未找到儿童控制。 [英] Child control not found.

问题描述

Hello Friends，



我有一个嵌套在父控件中的子控件。



例如：



1>我使用了详细视图控件。

2>我想自定义寻呼机，所以我做了类似下面的事情：

Hello Friends,

I have a child control nested within a parent control.

For example:

1>I used a details view control.
2>I wanted to customize the pager, so i did something like below:

<asp:DetailsView ID="dv" runat="server">
     <PagerTemplate>
        <asp:CheckBoxList ID="cbl"  ToolTip="hi" runat="server" />
     </PagerTemplate>
    </asp:DetailsView>

现在我想访问CheckBoxList按钮单击的事件处理程序。所以在按钮的事件处理程序中，我做了：

Now i wanted to access the CheckBoxList in a button click's event handler. So in the event handler of the button, i did:

CheckBoxList cbl = (CheckBoxList)(dv.FindControl("cbl"));

这里我应用了一个断点，我发现cbl原来是空。



我又尝试了一件事：

here i applied a break point, i observed that "cbl" turned out to be "null".

I tried one more thing:

foreach (Control c in dv.Controls)
      {
          if (c is CheckBoxList)
          {
              Response.Write("true");
          }
      }

再次我在

again i applied a break point on

Response.Write("true");

这是在if内，它不会执行。



然后我试过：

this is within the "if", it does not execute.

then i tried:

CheckBoxList cbl = (CheckBoxList)dv.BottomPagerRow.Cells[0].FindControl("cbl");

再次cbl为空。



最后，我试过了：

again "cbl" is null.

finally, i tried:

CheckBoxList cbl = (CheckBoxList)Page.FindControl("cbl");

cbl再次为空。





我不明白，为什么那个控件空？





有什么建议？



谢谢和问候，

Rahul

"cbl" is null again.


I cant understand, why is that control "null"?


any suggestions?

Thanks and regards,
Rahul

推荐答案

这是范围问题搜索。请参阅： http://msdn.microsoft.com/en-us /library/31hxzsdw%28v=vs.110%29.aspx [ ^ ]。

It's the matter of the scope of the search. Please see: http://msdn.microsoft.com/en-us/library/31hxzsdw%28v=vs.110%29.aspx[^].

MSDN 说：

方法搜索只有页面的直接或顶级容器;它不会递归地搜索页面中包含的命名容器中的控件。要访问从属命名容器中的控件，请调用该容器的FindControl方法。

The method searches only the page's immediate, or top-level, container; it does not recursively search for controls in naming containers contained on the page. To access controls in a subordinate naming container, call the FindControl method of that container.

有关 Control.FindControl 的信息。以下是您可以执行的操作：如果您只有搜索的顶级上下文，则某些 Page ：获取其所有控件：http://msdn.microsoft.com/en-us/library/system.web .ui.control.controls％28v = vs.110％29.aspx [ ^ ]。



然后，对于每个控件，使用它你可以使用上面引用的相同 Control 属性作为页面也是控制。递归地执行：

Thes same is told about Control.FindControl. Here is what you can do: if your have only the top context of the search, some Page: get all its controls: http://msdn.microsoft.com/en-us/library/system.web.ui.control.controls%28v=vs.110%29.aspx[^].

Then, for each control, use its you can use the same Control property referenced above, as the page is also Control. Do it recursively:

class SomeType {

     static Control FindControl(Control control, string id) {
        if (control.ID == id) return control;
        if (control.FindControl(id) != null) return control;
        foreach(Control child in control.Controls) {
            Control foundControl = child.FindControl(id);
            if (foundControl != nill)
                return foundControl;
        }
        return null;
    }

    //...

    void SomeMethod() {
        Control requiredControl = FindControl(Page, "cbl");
    }

} //class SomeType

祝你好运，

-SA

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