How to Center Align row numbers in Datagrid row header in WPF

Question

I use this code for row numbers in Datagrid.

<DataGrid Name="DataGrid" LoadingRow="DataGrid_LoadingRow" ...

void DataGrid_LoadingRow(object sender, DataGridRowEventArgs e)
{
   e.Row.Header = (e.Row.GetIndex()).ToString(); 
}

How to center align these numbers in row header?

Answer 1

<DataGrid x:Name="dataGrid" AutoGenerateColumns="False" LoadingRow="OnLoadingRow">
    <DataGrid.Columns>
        <DataGridTextColumn Header="Id" Binding="{Binding Id}"/>
        <DataGridTextColumn Header="Name" Binding="{Binding Name}"/>
    </DataGrid.Columns>
    <DataGrid.RowHeaderTemplate>
        <DataTemplate>
            <Label HorizontalAlignment="Center"
                   Content="{Binding RelativeSource={RelativeSource AncestorType=DataGridRow},
                                     Path=Header}"/>
        </DataTemplate>
    </DataGrid.RowHeaderTemplate>
</DataGrid>

Answer 2

To center align the row numbers in a DataGrid RowHeader, use a custom RowHeaderStyle Template.

You can generate the default template in Visual Studio 2012 or later by right-click on the DataGrid in design mode and select “Edit Additional Templates” -> “Edit RowHeaderStyle” -> “Edit a Copy”. Once you have given the new style resource a name and chosen where to generate it, you can then modify the generated XAML template according to your requirements.

Since each revision of Windows will generate a slightly different template, but on Windows 8 and above, all you have to do is set the DataGridHeaderBorder StackPanel in Themes:DataGridHeaderBorder to

HorizontalAlignment="Center"

I'll include a snippet of the Windows 10 Fall Update DataGrid RowHeaderStyle Template.

<DataGrid.Resources>
            <BooleanToVisibilityConverter x:Key="bool2VisibilityConverter"/>
            <Style x:Key="RowHeaderGripperStyle" TargetType="{x:Type Thumb}">
                <Setter Property="Height" Value="8"/>
                <Setter Property="Background" Value="Transparent"/>
                <Setter Property="Cursor" Value="SizeNS"/>
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type Thumb}">
                            <Border Background="{TemplateBinding Background}" Padding="{TemplateBinding Padding}"/>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
            <Style x:Key="DataGridRowHeaderStyle1" TargetType="{x:Type DataGridRowHeader}">
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type DataGridRowHeader}">
                            <Grid>
                                <Themes:DataGridHeaderBorder BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" IsPressed="{TemplateBinding IsPressed}" IsHovered="{TemplateBinding IsMouseOver}" IsSelected="{TemplateBinding IsRowSelected}" Orientation="Horizontal" Padding="{TemplateBinding Padding}" SeparatorBrush="{TemplateBinding SeparatorBrush}" SeparatorVisibility="{TemplateBinding SeparatorVisibility}">
                                <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
                                        <ContentPresenter RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="Center"/>
                                        <Control SnapsToDevicePixels="false" Template="{Binding ValidationErrorTemplate, RelativeSource={RelativeSource AncestorType={x:Type DataGridRow}}}" Visibility="{Binding (Validation.HasError), Converter={StaticResource bool2VisibilityConverter}, RelativeSource={RelativeSource AncestorType={x:Type DataGridRow}}}"/>
                                    </StackPanel>
                                </Themes:DataGridHeaderBorder>
                                <Thumb x:Name="PART_TopHeaderGripper" Style="{StaticResource RowHeaderGripperStyle}" VerticalAlignment="Top"/>
                                <Thumb x:Name="PART_BottomHeaderGripper" Style="{StaticResource RowHeaderGripperStyle}" VerticalAlignment="Bottom"/>
                            </Grid>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
        </DataGrid.Resources>

Answer 3

Simply style for RowHeader like this

        <DataGrid>
            <DataGrid.RowHeaderStyle>
                <Style TargetType="DataGridRowHeader">
                    <Setter Property="HorizontalContentAlignment" Value="Center"></Setter>
                </Style>
            </DataGrid.RowHeaderStyle>
        </DataGrid>

Answer 4

I use it like Cuong Tran Duc answered, but with some padding you can improve the look:

<DataGrid.RowHeaderStyle><Style TargetType="DataGridRowHeader">
    <Setter Property="HorizontalContentAlignment" Value="Center"></Setter>
    <Setter Property="Padding" Value="5 0"></Setter></Style>
</DataGrid.RowHeaderStyle>