Gridview OnSelectedIndexChanged="ddlrefresh_SelectedIndexChanged"> 的事件永远不触发？

protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            bind();
            
        }
    }

    public void bind()
    {
        string sqlStr = "select * from Employee";
        DataSet myds = Common.dataSet(sqlStr);
        GridView1.DataSource = myds;
        GridView1.DataKeyNames = new string[] { "ID" };
        GridView1.DataBind();

        AccessDataSource s = new AccessDataSource("E:\\WebSite\\GridViewExamples\\GridViewExamples\\App_Data\\Example.mdb", "select * from Employee");
        this.GridView1.DataSourceID = s.ID;
        this.GridView1.DataBind();
    }
   protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e) 
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            DropDownList ddlrefresh = (DropDownList)e.Row.FindControl("ddlRefresh");

            //ddlrefresh.NamingContainer
            ddlrefresh.AutoPostBack = true;
            ddlrefresh.SelectedIndexChanged += new EventHandler(ddlrefresh_SelectedIndexChanged);

        }
    }

    protected void ddlrefresh_SelectedIndexChanged(object sender, EventArgs e)
    {
        ClientScript.RegisterStartupScript(this.GetType(), "script13", "<mce:script type="text/javascript"><!--
alert('ddlrefresh_SelectedIndexChanged')
// --></mce:script>");
    }

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上面这样写dropdownlist 的事件永远不触发？


但是当代码换成

-------------------------------------------------------------------------------------------------------------------------------------<!-- Code highlighting produced by Actipro CodeHighlighter (freeware) http://www.CodeHighlighter.com/ -->

     <asp:TemplateField>
                <ItemTemplate>
                 [color=#FF0000]   <asp:DropDownList ID="ddlRefresh" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddlrefresh_SelectedIndexChanged">[/color]                        <asp:ListItem Value="1">1</asp:ListItem>
                        <asp:ListItem Value="2">2</asp:ListItem>
                        <asp:ListItem Value="3">3</asp:ListItem>
                    </asp:DropDownList>
                </ItemTemplate>
            </asp:TemplateField>

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就会执行。
为什么第一种方法不执行呢？

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解决方法:

 protected void GridView1_RowCreated(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            DropDownList ddlrefresh = (DropDownList)e.Row.FindControl("ddlRefresh");

            //ddlrefresh.NamingContainer
            ddlrefresh.AutoPostBack = true;
            ddlrefresh.SelectedIndexChanged += new EventHandler(ddlrefresh_SelectedIndexChanged);

        }
    }

将事件代码加入到
RowCeated

就行了。