how to get cell value of gridview in asp.net C# in text box

Question

I have one gridview in that there are 4 columns namely "User ID","Description","Display Password","Change Password". I have put an Image Button in Change Password Column for each cell. Below the Gridview there are 3 text boxes. When I click on Change Password, the User ID of that particular row should be displayed in text box 1. How to do this in asp.net with C# and back end is MySql DB server.