an empty dataset binded in a dataGrid
when the dataGrid is in a form ,it has an empty row,
when the dataGrid is in a MDIForm,it has two rows,why?


using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace WindowsApplication8
{
    /// <summary>
    /// Form1 µÄժҪ˵Ã÷¡£
    /// </summary>
    public class Form1 : System.Windows.Forms.Form
    {
        private System.Windows.Forms.MainMenu mainMenu1;
        private System.Windows.Forms.MenuItem menuItem1;
        private System.Windows.Forms.MenuItem menuItem2;
        /// <summary>
        /// ±ØÐèµÄÉè¼ÆÆ÷±äÁ¿¡£
        /// </summary>
        private System.ComponentModel.Container components = null;

        public Form1()
        {
            //
            // Windows ´°ÌåÉè¼ÆÆ÷Ö§³ÖËù±ØÐèµÄ
            //
            InitializeComponent();

            //
            // TODO: ÔÚ InitializeComponent µ÷ÓúóÌí¼ÓÈκι¹Ô캯Êý´úÂ ë
            //
        }

        /// <summary>
        /// ÇåÀíËùÓÐÕýÔÚʹÓõÄ×ÊÔ´¡£
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if (components != null)
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }

        #region Windows Form Designer generated code
        /// <summary>
        /// Éè¼ÆÆ÷Ö§³ÖËùÐèµÄ·½·¨ - ²»ÒªÊ¹ÓôúÂë±à¼­Æ÷ÐÞ¸Ä
        /// ´Ë·½·¨µÄÄÚÈÝ¡£
        /// </summary>
        private void InitializeComponent()
        {
            this.mainMenu1 = new System.Windows.Forms.MainMenu();
            this.menuItem1 = new System.Windows.Forms.MenuItem();
            this.menuItem2 = new System.Windows.Forms.MenuItem();
            //
            // mainMenu1
            //
            this.mainMenu1.MenuItems.AddRange(new System.Windows.Forms.MenuItem[] {
                                                                                      this.menuItem1});
            //
            // menuItem1
            //
            this.menuItem1.Index = 0;
            this.menuItem1.MenuItems.AddRange(new System.Windows.Forms.MenuItem[] {
                                                                                      this.menuItem2});
            this.menuItem1.Text = "test";
            //
            // menuItem2
            //
            this.menuItem2.Index = 0;
            this.menuItem2.Text = "111";
            this.menuItem2.Click += new System.EventHandler(this.menuItem2_Click);
            //
            // Form1
            //
            this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
            this.ClientSize = new System.Drawing.Size(292, 273);
            this.IsMdiContainer = true;
            this.Menu = this.mainMenu1;
            this.Name = "Form1";
            this.Text = "Form1";
            this.WindowState = System.Windows.Forms.FormWindowState.Maximized;
            this.Load += new System.EventHandler(this.Form1_Load);

        }
        #endregion

        /// <summary>
        /// Ó¦ÓóÌÐòµÄÖ÷Èë¿Úµã¡£
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.Run(new Form1());
        }

        private void Form1_Load(object sender, System.EventArgs e)
        {

        }

        private void menuItem2_Click(object sender, System.EventArgs e)
        {
                        //Èç¹ûÓÃÕâ¶Î³ÌÐòDATAGRIDÖÐÖ»ÓÐÒ »¸ö¿ÕÐÐ
            //Form2 myform = new Form2();
            //myform.Show();


                        //ÓÃÕâ¶Î³ÌÐòDATAGRIDÖÐÓÐÁ½¸ö¿ÕÐ Ð
            Form2 newMDIChild = new Form2();
            newMDIChild.MdiParent = this;
            newMDIChild.Show();
        }
    }
}



using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Data.SqlClient;

namespace WindowsApplication8
{
    /// <summary>
    /// Form2 µÄժҪ˵Ã÷¡£
    /// </summary>
    public class Form2 : System.Windows.Forms.Form
    {
        /// <summary>
        /// ±ØÐèµÄÉè¼ÆÆ÷±äÁ¿¡£
        /// </summary>
        private System.ComponentModel.Container components = null;

        public Form2()
        {
            //
            // Windows ´°ÌåÉè¼ÆÆ÷Ö§³ÖËù±ØÐèµÄ
            //
            InitializeComponent();

            //
            // TODO: ÔÚ InitializeComponent µ÷ÓúóÌí¼ÓÈκι¹Ô캯Êý´úÂ ë
            //
        }

        /// <summary>
        /// ÇåÀíËùÓÐÕýÔÚʹÓõÄ×ÊÔ´¡£
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if(components != null)
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }

        #region Windows Form Designer generated code
        /// <summary>
        /// Éè¼ÆÆ÷Ö§³ÖËùÐèµÄ·½·¨ - ²»ÒªÊ¹ÓôúÂë±à¼­Æ÷ÐÞ¸Ä
        /// ´Ë·½·¨µÄÄÚÈÝ¡£
        /// </summary>
        private void InitializeComponent()
        {
            //
            // Form2
            //
            this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
            this.ClientSize = new System.Drawing.Size(292, 273);
            this.Name = "Form2";
            this.Text = "Form2";
            this.Load += new System.EventHandler(this.Form2_Load);

        }
        #endregion

        private void Form2_Load(object sender, System.EventArgs e)
        {
            DataGrid dataGrid = new DataGrid();
            String mySqlStmt =
                "select top 10 CustomerID,CompanyName,ContactName,"+
                "ContactTitle from Customers where CustomerID='1'";
            String myConString =
                "server=localhost;database=Northwind;uid=sa;pwd=;" ;

            System.Data.SqlClient.SqlDataAdapter myDataAdapter =
                new System.Data.SqlClient.SqlDataAdapter(mySqlStmt,myC onString);
            DataSet myDataSet = new DataSet();

            myDataAdapter.Fill(myDataSet,"dataGrid1");
            dataGrid.SetDataBinding(myDataSet,"dataGrid1");


            Controls.Add(dataGrid);
            dataGrid.Height=500;
            dataGrid.Width=700;

        }
    }
}