In order to get the value of the selected row, you can use the SelectedItem property of the RadGridView. You can find more information regarding it at the following documentation page - Basic Selection - Selected Items.
So in your case, the code that you can apply is something similar to the following example:
var name = ((Person)radGridView.SelectedItem).Name; //c#
Dim name = DirectCast(radGridView.SelectedItem, Person).Name //VB.Net
The example assumes that the objects bound to the RadGridView are of type Person, so you can make the necessary changes at your end.
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