Question

I have a ListBox (WPF) and I am adding to it strings at runtime….
If I try to add string that is already exists in the ListBox it throws me an exception….. telling that this item is already in the ListBox….
How can I add the same strings to ListBox ?
Because I have situations in my application when I do have to add 2 identical strings….
thanks….

The ListBox –

<ListBox x:Name="listBox_MyListBox" Height="Auto" Width="Auto" Background="Transparent" MaxHeight="170" BorderThickness="0" Margin="3">
                        <ListBox.ItemTemplate>
                            <DataTemplate>
                                <TextBlock Margin="3" Padding="2" Text="{Binding}" TextAlignment="Center" FontSize="13"/>
                            </DataTemplate>
                        </ListBox.ItemTemplate>
                    </ListBox>

in the code behind I add the string like that –

 this.listBox_MyListBox.Items.Add(text.ToString());

Answer 1

Yes, you can add duplicate items to listbox, it allows without any issue
Example:

private void Window_Loaded ( object sender, RoutedEventArgs e )
{
   listBox_MyListBox.Items.Add ( "demo" );
   listBox_MyListBox.Items.Add ( "demo" );            
}

Note:
It would not let you add duplicate if you are using any of data sources which dont allow duplicate:
Dictionary or Hashtable may not allow duplicate entries, if that is the case with you then choose List or datatable as datasource