DataGrid的数据更新，老是更新不了是怎么回事？

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

if(Request.Cookies["UserID"]==null)
{
Response.Redirect("../inc/login.aspx");
}
else
{
System.Data.OleDb.OleDbDataAdapter mycommand=new System.Data.OleDb.OleDbDataAdapter("select * from CP_GouMai where Isok=false and UserID=" + Request.Cookies["UserID"].Value +" order by id desc",oleDbConnection1);
System.Data.DataSet mydataset=new DataSet();
mycommand.Fill(mydataset,"gouwulan");
DataGrid1.DataSource=mydataset;
DataGrid1.DataMember="gouwulan";
DataGrid1.DataBind();
}
                }这是更新代码
protected void DataGrid1_update(object obj,System.Web.UI.WebControls .DataGridCommandEventArgs e)
{
System.Web.UI.WebControls.TextBox mytextbox;
mytextbox=(System.Web.UI.WebControls.TextBox)(e.Item.Cells[5].Controls[0]);
    System.Data.OleDb.OleDbCommand myup=new System.Data.OleDb.OleDbCommand("update CP_GouMai set [counts]=@counts where id="+ e.Item.Cells[1].Text,oleDbConnection1);
myup.Parameters.Add("@counts",mytextbox.Text );
myup.Connection.Open();
try
{
myup.ExecuteNonQuery();
}
catch(Exception exx)
{


Response.Write(exx.ToString()+"数据库操作失败！");
}
myup.Connection.Close();
DataGrid1.DataBind();
DataGrid1.EditItemIndex=-1;
}
点更新后还是编辑状态。好象没执行到最后一句的DataGrid1.EditItemIndex=-1;