我想用DataGrid表格实现编辑功能，我也用了VS中DataGrid/属性生成器/列/按钮列/编辑，并填写以下代码：
Imports System.Data.OleDb
    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        zhangmin() '在此处放置初始化页的用户代码
    End Sub

   Private Sub zhangmin()
        Dim ConnString As String
        Dim strSql As String

        ConnString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source="
        ConnString += Server.MapPath("22.mdb")
        strSql = " select * from mima " 'where 学号='" & xuehao.Text & "'"
        Dim Da As New OleDbDataAdapter(strSql, ConnString)
        Dim Ds As New DataSet
        Da.Fill(Ds, "mima")
        DataGrid1.DataSource = Ds.Tables(0)
        DataGrid1.DataBind()
        Ds.Dispose()
        Da.Dispose()
    End Sub

      Private Sub DataGrid1_EditCommand(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridCommandEventArgs) Handles DataGrid1.EditCommand
        DataGrid1.EditItemIndex = e.Item.ItemIndex
        zhangmin()
    End Sub
End Class
却点击无反应，好像代码根本不起作用。为什么？