如何在WinForm组件的UI线程上调用？ [英] How to invoke on the UI thread of a WinForm Component?

问题描述

我正在编码一个WinForm组件，在其中我启动一个Task来进行实际的处理并在延续中捕获异常。从那里，我想在UI元素上显示异常消息。

I'm coding a WinForm component where I start a Task to do the actual processing and trap the exception on a continuation. From there I want to show the exception message on a UI element.

Task myTask = Task.Factory.StartNew (() => SomeMethod(someArgs));
myTask.ContinueWith (antecedant => uiTextBox.Text = antecedant.Exception.Message,
                     TaskContinuationOptions.OnlyOnFaulted);

现在，我遇到了跨线程异常，因为该任务试图从a更新UI元素，显然是非UI线程。

Now I get a cross-thread exception because the task is trying to update a UI element from a, obviously, non UI thread.

但是，在Component类中没有定义Invoke或BeginInvoke。

However, there is no Invoke or BeginInvoke defined in the Component class.

更新

此外，请注意，由于Component不提供，Invoke / BeginInvoke / InvokeRequired在我的Component派生类中不可用。

Also, please note that Invoke/BeginInvoke/InvokeRequired are not available from my Component-derived class since Component doesn't provide them.

推荐答案

您可以在组件中添加一个属性，允许客户端设置一个表单引用，您可以使用该表单引用来调用其BeginInvoke（）方法。

You could just add a property to your component, allows the client to set a form reference that you can use to call its BeginInvoke() method.

这也可以自动完成，最好不要让任何人忘记。这需要一点不可思议的设计时间魔力。我自己没有提出这个建议，而是从ErrorProvider组件中获得的。值得信赖的消息来源等等。将此粘贴到您的组件源代码中：

That can be done automatically as well, preferable so nobody can forget. It requires a bit of design time magic that's fairly impenetrable. I didn't come up with this by myself, I got it from the ErrorProvider component. Trusted source and all that. Paste this into your component source code:

using System.Windows.Forms;
using System.ComponentModel.Design;
...
    [Browsable(false)]
    public Form ParentForm { get; set; }

    public override ISite Site {
        set {
            // Runs at design time, ensures designer initializes ParentForm
            base.Site = value;
            if (value != null) {
                IDesignerHost service = value.GetService(typeof(IDesignerHost)) as IDesignerHost;
                if (service != null) this.ParentForm = service.RootComponent as Form;
            }
        }
    }

设计器自动设置ParentForm当用户将您的组件放在窗体上时，此属性。使用ParentForm.BeginInvoke（）。

The designer automatically sets the ParentForm property when the user drops your component on a form. Use ParentForm.BeginInvoke().

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