combo box inside a user control disappears when style is applied in wpf
I'm trying to apply a style to a combo box but instead of getting applied the combo box itself disappears. Please check the following xaml code for user control.
<UserControl
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:Microsoft_Windows_Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Luna"
x:Class="Guardian.PAS.PASFramework.UI.WPF.PASComboBox"
xmlns:local="clr-namespace:Guardian.PAS.PASFramework.UI.WPF"
Height="26" Width="100" VerticalAlignment="Center" >
<UserControl.Resources>
<Style x:Key="comboBoxStyle" TargetType="{x:Type local:PASCustomComboBox}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:PASCustomComboBox}">
<ControlTemplate.Triggers>
<Trigger Property="local:PASCustomComboBox.IsEnabled" Value="false">
<Setter Property="Background" Value="Red"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</UserControl.Resources>
<Canvas Name="canvas" Height="23" Width="Auto" VerticalAlignment="Center">
<Label Height="23" Name="lblCaption" Width="20" VerticalAlignment="Center">aaa</Label>
<local:PASCustomComboBox Height="23" x:Name="cmbComboBoxControl" VerticalAlignment="Center" Width="50"
IsEditable="True" Style="{StaticResource comboBoxStyle}">
</local:PASCustomComboBox>
<Button Height="23" Name="btnSearch" Width="25" Click="btnSearch_Click" Visibility="Collapsed"
VerticalAlignment="Center">...</Button>
<Label Height="23" Name="lblDescription" VerticalAlignment="Center" Width="20" Foreground="Blue">
</Label>
</Canvas>
</UserControl>
Here PASCustomComboBox is a class which inherites from combo box.
public class PASCustomComboBox : ComboBox
{
protected override void OnPreviewKeyDown(KeyEventArgs e)
{
if (e.Key == Key.Down || e.Key == Key.Up)
{
e.Handled = true;
return;
}
base.OnPreviewKeyDown(e);
}
}
The problem is that you are redefining the ControlTemplate without any visual tree in it:
<Style x:Key="comboBoxStyle" TargetType="{x:Type local:PASCustomComboBox}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:PASCustomComboBox}">
<ControlTemplate.Triggers>
<Trigger Property="local:PASCustomComboBox.IsEnabled" Value="false">
<Setter Property="Background" Value="Red"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
You'll want the triggers on the style instead of the controltemplate:
<Style x:Key="comboBoxStyle" TargetType="{x:Type local:PASCustomComboBox}">
<Style.Triggers>
<Trigger Property="local:PASCustomComboBox.IsEnabled" Value="false">
<Setter Property="Background" Value="Red"/>
</Trigger>
</Style.Triggers>
</Style>
You dont specify any visual elements in the control template of your style, just a trigger. It will render the empty template iirc.
Better edit the Trigger collection of the ComboBox in your style to add that trigger and you will keep the default ControlTemplate.
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