error when addind a DataGridViewCheckBoxCell to data grid view

Hi all
I have a data grid view witch is populated with DataGridViewTextBoxColumns. when i add the DataGridViewCheckBoxCell as shown here:DataGridViewCheckBoxCell c = new DataGridViewCheckBoxCell();
                    RunTimeCreatedDataGridView.Rows[row].Cells[column] = c; im getting an system.formatExeption:the formatted value of the cell is of the incorrect type. What should i do?