点击Update之后，更新不了数据。。。用Response.Write写出来后，却是如下面的样子。
void dg_Update(Object Sender,DataGridCommandEventArgs e)
{
datacon();
OleDbCommand thisCOMD=thisCN.CreateCommand();
thisCOMD.CommandText="Update students set class=@class,sex=@sex where id=@no";
thisCOMD.Parameters.Add("@class",((TextBox)e.Item.Cells[1].Controls[0]).Text);
thisCOMD.Parameters.Add("@class",((TextBox)e.Item.Cells[2].Controls[0]).Text);
thisCOMD.Parameters.Add("@no",((TextBox)e.Item.Cells[0].Controls[0]).Text);//id放在表格的第一列。
thisCOMD.Parameters["@no"].Value =dg.DataKeys [e.Item.ItemIndex];
Response.Write(""+thisCOMD.CommandText+"");//这句在浏览器中写出来的是：Update students set class=@class,sex=@sex where id=@no.
try
{
thisCOMD.ExecuteNonQuery();
}
catch
{
Response.Write("Sorry!");
}
thisCN.Close();
}

void dg_Update(Object Sender,System.Web.UI.WebControls.DataGridCommandEventArgs e)
{
datacon();
OleDbCommand thisCOMD=thisCN.CreateCommand();
thisCOMD.Parameters.Add("@no",((TextBox)e.Item.Cells[0].Controls[0]).Text);
thisCOMD.Parameters.Add("@class",((TextBox)e.Item.Cells[1].Controls[0]).Text);
thisCOMD.Parameters.Add("@sex",((TextBox)e.Item.Cells[2].Controls[0]).Text);
thisCOMD.Parameters["@no"].Value=dg.DataKeys[e.Item.ItemIndex];
thisCOMD.CommandText="Update students set mys=@mys,sex=@sex where id=@no";
try
{
thisCOMD.ExecuteNonQuery();
}
catch
{
Response.Write("Sorry");
Response.Write(""+thisCOMD.CommandText+"");
Response.Write(""+e.Item.ItemIndex+"");
}
finally
{
thisAdapter=new OleDbDataAdapter("Select * from students",thisCN);
thisDS=new DataSet();
thisAdapter.Fill(thisDS,"students");
dg.DataSource=thisDS;
dg.DataBind();
dg.EditItemIndex=-1;
}
thisCN.Close();
}

问题已解决，，谢谢大家，，