C# 如何以wpf样式绑定按钮命令

我使用radgridview标题中带有按钮的样式作为HeaderCellStyle。按钮放置正确，但命令未调用

下面是我的代码：

<telerik:GridViewImageColumn Header="" 
                                         Width="30"
                                         ImageHeight="30" 
                                         IsResizable="False" 
                                         DataMemberBinding="{Binding Image}"                                             
                                         HeaderCellStyle="{StaticResource ButtonStyle}"  >
              </telerik:GridViewImageColumn>

可用于绑定到单元格的datacontext：

<telerik:RadButton x:Name="ClearButton"  Content="{Binding ClearButton,Source={StaticResource FrameworkInfrastructureResources}}"
                       ToolTip="{Binding ClearTooltip,Source={StaticResource FrameworkInfrastructureResources}}"  Margin="5"
                       IsEnabled="True" 
                       HorizontalContentAlignment="Center" 
                       Command="{Binding Path=DataContext.ClearMessagesCommand,,RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type telerik:GridViewHeaderCell}}}"
</telerik:RadButton>

  public ICommand ClearMessagesCommand { get; set; }
  ClearMessagesCommand = new DelegateCommand(() => { this.Messages.Clear(); });

<telerik:RadButton x:Name="ClearButton"  Content="{Binding ClearButton,Source={StaticResource FrameworkInfrastructureResources}}"
                       ToolTip="{Binding ClearTooltip,Source={StaticResource FrameworkInfrastructureResources}}"  Margin="5"
                       IsEnabled="True" 
                       HorizontalContentAlignment="Center" 
                       Command="{Binding Path=DataContext.ClearMessagesCommand,,RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type telerik:GridViewHeaderCell}}}"
</telerik:RadButton>