Multilevel column header for DataGrid in WPF

Question

I have a DataGrid which needs to look like this:

As you c

Answer 1

    <DataGrid>
                                <DataGrid.Columns>
                                    <DataGridTemplateColumn Width="400">
                                        <DataGridTemplateColumn.Header>
                                            <StackPanel Width="400" HorizontalAlignment="Center">
                                                <Label HorizontalContentAlignment="Center" FontWeight="Bold">EXPERIMENT 1</Label>
                                                <Line Stroke="Black"
                                                      X1="0"
                                                      X2="400"
                                                      Y1="0"
                                                      Y2="0" />
                                                <StackPanel Width="400" Orientation="Horizontal">
                                                    <Label Width="200" HorizontalContentAlignment="Center">MODE 1</Label>
                                                    <Line Stroke="Black"
                                                          X1="1"
                                                          X2="1"
                                                          Y1="0"
                                                          Y2="26" />
                                                    <Label Width="200" HorizontalContentAlignment="Center">MODE 2</Label>
                                                </StackPanel>
                                                <Line Stroke="Black"
                                                      X1="0"
                                                      X2="400"
                                                      Y1="0"
                                                      Y2="0" />
                                                <StackPanel Width="400" Orientation="Horizontal">
                                                    <Label Width="100" HorizontalContentAlignment="Center">VALUE 1</Label>
                                                    <Line Stroke="Black"
                                                          X1="1"
                                                          X2="1"
                                                          Y1="0"
                                                          Y2="26" />
                                                    <Label Width="100" HorizontalContentAlignment="Center">VALUE 2</Label>
                                                    <Line Stroke="Black"
                                                          X1="1"
                                                          X2="1"
                                                          Y1="0"
                                                          Y2="26" />
                                                    <Label Width="100" HorizontalContentAlignment="Center">VALUE 1</Label>
                                                    <Line Stroke="Black"
                                                          X1="1"
                                                          X2="1"
                                                          Y1="0"
                                                          Y2="26" />
                                                    <Label Width="100" HorizontalContentAlignment="Center">VALUE 2</Label>
                                                </StackPanel>
                                            </StackPanel>
                                        </DataGridTemplateColumn.Header>
                                        <DataGridTemplateColumn.CellTemplate>
                                            <DataTemplate>
                                                <StackPanel Width="400" Orientation="Horizontal">
                                                    <ComboBox Width="100" />
                                                    <ComboBox Width="100" />
                                                    <ComboBox Width="100" />
                                                    <ComboBox Width="100" />
                                                </StackPanel>
                                            </DataTemplate>
                                        </DataGridTemplateColumn.CellTemplate>
                                    </DataGridTemplateColumn>
                                    <DataGridTemplateColumn Width="400">
                                        <DataGridTemplateColumn.Header>
                                            <StackPanel Width="400" HorizontalAlignment="Center">
                                                <Label HorizontalContentAlignment="Center" FontWeight="Bold">EXPERIMENT 2</Label>
                                                <Line Stroke="Black"
                                                      X1="0"
                                                      X2="400"
                                                      Y1="0"
                                                      Y2="0" />
                                                <StackPanel Width="400" Orientation="Horizontal">
                                                    <Label Width="200" HorizontalContentAlignment="Center">MODE 1</Label>
                                                    <Line Stroke="Black"
                                                          X1="1"
                                                          X2="1"
                                                          Y1="0"
                                                          Y2="26" />
                                                    <Label Width="200" HorizontalContentAlignment="Center">MODE 2</Label>
                                                </StackPanel>
                                                <Line Stroke="Black"
                                                      X1="0"
                                                      X2="400"
                                                      Y1="0"
                                                      Y2="0" />
                                                <StackPanel Width="400" Orientation="Horizontal">
                                                    <Label Width="100" HorizontalContentAlignment="Center">VALUE 1</Label>
                                                    <Line Stroke="Black"
                                                          X1="1"
                                                          X2="1"
                                                          Y1="0"
                                                          Y2="26" />
                                                    <Label Width="100" HorizontalContentAlignment="Center">VALUE 2</Label>
                                                    <Line Stroke="Black"
                                                          X1="1"
                                                          X2="1"
                                                          Y1="0"
                                                          Y2="26" />
                                                    <Label Width="100" HorizontalContentAlignment="Center">VALUE 1</Label>
                                                    <Line Stroke="Black"
                                                          X1="1"
                                                          X2="1"
                                                          Y1="0"
                                                          Y2="26" />
                                                    <Label Width="100" HorizontalContentAlignment="Center">VALUE 2</Label>
                                                </StackPanel>
                                            </StackPanel>
                                        </DataGridTemplateColumn.Header>
                                        <DataGridTemplateColumn.CellTemplate>
                                            <DataTemplate>
                                                <StackPanel Width="400" Orientation="Horizontal">
                                                    <ComboBox Width="100" />
                                                    <ComboBox Width="100" />
                                                    <ComboBox Width="100" />
                                                    <ComboBox Width="100" />
                                                </StackPanel>
                                            </DataTemplate>
                                        </DataGridTemplateColumn.CellTemplate>
                                    </DataGridTemplateColumn>
                                </DataGrid.Columns>
                            </DataGrid>

