Question

I’m working on following code .. of course, the solution gets built and compiles all that but when I hit F5 or start I get following error message.

Cannot convert the value in attribute ‘Style’ to object of type ‘System.Windows.Style’. Can only base on a Style with target type that is base type ‘Rectangle’. Error at object ‘System.Windows.Shapes.Rectangle’ in markup file

This is the code:

   <Style x:Key="Connector1" TargetType="Rectangle" BasedOn="{StaticResource Style123}">
    <Setter Property="Fill" Value="Aqua"  />
</Style>
<Style x:Key="Connector1_DragThumb" TargetType="Rectangle" BasedOn="{StaticResource Style123}">
    <Setter Property="IsHitTestVisible" Value="true"/>
    <Setter Property="Fill" Value="Yellow"/>
    <Setter Property="Stroke" Value="Black"/>
</Style>

Any help is appreciated.

Regards.

Answer 1

The error suggests that StaticResource Style123 on which you are basing this style does not itself have TargetType="Rectangle".

You can only base a Rectangle style on another Rectangle style or a base class thereof (or the default by using {StaticResource {x:Type Rectangle}}).