Telerik WPF GridView header text disappears when content is bound to tooltip

Question

I am following Telerik guide for displaying a tooltip on WPF GridView column headers. The task is to create a tooltip which would have same text as column header.

In generic.xml there is this style:

<Style TargetType="telerik:GridViewHeaderCell">
     <Setter Property="ToolTip" Value="{Binding RelativeSource={RelativeSource Self}, Path=Content}" />
</Style>

This does work and shows a tooltip when mouse is hovered over column header, however the actual header is being cleared.

I wonder why this is happening and how to fix it? GridViewHeaderCell inherits from ContentControl.

Answer 1

I ended up adding a converter because "Content" value appeared to be a TextBlock:

public class TooltipObject : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value != null)
            {
                return ((TextBlock)value).Text;
            }

            return value;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return value;
        }
    }

and the style looks like:

<utils:TooltipObject x:Key="tooltip" />

...

<Style TargetType="telerik:GridViewHeaderCell">
            <Setter Property="ToolTip" Value="{Binding RelativeSource={RelativeSource Self}, Path=Content, Mode=TwoWay, Converter={StaticResource tooltip}}" />
        </Style>