Change content in datagridcell on datatrigger

Question

I want to change the content of a DataGridCell. I have a column in the datagridview like so

<DataGridCheckBoxColumn CellStyle="ChangeContentOfCellSstyle"...

Then I have a DataTrigger like so:

<Style TargetType="DataGridCell" x:Key="ChangeContentOfCellSstyle">
    <Style.Triggers>
        <DataTrigger Binding="{Binding IsWashed}" Value="True">
            <Setter Property="Content" Value="The new value for the cell."/> 
            <Setter Property="Background" Value="Red"/> //sets the background of the cell to red just to show the trigger is working
        </DataTrigger>
    </Style.Triggers>
</Style>

But the content of the cell is not changing. Not even when I try the same with a DataGridTextColumn although the cell turns red.

Answer 1

I've removed my previous answer since using a template selector is a much better way of doing this.

first I create a DataTemplateSelector class that can be used to switch between DataTemplates based on a binding, note the 2 properties that take in references to the styles that will be applied, I could have used find resource here but I think this is cleaner and doesn't require view designers to stick to hard coded template keys.

public class IsWashedStyleSelector : DataTemplateSelector
{

    public DataTemplate TrueStyle { get; set; }
    public DataTemplate FalseStyle { get; set; }

    public override DataTemplate SelectTemplate(object item, DependencyObject container)
    {
        TestClass targetItem = item as TestClass;
        if (targetItem != null)
        {
            return targetItem.IsWashed ? TrueStyle : FalseStyle;
        }
        return base.SelectTemplate(item, container);
    }
}

Now to use this template selector I have to define 2 data templates and also instance the selector in xaml resources.

<DataTemplate x:Key="styleIsWashedTrue">
    <Button>It's true</Button>
</DataTemplate>
<DataTemplate x:Key="styleIsWashedFalse">
    <Label>is false</Label>
</DataTemplate>

<local:IsWashedStyleSelector x:Key="isWashedStyleSelector"  TrueStyle="{StaticResource styleIsWashedTrue}" FalseStyle="{StaticResource styleIsWashedFalse}"/>

Finally the selector can be used in a DataGridTemplateColumn like so.

<DataGrid ItemsSource="{Binding Items}" AutoGenerateColumns="False">
        <DataGrid.Columns>
            <DataGridCheckBoxColumn Binding="{Binding IsWashed}"/>
            <DataGridTextColumn Binding="{Binding Text}"/>
            <DataGridTemplateColumn CellTemplateSelector="{StaticResource isWashedStyleSelector}"/>
        </DataGrid.Columns>
    </DataGrid>