如何确保InvokeRequired不会中止?

问题描述

这是我的代码:

foreach (var pathCartella in folderList)
{
    try
    {
        // some operation

        if (txtMonitor.InvokeRequired)
        {
            txtMonitor.BeginInvoke(new MethodInvoker(delegate { txtMonitor.AppendText(pathCartella + Environment.NewLine); }));
        }
    }
    catch (Exception err)
    {
        // some operation
        return;
    }
}

但是我注意到，如果我捕获到异常，在所有txtMonitor.InvokeRequired发送到UI之前，return可以采取行动，并且我丢失了一些消息".

but I notice that, if I catch an Exception, return can act before that all txtMonitor.InvokeRequired has been sent to the UI, and I lost some "message".

如何避免这种情况?

推荐答案

如果我正确理解了您的要求，则可以使用try/catch块的第三部分-最后

If I understand your requirements correctly, then you can use the third part of the try/catch block - finally

因此您的代码将更改为以下形式:

So your code would change to something of the form:

foreach (var pathCartella in folderList)
{
    try
    {
        // some operation


    }
    catch (Exception err)
    {
        // some operation
        return;
    }
    finally
    {
        if (txtMonitor.InvokeRequired)
        {
            txtMonitor.BeginInvoke(new MethodInvoker(delegate { txtMonitor.AppendText(pathCartella + Environment.NewLine); }));
        }
    }
}

一些注意事项-您确定只在InvokeRequired是true时才运行它吗?例如，如果您通过简单的按钮单击而不是后台线程运行它，则InvokeRequired将是false，并且代码将永远不会执行.

A couple of notes - are you sure you only want to run it if InvokeRequired is true? If you are running it from a simple button click, for example, and not from a background thread, then InvokeRequired will be false and code will never execute.

如果您想知道是否最终将始终被调用，那么这个特定问题已经被问过很多次了.参见.那有一些有趣的反例.

If you are wondering about whether finally will always be called, then this particular question has been asked many times. See If I return out of a try/finally block in C# does the code in the finally always run? for example. That has some interesting counter-examples.

您可以考虑的另一种选择是简单地throw您的异常.您可以将pathCartella作为错误消息的一部分传递，因此您知道异常发生的路径以及异常是什么.然后，您的呼叫者可以处理此问题.例如:

The other option you could consider is to simply throw your exception. You could pass pathCartella as part of the error message, so you know what path the exception happened on, and what the exception was. Your caller can then handle this. For example:

foreach (var pathCartella in folderList)
{
    try
    {
        // some operation


    }
    catch (Exception err)
    {
        // some operation

        //The original exception becomes the inner exception (so you can get original
        //error and stack trace etc). The new exception message contains the path.
        throw new Exception(
            String.Format("Failed to perform operation on '{0}'", pathCartella),
            err);

    }

}

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