ASP：GridView没法进行编辑操作

  
  <asp:GridView ID="GridView1" runat="server"
    AutoGenerateColumns="false" CellPadding="4"
    ForeColor="#003366" GridLines="Both"  OnRowDeleting="GridView1_RowDeleting" OnRowEditing="GridView1_RowEditing"
                        OnRowUpdating="GridView1_RowUpdating" OnRowCancelingEdit="GridView1_RowCancelingEdit">
                        <FooterStyle BackColor="#990000" Font-Bold="True" ForeColor="White" />
     <Columns>
                            <asp:BoundField DataField="name" HeaderText="用户ID"  />
                            <asp:BoundField DataField="subject" HeaderText="用户姓名" />
                            <asp:BoundField DataField="createtime" HeaderText="性别" />
                            <asp:CommandField HeaderText="选择" ShowSelectButton="True" />
                            <asp:CommandField HeaderText="编辑" ShowEditButton="True" />
                            <asp:CommandField HeaderText="删除" ShowDeleteButton="True" />
    </Columns>
                        <RowStyle ForeColor="#000066" />
                        <SelectedRowStyle BackColor="#669999" Font-Bold="True" ForeColor="White" />
                        <PagerStyle BackColor="White" ForeColor="#000066" HorizontalAlign="Left" />
                        <HeaderStyle BackColor="#006699" Font-Bold="True" ForeColor="White" />
    </asp:GridView>

namespace test1
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        MySqlConnection myConnection;
        MySqlCommand myCommand;
        string connectString = "userid=root;pwd=shouneng;host=localhost;database=test1";
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack) {
                bind();
            }
        }
        public void bind() {
            myCommand = new MySqlCommand("select * from teacher");
            myConnection=new MySqlConnection(connectString);
            MySqlDataAdapter myAdapter = new MySqlDataAdapter(myCommand.CommandText, myConnection);
            DataSet myDataSet = new DataSet();
            myAdapter.Fill(myDataSet);
            this.GridView1.DataSource = myDataSet;
            this.GridView1.DataKeyNames =new String[]{ "name"};
            this.GridView1.DataBind();
            myConnection.Close();
        }

        protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
        {
            this.GridView1.EditIndex = -1;
            bind();
        }

        protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
        {
            string command = "delete from teacher where id="+GridView1.DataKeys[e.RowIndex].Value.ToString();
            myCommand = new MySqlCommand(command);
            myConnection = new MySqlConnection(connectString);
            myCommand.ExecuteNonQuery();
            myConnection.Close();
            bind();
        }

        protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
        {
            GridView1.EditIndex = e.NewEditIndex;
            bind();
        }

        protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
        {
            string command = "update teacher set name=" 
                + GridView1.Rows[e.RowIndex].Cells[0].ToString().Trim() + "subject"
                + GridView1.Rows[e.RowIndex].Cells[1].ToString().Trim() + "createtime"
                + GridView1.Rows[e.RowIndex].Cells[2].ToString().Trim();
        }

        public override void VerifyRenderingInServerForm(Control control)
        {
            
        }
    }
}