儿童通过控制编程LoadControl加载用户控件的时候是空的（类型，对象[]）超负荷 [英] Child Controls are null when loading User Control programmatically via LoadControl(Type, object[]) overload

问题描述

我加载用户控件编程方式是这样的：

I'm loading a user control programatically like this:

        protected void Page_Load(object sender, EventArgs e)
    {
       // LinqDataSource1.TableName = string.Format("{0}s", _table.Context.Mapping.GetMetaType(_type).Name);
       _control = Page.LoadControl(typeof(CatalogoGenerico), new object[] { typeof(CTG_ENT_ENTIDAD) }) as CatalogoGenerico;
       PlaceHolder1.Controls.Add(_control);
    }

与此构造：

        public CatalogoGenerico(Type type):this()
    {
        _db = new DataClasses1DataContext();
        _type = type;

    }

我的问题是，在我的用户控件的所有控件都为空，有没有别的东西，我需要做的加载子控件？

The problem I have is that all the controls in my user controls are null, is there something else I have to do to load the child controls?

推荐答案

这是由设计。一个.ascx文件实际上是从继承code-behind类，所以的.ascx是code隐藏类的派生类型。

This is by design. An .ascx file actually inherits from the code-behind class, so the .ascx is a derived type of the code-behind class.

这意味着，当你使用 LoadControl加载父code-behind类（类型，对象[]）方法，它的实例中定义的父类在code-后面，而不是派生的.ascx类，它包含的子控件。

This means that when you load the parent code-behind class using the LoadControl(Type, object[]) method, it's instantiating the parent class defined in the code-behind, and not the derived .ascx class which contains the child controls.

如果您使用 Page.LoadControl（串）过载，它将工作如你所愿，因为它可以正确地找到模板，找到编译的.ascx类，并加载它。

If you use the Page.LoadControl(string) overload, it will work as you wish, as it can properly find the template, find the compiled .ascx class, and load it.

另一种方法是使用code-背后，而不是标记来实例化您的.ascx文件的所有控件。

The other alternative is to instantiate all the controls in your .ascx file by using the code-behind instead of the markup.

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