绑定具有两列的表中的组合框

如何连接这些数据，或者有更好的方法？

数据联接accountID - accountname时的示例

          public void BindData()
          {
                cn.Open();
                string strCmd = "select accountID from MsAccount";
                string strCmd2 = "select accountName from MsAccount";
                SqlCommand cmd = new SqlCommand(strCmd, cn);
                SqlCommand cmd2 = new SqlCommand(strCmd2, cn);
                SqlDataAdapter da = new SqlDataAdapter(strCmd, cn);
                SqlDataAdapter da2 = new SqlDataAdapter(strCmd2, cn);
                DataTable dt = new DataTable();
                DataTable dt2 = new DataTable();
                da.Fill(dt);
                da2.Fill(dt2);
                comboBox1.DataSource = dt;
                comboBox1.ValueMember = "AccountID";
                comboBox1.DataSource = dt2;
                comboBox1.ValueMember =  "accountName";
                comboBox1.DisplayMember = "AccountID"+ "-"+"accountName";<<OUTPUT that i need
                //comboBox1.DisplayMember = "accountName";
                comboBox1.Enabled = true;
                comboBox2.Enabled = true;
                cmd.ExecuteNonQuery();
                cn.Close();
           }

   SELECT 
         accountID, 
         (CAST(accountID AS VARCHAR(10))+'-'+accountName) AS accountName 
    FROM 
         MsAccount

public void BindData()
          {
                cn.Open();
                string strCmd = "SELECT accountID, (CAST(accountID AS VARCHAR(10))+'-'+accountName) AS accountName FROM MsAccount";
                SqlCommand cmd = new SqlCommand(strCmd, cn);
                SqlDataAdapter da = new SqlDataAdapter(strCmd, cn);
                DataTable dt = new DataTable();
                da.Fill(dt);
                comboBox1.DataSource = dt;
                comboBox1.ValueMember = "accountID";
                comboBox1.DisplayMember =  "accountName";
                comboBox1.Enabled = true;
                cn.Close();
           }