How Can I Show Messagebox From Code Behind In Aspx Page (C#) Based On If And Else Condition On Combobox Selected Index Changed Event .

helloo Awadhendra . my question is how i can show messege box from code behind file (.cs file) without creating java script function on designing file (aspx page) . i have used some if and else condition into my c# code where i have checked the selected item of dropdown list and according to selection i have put some if and else conditions and inside the if and else conditions i want to put code which can show messege box when that block of (if or else ) code execute ....

means i want to show message box from cs file and that show message box code must be inside the if and else condition .