how to show custom context menu strip on gridview cell

context menu having items "red, green,purple,gray" colors

and when any color is clicked ...then background color of that particular cell should changed to selected color

Hello Abhi,

Thank you for writing.

The default RadGridView context menu can be customized in the ContextMenuOpening event handler. Please refer to the Modifying the Default Context Menu help article. As to the question about customizing the cell style, the appropriate solution is to use the CellFormatting event. Our GridView >> Formatting Cells help article demonstrates a sample approach. You just need to keep to which row and column belongs the cell and apply the desired look.

I hope this information helps. Should you have further questions, I would be glad to help.
Regards,
Dess
Telerik