find控件位于内容页面内部

本文关键字：内部 于内容 控件 find | 更新日期: 2023-09-27 18:11:09

我在母版页中使用以下代码来查找内容页中的控件。在第一页加载时，它工作得很好;但是，当我从内容页面上的下拉菜单中选择一个项目并且启用了自动回退时，我会得到错误"对象引用未设置为对象的实例"。这意味着FindControl()函数无法在内容页面中找到控件。这个问题的原因是什么?

PlaceHolder pHolder = (PlaceHolder)ContentPlaceHolder2.FindControl("PlaceHolder1");
Label lblPage = (Label)pHolder.FindControl("lblPageName");
if (lblPage.Text == "DesignSerachSQGrid")
{
}

编辑……下拉菜单的Html代码:

 <telerik:RadComboBox ID="ddlSearchL1" runat="server" Width="400px" Skin="Office2007" 
                    onselectedindexchanged="ddlSearchL1_SelectedIndexChanged" 
                    AutoPostBack="True" Font-Names="Eras Medium ITC" Font-Size="X-Small" 
                    onprerender="ddlSearchL1_PreRender">
                   <Items>
                       <telerik:RadComboBoxItem runat="server" Text="Please Select ................" 
                           Value="Please Select ................" Font-Name="Eras Medium ITC" />
                       <telerik:RadComboBoxItem runat="server" Text="Design Documents" 
                           Value="Design Documents" Font-Name="Eras Medium ITC" />
                       <telerik:RadComboBoxItem runat="server" Text="Vendor Documents" 
                           Value="Vendor Documents" Font-Name="Eras Medium ITC" />
                       <telerik:RadComboBoxItem runat="server" Text="Business Documents" 
                           Value="Business Documents" Font-Name="Eras Medium ITC" />
                       <telerik:RadComboBoxItem runat="server" Text="Management Documents" 
                           Value="Management Documents" Font-Name="Eras Medium ITC" />
                       <telerik:RadComboBoxItem runat="server" Text="Squad Check - Management" 
                           Value="Squad Check - Management" Font-Name="Eras Medium ITC" />
                       <telerik:RadComboBoxItem runat="server" Text="Transmittal - Management" 
                           Value="Transmittal - Management" Font-Name="Eras Medium ITC" />
                           <telerik:RadComboBoxItem runat="server" Text="Transmittal - Design" 
                           Value="Transmittal - Design" Font-Name="Eras Medium ITC" />
                           <telerik:RadComboBoxItem runat="server" Text="Squad Check - Design" 
                           Value="Squad Check - Design" Font-Name="Eras Medium ITC" />
            <telerik:RadComboBoxItem runat="server" Text="Transmittal - Vendor" 
                           Value="Transmittal - Vendor" Font-Name="Eras Medium ITC" />
                           <telerik:RadComboBoxItem runat="server" Text="Squad Check - Vendor" 
                           Value="Squad Check - Vendor" Font-Name="Eras Medium ITC" />
                   </Items>
           </telerik:RadComboBox>

find控件位于内容页面内部

你可以查看这个帖子:. NET 2.0 MasterPages和FindControl()

/// <summary>
/// Finds a Control recursively. Note finds the first match and exists
/// </summary>
/// <param name="ContainerCtl"></param>
/// <param name="IdToFind"></param>
/// <returns></returns>
public static Control FindControlRecursive(Control Root, string Id)
{
    if (Root.ID == Id)
        return Root; 
    foreach (Control Ctl in Root.Controls)
    {
        Control FoundCtl = FindControlRecursive(Ctl, Id);
        if (FoundCtl != null)
            return FoundCtl;
    }
    return null;
}

用它

this.dgItemList = FindControlRecursive(this.Master, "dgItemList") as DataGrid;
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