从母版页访问内容页内用户控件中的值

Question

我在内容页面的用户控件（ascx）中有一个字符串（lang）。 我想从母版页访问（lang）值。 我怎样才能做到这一点？

用户控件（lang.ascx.cs）-后面的代码。

 lang = (string)(Reader["lang"]); //lang is retrieved from a database

用户控件（lang.ascx）。

<input runat="server" type="hidden" ID="langInput" value="<%: lang %>"/>

内容页面（lang.aspx）

<uc:lang runat="server" /> 

现在如何从母版页访问（lang）值？

谢谢。

Answer 1

要找到该控件，您必须执行很多FindControls

//first find the ContentPlaceHolder on the Master page
ContentPlaceHolder contentPlaceHolder = this.FindControl("ContentPlaceHolder1") as ContentPlaceHolder;

//then the PlaceHolder on the aspx page that contains the UserControl
PlaceHolder placeHolder = contentPlaceHolder.FindControl("PlaceHolder1") as PlaceHolder;

//then the UserControl
UserControl userControl = contentPlaceHolder.FindControl("UserControl1") as UserControl;

//and finally the Control we want to manipulate
HiddenField hiddenField = userControl.FindControl("HiddenField1") as HiddenField;

hiddenField.Value = lang;

//or you can you do the same in a single line of code
HiddenField hiddenField = this.FindControl("ContentPlaceHolder1").FindControl("PlaceHolder1").FindControl("UserControl1").FindControl("HiddenField1") as HiddenField;

如果将UserControls动态添加到页面，请不要忘记分配一个ID，否则FindControl将不起作用。

myControl = (MyControl)LoadControl("~/MyControl.ascx");
//do not forget to assign an ID
myControl.ID = "UserControl1";
PlaceHolder1.Controls.Add(myControl);