C# Datagridview to textbox

Question

Hi, need help on getting the values from datagridview to textboxes, i am having a datagridview getting data's from SQL which has 4 column and number of rows retrieved from sql, i am having 4 textboxes, i want the datagridview selected row's column values to the textboxes, tried few things which i am getting error.
 
Kindly advice