Сейчас ищут
Populate Selected Datagridview Row In Textboxes. Смотреть видео: C DataGridView Set Selected Row Items To TextBoxes, C Tutorial 21 Display Selected Row From Datagridview To TextBox In C, Display Selected Row From Datagridview To Textbox In C, C Get Selected Row Values From DataGridView Into TextBox In C With Source Code.