GroupRowStyleSelector

You can use RadGridView's GroupRowStyleSelector property if you need to style group rows differently based on a specific condition.

ear in mind that the GroupRowStyle takes precedence over the GroupRowStyleSelector and will overwrite it if both are defined simultaneously.

To achieve this, first create a new class that inherits from the StyleSelector class and override its SelectStyle method:

Example 1: The GroupRowStyleSelector class

C#

	public class GroupRowStyleSelector : StyleSelector
	{
	    public override Style SelectStyle(object item, DependencyObject container)
	    {
	        var group = item as QueryableCollectionViewGroup;
	        if (group.ItemCount > 1)
	        {
	            return BigGroupStyle;
	        }
	        else
	        {
	            return SmallGroupStyle;
	        }
	    }
	
	    public Style BigGroupStyle { get; set; }
	    public Style SmallGroupStyle { get; set; }
	}

VB.NET

	Public Class GroupRowStyleSelector
	    Inherits StyleSelector
	    Public Overrides Function SelectStyle(item As Object, container As DependencyObject) As Style
	        Dim group = TryCast(item, CollectionViewGroup)
	
	        If group IsNot Nothing Then
	            If group.ItemCount > 1 Then
	                Return BigGroupStyle
	            Else
	                Return SmallGroupStyle
	            End If
	        End If
	
	        Return Nothing
	    End Function
	
	    Public Property BigGroupStyle() As Style
	        Get
	            Return m_BigGroupStyle
	        End Get
	        Set
	            m_BigGroupStyle = Value
	        End Set
	    End Property
	    Private m_BigGroupStyle As Style
	
	    Public Property SmallGroupStyle() As Style
	        Get
	            Return m_SmallGroupStyle
	        End Get
	        Set
	            m_SmallGroupStyle = Value
	        End Set
	    End Property
	    Private m_SmallGroupStyle As Style
	End Class

In the XAML file, define the style selector as a resource and set the properties of the BigGroupStyle and SmallGroupStyle:

Example 2: Setting the BigGroupStyle and SmallGroupStyle

XAML

	<Window.Resources>
	    <my:GroupRowStyleSelector x:Key="GroupRowStyleSelector">
	        <my:GroupRowStyleSelector.BigGroupStyle>
	            <Style TargetType="telerik:GroupHeaderRow">
	                <Setter Property="Background" Value="Red" />
	            </Style>
	        </my:GroupRowStyleSelector.BigGroupStyle>
	        <my:GroupRowStyleSelector.SmallGroupStyle>
	            <Style TargetType="telerik:GroupHeaderRow">
	                <Setter Property="Background" Value="Yellow" />
	            </Style>
	        </my:GroupRowStyleSelector.SmallGroupStyle>
	    </my:GroupRowStyleSelector>
	</Window.Resources>

If you're using GroupRenderMode="Nested" the style should target the GridViewGroupRow element.

The "my:" prefix before GroupRowStyleSelector specifies the mapping for the namespace of the project: xmlns:my="..."

Finally, set the GroupRowStyleSelector property:

Example 3: Setting the GroupRowStyleSelector property

XAML

	<telerik:RadGridView GroupRowStyleSelector="{StaticResource GroupRowStyleSelector}" />

And here is the final result:

Figure 1: The group footer rows styled using the GroupRowStyleSelector property

See Also

• Styling Group Row

• CellStyleSelector