How to Update a row in Datagrid

Hi Everyone,

I am working on DataGrid in C#. Actually I have relationship between two table(Customers and orders) and
displaying on DataGrid. I want to update a record of orders table when I click or select on one datagrid row,
all the records of one row (order table) goes to Textbox control one by one then I or user can update the table easily.

How to create a click-event on Datagrid one Row.

Thanks