search code

private void button5_Click(object sender, EventArgs e)
        {
            string column = "";
            string selectionString = "";
            if (radioButton1.Checked == true)
            {
                column = "Id";
            }
            else if (radioButton2.Checked == true)
            {
                column = "Name";
            }
            else if (radioButton3.Checked == true)
            {
                column = "LastName";
            }
            else if (radioButton4.Checked == true)
            {
                column = "GPA";
            }
            selectionString = "select * from StudentTB where "+column+" LIKE  '%" + search_txt.Text + "%'";

            SqlConnection connect = new SqlConnection(connectionString);
            connect.Open();
            SqlDataAdapter DataAdap = new SqlDataAdapter(selectionString, connect);
            DataTable TB = new DataTable();
            DataAdap.Fill(TB);
            dataGridView1.DataSource = TB;
            connect.Close();
        }