如何访问文本框,使用asp.net Web表单从代码后面的更新面板内标签

Question

我在更新面板中定义了一些绑定到转发器控件的控件.我需要隐藏并显示基于匿名字段的用户名和国家/地区,但问题是我无法以编程方式访问更新面板中定义的控件.

我怎样才能访问这些控件,我也在网上查看但找不到很多引用

下面是aspx页面和.cs页面的代码

<asp:UpdatePanel ID="updPnlComments" runat="server">
<ContentTemplate>
<table border="0" width="100%" ><tr><td valign="top">
    <asp:Repeater ID="rptCommentList" runat="server" EnableViewState="false">
       <ItemTemplate>
            <div id="divComPostDate" class="ArticlePubDate">
                <asp:Label ID="lblComDateAdded" runat="server" Text="Added"></asp:Label> 
                <asp:Label ID="lblComPostDate" runat="server" Text='<%# FormatCommentDate(Eval("comPostDate")) %>'></asp:Label>
            </div>
            <div id="divComMSGDetail" class="PostCommentMSG">
                <asp:Label ID="lblComMSGDetails"  runat="server" Text='<%# Eval("comMessage") %>'></asp:Label> 
            </div>
            <div id="divComUserName" class="ComUserName">
                <asp:Label ID="lblComUserName" runat="server" Text='<%# Eval("comFullName") %>'></asp:Label>,
                <asp:Label ID="lblComCountry" runat="server" Text='<%# Eval("comCountry") %>'></asp:Label>
                <asp:Label ID="lblUserAnonymous" runat="server" Text='<%# showUserName(Eval("comAnonymous")) %>' Visible=false></asp:Label>
            </div>
            <div id="divThinlLine" class="ThinLine" ></div>
        </ItemTemplate>
     </asp:Repeater>
  </td></tr><tr><td>
    <table border="0" width="90%" ><tr><td align="center" valign="bottom" height="50px">
      <table border="0"><tr><td align="center" >
             <uc1:PagerControl ID="PagerControl1" runat="server"  CssClass="gold-pager"  PageMode="LinkButton"  />
      </td></tr></table>
    </td></tr></table>
</td></tr></table>
</ContentTemplate>
</asp:UpdatePanel>

代码背后

protected string FormatCommentDate(object dt)
{
    string date;
    date  = String.Format("{0:hh:mm, MMMM dd, yyyy}", dt);
    return date;
}

protected string showUserName(object userName)
{
    String str=null;
    try
    {
        Boolean isUserAnonymous = Convert.ToBoolean(userName);

        if (isUserAnonymous == true)
        {
            // Not able to access lblComUserName CONTROL here

        }

    }
    catch (Exception ex)
    {

    }

    return str;

}

功能使用Pager和Repeater控件绑定转发器控件

protected void getCommentsList(int iArticleID)
{
    try
    {

        PagerControl1.PageSize = 4;
        //PagerControl1.TotalItems = 1;
        //PagerControl1.PageMode = 4;
        PagerControl1.DisplayEntriesCount = 5;
        //Will show 2 links after ...
        PagerControl1.EdgeEntriesCount = 0;
        DataSet ds = DataProvider.GetCommentList(iArticleID);
        DataView dv = ds.Tables[0].DefaultView;

        //pass the datatable and control to bind
        PagerControl1.BindDataWithPaging(rptCommentList, dv.Table);

    }
    catch (Exception ex)
    {
        HttpContext.Current.Response.Redirect("Message.aspx?msg=Invalid Request");
    }

Answer 1

问题不在于UpdatePanel，而在于Repeater。更新面板内的控件可以在页面范围内直接访问（例如转发器本身），而转发器内的控件必须在绑定期间或之后“找到”。转发器中的代码是许多项目的模板，而不是特定于任何一项。

我建议ItemDataBound向中继器添加一个事件，并在每个项目绑定到中继器时执行该事件内的逻辑。

<asp:Repeater ID="rptCommentList" runat="server" EnableViewState="false"
     OnItemDataBound="rptCommentList_ItemDataBound">

 

protected void rptCommentList_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) 
    {
        // get the data item
        MyObject myObject = (MyObject)e.Item.DataItem;

        // find the label
        Label lblComUserName = (Label)e.Item.FindControl("lblComUserName");

        // do the magic!
        if (myObject.comAnonymous)
             lblComUserName.Visible = false;
    }
}

显然，请替换MyObject为您首先绑定到转发器的集合/列表/表的对象类型。

希望有帮助。