标签：c winforms invoke

下面的MessageBox.Show调用显示“内部”.这是一个错误吗？

private void Throw()
{
    Invoke(new Action(() =>
    {
        throw new Exception("Outer", new Exception("Inner"));
    }));
}

private void button1_Click(object sender, EventArgs e)
{
    try
    {
        Throw();
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message); // Shows "Inner"
    }
}

解决方法:

我看了一下System.Windows.Forms.Control的参考源,处理Invoke的代码如下所示：

try {
    InvokeMarshaledCallback(current);
}
catch (Exception t) {
    current.exception = t.GetBaseException();
}

GetBaseException：

public virtual Exception GetBaseException() 
{
    Exception inner = InnerException;
    Exception back = this;

    while (inner != null) {
        back = inner;
        inner = inner.InnerException;
    }

    return back;
}

显然它就像设计一样.来源中的评论没有解释为什么他们这样做.

编辑：一些现在已经消失的网站声称这条评论来自微软的一个人：

Based on the winform comfirmation in the record, our analysis is
correct of the root cause and this behavior is intended. The reason was to
prevent the user from seeing too much of the Windows.Forms internal mechanisms.
This is because the winform’s default error dialog also leverages Application.ThreadException to show the exception details. .Net Winform
team trims the other exceptions information so that the default error
dialog will not display all the details to the end user.

Also, some MSFTs have sugguested to change this behavior. However, .Net
Winform team thinks that changing the exception to throw is a breaking
change and for this reason WinForms will keep sending the innermost exception to the Application.ThreadException handler.

标签：c,winforms,invoke
来源： https://codeday.me/bug/20190519/1138301.html

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