Could not load file or assembly 'System.ComponentModel.Composition, Version=2009.7.8.0, Culture=neutral, PublicKeyToken=13e5ffd4e05db186' or one of its dependencies

[David]

I am trying to use the RadRichTextBox control. I know this error has a posting in the forums but I need to know what is the minimum version of the telerik.windows.control, telerik.windows.data, and telerik.windows.documents for .net 4.0--as we are using the .net 4 version of system.componentmodel.composition for our project.

I am using control version 2011.2.920.35, data version 2011.2.920.35, documents version 2011.2.920.35 and the componentmodel is 4.0.0.0. I got this info from properties for each file in my project.

[Iva Toteva]

Hello David,

As noted in this article RadControls for WPF ship different assemblies built for .NET 3.5 and 4.0.The last two digits in the version of the controls (35 in your case) mean that you are using the 3.5 version of the controls.

RadRichTextBox uses MEF to provide different extensibility options and needs System.ComponentModel.Composition in order to run. However, .NET 3.5 does not include MEF, so we have prepared an assembly from the source which is of the version you quoted and distribute it with the 3.5 version of the controls to be used in projects targeting WPF 3.5.

In short, if your project is targeting .NET 4, you should use the version of the controls that has been built for WPF 4.0 and the built-in Composition assembly. You can download a hotfix or an installer for the 4.0 version of the controls (2011.2.920.40) from your account.

Best wishes,
Iva Toteva
the Telerik team