How to Show DataGridView Combobox Selected Value in DataGridView Textbox

hi, i don't know c# very well, i need a little help. i have a DataGridView with Two Columns 1st Column is combobox and 2nd Column is Textbox. i just want that when i select DataGridView Combobox value then that value show in DataGridView TextBox. ComboboxColumn Name is "dgv_cb" and TextBoxColumn Name is "dgv_txt". Please help me how can i do that.

Thanks