How to switch the Style of a Border depending on a bool in wpf (mvvm)

Question

So This is (a part of) my border in the xaml

    <DataTemplate DataType="{x:Type viewModel:FunctionProviderViewModel}">
    <Border Margin="4"
            Background="PapayaWhip"
            CornerRadius="4"                
            IsEnabled="{Binding IsSimpleModeActive}"
            Style="{StaticResource ResourceKey=AcpBorder}">

Im populating a Control with this DataTemplate. I added another Border with x:Key="SimpleAcpBorder" and i added a bool to my viewmodel (which will is bound to a checkbox). Now i want to set the style to simple if the checkbox is checked and to regular else. Does anybody know how to achieve this?

thanks in advance!

EDIT:

my datatemplate looks like this now

    <DataTemplate DataType="{x:Type viewModel:FunctionProviderViewModel}">
    <Border Background="PapayaWhip">
        <Border.Style>
            <Style TargetType="Border"                       
                   BasedOn="{StaticResource ResourceKey=AcpBorder}">
                <Style.Triggers>
                    <DataTrigger Binding="{Binding IsSimpleModeActive}"
                                 Value="True">
                        <Setter Property="Margin"
                                Value="0" />
                        <Setter Property="CornerRadius"
                                Value="0" />                            
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </Border.Style>

        <Border.Effect>
            <DropShadowEffect BlurRadius="10" ShadowDepth="5" />
        </Border.Effect>
        <TreeViewItem VerticalContentAlignment="Center"
                      Background="Transparent"

and in another xaml my AcpBoarder stays untouched:

    <Style x:Key="AcpBorder"
       TargetType="Border">
    <Setter Property="VerticalAlignment"
            Value="Stretch" />
    <Setter Property="CornerRadius"
            Value="3" />
    <Setter Property="Padding"
            Value="4" />
    <Setter Property="Margin"
            Value="2" />
</Style>

But somehow the Trigger doesnt seem to work for me. Any ideas?

Thank you very much

EDIT2:

    System.Windows.Data Warning: 56 : Created BindingExpression (hash=54724182) for    Binding (hash=28450086)
    System.Windows.Data Warning: 58 :   Path: 'IsSimpleModeActive'
    System.Windows.Data Warning: 60 : BindingExpression (hash=54724182): Default mode resolved to OneWay
    System.Windows.Data Warning: 61 : BindingExpression (hash=54724182): Default update trigger resolved to PropertyChanged
    System.Windows.Data Warning: 62 : BindingExpression (hash=54724182): Attach to         System.Windows.Controls.Border.NoTarget (hash=22755592)
    System.Windows.Data Warning: 67 : BindingExpression (hash=54724182): Resolving source 
    System.Windows.Data Warning: 70 : BindingExpression (hash=54724182): Found data context element: Border (hash=22755592) (OK)
    System.Windows.Data Warning: 78 : BindingExpression (hash=54724182): Activate with root item FunctionProviderViewModel (hash=3473742)
    System.Windows.Data Warning: 107 : BindingExpression (hash=54724182):   At level 0 using cached accessor for FunctionProviderViewModel.IsSimpleModeActive: RuntimePropertyInfo(IsSimpleModeActive)
    System.Windows.Data Warning: 104 : BindingExpression (hash=54724182): Replace item at level 0 with FunctionProviderViewModel (hash=3473742), using accessor RuntimePropertyInfo(IsSimpleModeActive)
    System.Windows.Data Warning: 101 : BindingExpression (hash=54724182): GetValue at level 0 from FunctionProviderViewModel (hash=3473742) using RuntimePropertyInfo(IsSimpleModeActive): 'False'
    System.Windows.Data Warning: 80 : BindingExpression (hash=54724182): TransferValue - got raw value 'False'
    System.Windows.Data Warning: 89 : BindingExpression (hash=54724182): TransferValue - using final value 'False'
The thread '' (0x454) has exited with code 0 (0x0).

Instead of trying to do this using two separate styles, why not have just one (say "AcpBorder") which includes a data trigger (bound to your bool property) that changes the necessary properties, resulting in the "simple" border appearance? — Andrew Stephens

Martin Liversage Martin Liversage · Accepted Answer · 2014-08-06T11:35:51

You can use a DataTrigger for this. However, you cannot apply a DataTrigger directly to your border. Instead you have to apply it to a Style.

From the comments it seems that you use the style AcpBorder in many places and you do not want to create a coupling between this style and a view-model property named IsSimpleModeActive. One way to do that is to set the Border.Style property directly and let the style be based on the AcpBorder style:

<Border Margin="4" Background="PapayaWhip" CornerRadius="4" IsEnabled="False">
  <Border.Style>
    <Style TargetType="Border" BasedOn="{StaticResource AcpBorder}">
      <Style.Triggers>
        <DataTrigger Binding="{Binding IsSimpleModeActive}" Value="True">
          <Setter Property="IsEnabled" Value="True"/>

          ... more setters

        </DataTrigger>
      </Style.Triggers>
    </Style>
  </Border.Style>
</Border>

How to switch the Style of a Border depending on a bool in wpf (mvvm)

1 Answers