private void searchID_Click_1(object sender, EventArgs e) { SqlConnection conn = new Opreate().conn(); conn.Open(); string strCmd; if (textBox1.Text.Equals("*")) { strCmd = "select * from student"; } else { strCmd = "select * from student where " + comboBox1.Text + " = '" + textBox1.Text + " '"; } //dtGrdViewSearch.Rows.Clear(); SqlDataAdapter myDataAdapter; DataSet myDataSet = new DataSet(); myDataAdapter = new SqlDataAdapter(strCmd, conn); myDataAdapter.Fill(myDataSet, "student"); //dtGrdViewSearch.DataSource = myDataSet.Tables["student"]; dataGridView1.DataSource = myDataSet.Tables["student"]; }