Thank you for writing.
If understand correctly you would like to perform a validation of the cell. This scenario is handled by the CellValidating
event and detailed information is available in our documentation: Data Validation
On a side note, I have deleted your other thread as it duplicates this one.
I hope this helps. Should you have further questions please do not hesitate to write back.
Telerik by Progress
Check out the Windows Forms project converter, which aids the conversion process from standard Windows Forms applications written in C# or VB to Telerik UI for WinForms. For more information check out this blog post
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