for (int i = 0; i < dataGridView1.Rows.Count; i++)
                {
                    if (dataGridView1.Rows[i].Cells["Make"].Value.ToString().ToUpper().Contains("ro"))
                    {
                        dataGridView1.Rows[i].Cells["Make"].Style = new DataGridViewCellStyle() { Font = new Font(dataGridView1.Font, FontStyle.Bold), ForeColor = Color.DodgerBlue };
//it will change cell forecolor you can use according to you required action
// same like forecolor you can change backcolor or cell and also row.
                    }
//ro 
// or you can use textbox value.
                    if (dataGridView1.Rows[i].Cells["Model"].Value.ToString().ToUpper().Contains(txtBox1.Text))
                    {
                        dataGridView1.Rows[i].Cells["Model"].Style = new DataGridViewCellStyle() { Font = new Font(dataGridView1.Font, FontStyle.Bold), ForeColor = Color.DodgerBlue };
 
// for full row colors you can use following
// dataGridView1.Rows[i].DefaultCellStyle = new DataGridViewCellStyle() { Font = new Font(dataGridView1.Font, FontStyle.Bold), ForeColor = Color.DodgerBlue, BackColor = Color.Green };
                    }                   
		}

hi Pravesh Singh

how to filter records gridview dropdownlist using mysql database

what if it does not use SqlDataSource.
I populate and retrieve data from code behind
please help me