBox>
{
    protected override void OnAttached()
    {
        base.OnAttached();
        AssociatedObject.SelectionChanged += AssociatedObject_SelectionChanged;
    }

    protected override void OnDetaching()
    {
        AssociatedObject.SelectionChanged -= AssociatedObject_SelectionChanged;
        base.OnDetaching();
    }

    private static void AssociatedObject_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        var listBox = sender as ListBox;

        if (listBox?.SelectedItem == null)
        {
            return;
        }

        Action action = () =>
        {
            listBox.UpdateLayout();

            if (listBox.SelectedItem == null)
            {
                return;
            }

            listBox.ScrollIntoView(listBox.SelectedItem);
        };

        listBox.Dispatcher.BeginInvoke(action, DispatcherPriority.ContextIdle);
    }
}

Usage...

<ListBox
    Width="200"
    Height="200"
    ItemsSource="{Binding Items}"
    SelectedItem="{Binding SelectedItem}">
    <i:Interaction.Behaviors>
        <vhelp:perListBoxHelper />
    </i:Interaction.Behaviors>
</ListBox>

More details on my blog post .