Command in DataTemplate is not called

Question

First off all, my View and ViewModel are connected correctly. But I can't get through binding in DataTemplate.

So, I have DataTemplate in Windows.Resources:

<Window.Resources>
    <DataTemplate x:Key="DataGridHeader">
            <DockPanel>
                <TextBlock DockPanel.Dock="Top" TextAlignment="Left" Text="{Binding Content, RelativeSource={RelativeSource Mode=TemplatedParent}}" Margin="5"/>
                <TextBox DockPanel.Dock="Top" BorderBrush="#3d3d3d" BorderThickness="1" Margin="5" Height="22">
                </TextBox>
                <Button DockPanel.Dock="Top" Height="30" Command="{Binding DataContext.OnFilterCommand, RelativeSource={RelativeSource AncestorType=Window}}"></Button>
            </DockPanel>
    </DataTemplate>
</Window.Resources>

and then, I have my DataGrid:

    <DataGrid x:Name="DataGridItems"
              Grid.Row="1"
              EnableRowVirtualization="True"
              ItemsSource="{Binding Items, Mode=TwoWay}" 
              RowHeight="25"
              RowHeaderWidth="0"
              VerticalContentAlignment="Center"
              HorizontalGridLinesBrush="#dddddd"
              VerticalGridLinesBrush="#dddddd"
              AlternatingRowBackground="#f2f2f2"
              AutoGenerateColumns="False"
              Background="#cecece"
              CanUserAddRows="False">
        <DataGrid.CellStyle>
            <Style TargetType="{x:Type DataGridCell}">
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type DataGridCell}">
                            <Grid Background="{TemplateBinding Background}">
                                <ContentPresenter VerticalAlignment="Center" />
                            </Grid>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
        </DataGrid.CellStyle>         
        <DataGrid.ColumnHeaderStyle>
            <Style TargetType="{x:Type DataGridColumnHeader}">
                <Setter Property="Padding" Value="0" />
                <Setter Property="FontWeight" Value="Bold"/>
                <Setter Property="Foreground" Value="#111111"></Setter>
                <Setter Property="Background" Value="#cecece" />
                <Setter Property="BorderBrush" Value="#111111" />
                <Setter Property="BorderThickness" Value="0" />
                <Setter Property="HorizontalContentAlignment" Value="Stretch" />
                <Setter Property="SeparatorVisibility" Value="Visible"></Setter>
            </Style>
        </DataGrid.ColumnHeaderStyle>            
        <DataGrid.Columns>
            <DataGridTextColumn Header="Id" Binding="{Binding Path=Id}" HeaderTemplate="{StaticResource DataGridHeader}" Width="65"  />
            <DataGridTextColumn Header="Name" Binding="{Binding Path=Name}" HeaderTemplate="{StaticResource DataGridHeader}" Width="150" />
        </DataGrid.Columns>
    </DataGrid>

in my ViewModel I have:

private ICommand _onLoadedCommand;
public ICommand OnFilterCommand => _onLoadedCommand ?? (_onLoadedCommand = new DelegateCommand(OnFilter));

    private void OnFilter()
    {
        Debug.WriteLine("Works!");
    }

and it doesn't work! I looked every where. I looked at this article: http://nosalan.blogspot.com/2013/10/wpf-datagrid-with-filtering-mvvm.html

and it looks to me that I'm doing everything correct.

What am I missing?

Answer 1

You are missing nothing. I have tested your code and it works! The command will be executed. The only difference - i have used not a DelegateCommand, but my implementation, so i don't think, that it is a reason. Restart VS, reboot computer. It should work!