Thank you for writing.
The assembly that needs to be referenced is Telrik.WinControls.UI.dll
, and the namespace of RadMessageBox
. Please refer to this help article
, which demonstrates how to make use of this compoenent.
I hope the provided information addresses your question. Should you have any other questions, do not hesitate to contact us.
All the best,
the Telerik team
Q1’11 SP1 of RadControls for WinForms is available for download
; also available is the Q2'11 Roadmap
for Telerik Windows Forms controls.