Answer 2

As far as I know, the standard DataGrid does not support it, so you need to look for alternatives. I can offer the use of a Grid capabilities, such as: Grid.RowDefinitions, Grid.ColumnDefinitions. To illustrate this feature, I created a sample, who need to complete:

<Window x:Class="MultiHeaderDataGrid.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525"
    WindowStartupLocation="CenterScreen">

<Window.Resources>
    <Style TargetType="{x:Type Border}">
        <Setter Property="Background" Value="Bisque" />
        <Setter Property="TextBlock.FontSize" Value="14" />
        <Setter Property="BorderBrush" Value="Black" />
        <Setter Property="BorderThickness" Value="1" />
        <Setter Property="HorizontalAlignment" Value="Stretch" />
    </Style>
</Window.Resources>

<Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="auto"/>
        <RowDefinition Height="auto"/>
        <RowDefinition Height="auto"/>
        <RowDefinition Height="2*"/>
    </Grid.RowDefinitions>

    <Grid Grid.Row="0">                 
        <Border Grid.Column="1" Grid.ColumnSpan="4">
            <TextBlock Text="Main application" TextAlignment="Center" />
        </Border>
    </Grid>

    <Grid Grid.Row="1">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>

        <Border Grid.Column="0">                
            <TextBlock Grid.Column="1" Text="Experiment 1" TextAlignment="Center" />             
        </Border>

        <Border Grid.Column="1">
            <TextBlock Grid.Column="1" Text="Experiment 2" TextAlignment="Center" />
        </Border>
    </Grid>

    <Grid Grid.Row="2">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>

        <Border Grid.Column="0">
            <TextBlock Grid.Column="1" Text="Mode 1" TextAlignment="Center" />
        </Border>

        <Border Grid.Column="1">
            <TextBlock Grid.Column="1" Text="Mode 2" TextAlignment="Center" />
        </Border>

        <Border Grid.Column="2">
            <TextBlock Grid.Column="1" Text="Mode 1" TextAlignment="Center" />
        </Border>

        <Border Grid.Column="4">
            <TextBlock Grid.Column="1" Text="Mode 2" TextAlignment="Center" />
        </Border>
    </Grid>

    <Grid Grid.Row="3">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>

        <Border Grid.Column="0">
            <TextBlock Grid.Column="1" Text="Mode 1" TextAlignment="Center" />
        </Border>

        <Border Grid.Column="1">
            <TextBlock Grid.Column="1" Text="Mode 2" TextAlignment="Center" />
        </Border>

        <Border Grid.Column="2">
            <TextBlock Grid.Column="1" Text="Mode 1" TextAlignment="Center" />
        </Border>

        <Border Grid.Column="4">
            <TextBlock Grid.Column="1" Text="Mode 2" TextAlignment="Center" />
        </Border>
    </Grid>

    <DataGrid Name="datagrid1" AutoGenerateColumns="False" Grid.Row="3" RowHeaderWidth="10" Loaded="datagrid1_Loaded">
        <DataGrid.Columns>
            <DataGridTextColumn x:Name="Column1" Binding="{Binding Name}" Header="column 1" Width="100" />
            <DataGridTextColumn x:Name="Column2" Binding="{Binding Age}"  Header="column 2" Width="80" />
            <DataGridTextColumn x:Name="Column3" Binding="{Binding Sample}" Header="column 3" Width="80" />
            <DataGridTextColumn x:Name="Column4" Binding="{Binding Sample}" Header="column 4" Width="*" />
        </DataGrid.Columns>
    </DataGrid>
</Grid>
</Window>

Output

If you want, you can set the ColumnDefinition Width of a Grid, like a DataGrid column:

<Grid.ColumnDefinitions>
    <ColumnDefinition Width="{Binding ElementName=SampleDataGrid, Path=RowHeaderWidth}" />
    <ColumnDefinition Width="{Binding ElementName=Column1, Path=ActualWidth}" />
    <ColumnDefinition Width="{Binding ElementName=Column2, Path=ActualWidth}" />
</Grid.ColumnDefinitions>   

Also, you need to define the same Style for the Grid header and DataGrid.