如何使用反射在 WPF 中加载 UserControl? [英] How to load a UserControl in WPF with reflection?

问题描述

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    var assm = Assembly.LoadFrom("wpflib.dll");
    foreach (var t in assm.GetTypes())
    {
        var i = t.GetInterface("test.ILib");
        if (i != null)
        {
            var tmp = Activator.CreateInstance(typeof(UserControl)) as UserControl;
            this.stackPanel1.Children.Add(tmp);
        }
    }
}

tmp(wpflib.dll 中的 UserControl1)只包含一个标签和一个文本框.

tmp(UserControl1 in wpflib.dll) only contains a label and a textbox.

Windows1 (test.exe) 引用 ILib.dll，并且只包含一个 stackPanel1.

Windows1 (test.exe) reference ILib.dll, and only contains a stackPanel1.

但是，为什么 Windows1(stackPanel1) 中没有 nohong?

But, why there is nothong in Windows1(stackPanel1)?

推荐答案

您根本没有从 DLL 实例化类型.而不是:

You are not instantiating the type from the DLL at all. Instead of:

var tmp = Activator.CreateInstance(typeof(UserControl)) as UserControl;

写:

var tmp = Activator.CreateInstance(t) as UserControl;

此外，我建议您实际编写

Furthermore, I would recommend that you actually write

var tmp = (UserControl) Activator.CreateInstance(t);

相反.否则，如果您有错误，稍后您将收到空引用异常，这不是非常有用且难以调试.通过这种方式，您可以在错误实际发生的正确位置获得更有意义的类型转换异常.

instead. Otherwise, if you have a bug, you will get a null-reference exception later on, which is not very informative and hard to debug. This way you get a more meaningful type-cast exception in the right place where the bug actually happens.

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