I have experience with Linq Expressions and like to implement my own.
The gridState.FilterDescriptors.Add method accepts anything of interface IFilterDescriptor.
However, when I give it my own implementation of IFilterDescriptor, it compiles fine but then throws an error during runtime:
System.InvalidCastException: 'Unable to cast object of type 'MyFilterDescriptor' to type 'Telerik.DataSource.FilterDescriptor'.'
I thought to inherit Telerik.DataSource.FilterDescriptor and Telerik.DataSource.CompositeFilterDescriptor and override the CreateFilterExpression method, but that didn't work either, as it always ends up calling the method in the base FilterDescriptor.
Is this by design, or is there a way now or in the future to implement my own IFilterDescriptor?