Question

I have a simple TextBox with the Style “AutoCompleteTextBox”:

<TextBox Name="TextBox" Style="{StaticResource AutoCompleteTextBox}" />

The Style is located in my Resource Dictionary:

<Style x:Key="AutoCompleteTextBox" TargetType="{x:Type TextBox}">
    <Setter Property="KeyboardNavigation.TabNavigation" Value="None" />
    <Setter Property="FocusVisualStyle" Value="{x:Null}" />
    <Setter Property="AllowDrop" Value="true" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type TextBox}">
                <Grid>
                    <Border x:Name="Bd" SnapsToDevicePixels="true">
                        <ScrollViewer x:Name="PART_ContentHost" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                    </Border>
                    <Popup x:Name="PART_Popup" StaysOpen="False" Placement="Bottom" IsOpen="False">
                        <ListBox x:Name="PART_ListBox" HorizontalContentAlignment="Stretch"/>
                    </Popup>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

In my Code Behind File I have two getters:

private Popup Popup
{
    get { return Template.FindName("PART_Popup", this) as Popup; }
}
private ListBox ItemList
{
    get { return Template.FindName("PART_ListBox", this) as ListBox; }
}

and the textbox load event:

void TextBox_Loaded(object sender, RoutedEventArgs e)
{
    var popup = Popup;

    var itemlist = ItemList;
}

Now I have the problem that Popup and ItemList returns always null, why?

Answer 1

In XAML you create a normal TextBox and style it, in code behind you have this.Template & this, how is that supposed to work? There is no way that this is actually the TextBox.