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How to define the selected item (not selected item) in the combo box?

First, a fair warning: I'm a complete newbie with C # and WPF.

I have a combobox (editable, searchable) and I would like to be able to grab the Delete key and remove the currently selected item from the list. The behavior I'm looking for is similar to the behavior of MS Outlook when entering email addresses. When you give a few characters, a drop-down list of potential matches is displayed. If you go to one of them (using the arrow keys) and click "Delete", this entry will be permanently deleted. I want to do this with an entry in the combo box.

Here is the XAML (simplified):


<ComboBox x:Name="Directory"
    KeyUp="Directory_KeyUp"
    IsTextSearchEnabled="True"
    IsEditable="True"
    Text="{Binding Path=CurrentDirectory, Mode=TwoWay}"
    ItemsSource="{Binding Source={x:Static self:Properties.Settings.Default}, 
        Path=DirectoryList, Mode=TwoWay}" />

Handler:


private void Directory_KeyUp(object sender, KeyEventArgs e)
{
    ComboBox box = sender as ComboBox;
    if (box.IsDropDownOpen &&  (e.Key == Key.Delete))
    {
        TrimCombobox("DirectoryList", box.HighlightedItem);  // won't compile!
    }
}

, box.HighlightedItem , , , :

System.Windows.Controls.ComboBox' does not contain a definition for 'HighlightedItem'...

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+5
4

Highlighted Item Non-Public, .

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, Reflection, . SO : - ReflectionAttribute

+2

, . HighlightedItem, , , GetType().GetProperty().GetValue()

private void Directory_KeyUp(object sender, KeyEventArgs e)
{
    ComboBox box = sender as ComboBox;
    if (box.IsDropDownOpen && (e.Key == Key.Delete))
    {
        const BindingFlags flags = BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance;
        PropertyInfo hl = box.GetType().GetProperty("HighlightedItem", flags);
        if (hl != null)
        {
            String hlString = hl.GetValue(sender, null) as String;
            // TODO: remove from DirectoryList
        }
    }
}
+7

DrawItem DrawItemState.Selected( ).

void Main()
{
    Application.Run(new Form1());
}

public partial class Form1 : Form
{
    ComboBox ComboBox1;
    string[] ds = new string[]{"Foo", "Bar", "Baz"};

    public Form1 ()
    {
        InitializeComboBox();
    }

    private void InitializeComboBox()
    {
        ComboBox1 = new ComboBox();

        ComboBox1.DataSource = ds;
        Controls.Add(ComboBox1);

        ComboBox1.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawVariable;
        ComboBox1.DrawItem += new DrawItemEventHandler(ComboBox1_DrawItem);
    }

    private void ComboBox1_DrawItem(object sender, DrawItemEventArgs e)
    {
        e.DrawBackground();
        e.Graphics.DrawString(ds[e.Index],ComboBox1.Font,Brushes.Black,e.Bounds);

        if (e.State == DrawItemState.Selected)
        {
            //stores the "HighlightedIndex" in the control tag field.  Change as you see fit.
            ComboBox1.Tag = e.Index; 
            //Console.WriteLine(e.Index);
        }
    }
}
0

The definition of System.Windows.Controls.ComboBox does not contain a property HighlightedItem- this is why you are not compiling the code.

Are you using the combo box from System.Windows.Controls.ComboBox? Then just cast it to the appropriate type.

Late note: If you want to catch the highlighted ComboBox event, read this link - it solves exactly this problem.

-1
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