CODEWITHSUNDEEP
.netwpfxamlbindingstyles
PeterE
PeterE

Reputation: 5855

Style DataTrigger with reference to Type of parent control

On my Window there are several GroupBox Controls, each containing a Grid Control. To those Grids I want to asign a Style. But only to those Grids that are directly in a GroupBox, all other Grids should not be affected.

I have tried the following, which does not work as GetType() is no property.

<Style TargetType="Grid">
    <Style.Triggers>
        <DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=Self}, Path=Parent.GetType()}" Value="{x:Type GroupBox}">
           <!-- <Setter Property="..." Value="..."/> -->
        </DataTrigger>
    </Style.Triggers>
</Style>

I have found a workaround, but it's not really a beautiful solution, as I have to modify the GroupBoxes:

<Style TargetType="GroupBox">
    <Setter Property="Tag" Value="blub"/>
 </Style>
<Style TargetType="Grid">
    <Style.Triggers>
        <DataTrigger Binding="{Binding Path=Parent.Tag, RelativeSource={RelativeSource Mode=Self}}" Value="blub">
           <!-- <Setter Property="..." Value="..."/> -->
        </DataTrigger>
    </Style.Triggers>
</Style>

Obviously I could set the style for each Grid manually, but I'm trying to avoid that, as there are quite a lot of them. I hope you can find a way to make the first example work.

Upvotes: 9

Views: 11034

Answers (3)

bigbyte
bigbyte

Reputation: 119

This worked for me:

        <Style.Triggers>
            <DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type StatusBar}}, Path=DependencyObjectType.Name}" Value="StatusBar">
                <Setter Property="Margin" Value="0"/>
                <Setter Property="Padding" Value="0"/>
                <Setter Property="Background" Value="Chartreuse"/>
            </DataTrigger>
        </Style.Triggers>

It allows you to set style based on parent type without having to resort to Tag which should really be used by code rather than by markup.

Upvotes: 5

Amol Bavannavar
Amol Bavannavar

Reputation: 2062

Use following Code :

using DevExpress.Xpf.Core.Native;
using System;
using System.Globalization;
using System.Windows;
using System.Windows.Data;

namespace BindingErrorHelper
{
    public class IsTypeFoundConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            FrameworkElement element = value as FrameworkElement;
            Type type = parameter as Type;
            if (element != null && type != null)
            {
                element = LayoutHelper.FindElement(element,type);
                if (element != null)
                    return true;
            }
            return false;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return value;
        }
    }

    public class LayoutHelper
    {
        public static FrameworkElement FindElement(FrameworkElement treeRoot, Type type)
        {
        FrameworkElement parentElement = VisualTreeHelper.GetParent(treeRoot) as FrameworkElement;
        while (parentElement != null)
        {
            if (parentElement.GetType() == type)
                return parentElement;
            else
                parentElement = VisualTreeHelper.GetParent(parentElement) as FrameworkElement;
        }
        return null;
        }
    }
}

Write the XAML Code as :

<tt:IsTypeFoundConverter x:Key="isTypeFoundConverter"/>

<Style TargetType="Grid">
    <Style.Triggers>
        <DataTrigger Binding={Binding RelativeSource={RelativeSource Self}, Converter={StaticResource isTypeFoundConverter}, ConverterParameter={x:Type GroupBox}}" Value="true">
           <!-- <Setter Property="..." Value="..."/> -->
        </DataTrigger>
    </Style.Triggers>
</Style>

Upvotes: 1

Sarfaraz Nawaz
Sarfaraz Nawaz

Reputation: 361252

<DataTrigger Binding="{Binding Path=Parent.Tag, RelativeSource={RelativeSource Mode=Self}}" Value="blub">

This code would not work, because type of Mode is actually BindingMode which is an Enumeration, and none of it's member is Self. So this assignment Mode=Self is wrong in your code. To know the possible values of Mode, click this.

The correct way to write this is,

<DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GroupBox}}, Path=Tag}" Value="blub">

And of course, for this to work, you've to keep that Style for GroupBox which you've already written.

Upvotes: 9

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