C# MVVM How to add Command to TextBlock

Question

I'm trying to add a command to my TextBlock but haven't had any success yet. I tried following:

In XAML I've got a ItemsControl where I'm adding my TextBlocks:

<ItemsControl ItemsSource="{Binding CellCollection}">
                <ItemsControl.ItemTemplate>
                    <DataTemplate>
                        <TextBlock Background="{Binding Path=CellBackgroundColor}">
                            <TextBlock.InputBindings>
                            <MouseBinding Command="{Binding TestCommand}" MouseAction="LeftClick"/>
                            </TextBlock.InputBindings>
                        </TextBlock>                       
                    </DataTemplate>
                </ItemsControl.ItemTemplate>
            <ItemsControl.ItemsPanel>
                <ItemsPanelTemplate>
                      <UniformGrid Grid.Row="0" Rows="25" Columns="25">
                </UniformGrid>
                </ItemsPanelTemplate>
            </ItemsControl.ItemsPanel>
            </ItemsControl>

As you see I tried to add the MouseBinding like you would do it usually but since I'm adding the Textblocks via my MainWindowViewModel it isn't working.

MainWindowViewModel Code:

public MainWindowViewModel()
{
    TestCommand = new RelayCommand(Test);
    CellCollection = new ObservableCollection<Cell>();

    for (int iRow = 1; iRow < 26; iRow++)
    {
        for (int iColumn = 1; iColumn < 26; iColumn++)
        {
            CellCollection.Add(new Cell() { Row = iRow, Column = iColumn, IsAlive = false, CellBackgroundColor = new SolidColorBrush(Colors.Red) });
        }
    }
}

void Test(object parameter)
{
    //...
}

I'm pretty new to MVVM and trying to learn the framework. What am I missing out? I guess since the ItemsSource is set to CellCollection it is looking for the TestCommand in there but can't find it? Or am I wrong?

Answer 1

Try to specify a RelativeSource for the binding:

<TextBlock Background="{Binding Path=CellBackgroundColor}">
    <TextBlock.InputBindings>
        <MouseBinding Command="{Binding DataContext.TestCommand, 
                    RelativeSource={RelativeSource AncestorType=ItemsControl}}" MouseAction="LeftClick"/>
    </TextBlock.InputBindings>
</TextBlock>

The DataContext of the TextBlock in the ItemTemplate is the corresponding Cell object and not the MainWindowViewModel and that's why you can't bind directly to the TestCommand property.