blocks|key|1248751|text|起初，我想知道为什么OP还没有将其中一个响应标记为答案，但在我自己尝试它仍然不起作用后，我更深入地挖掘了一下，发现这个问题比我最初想象的要多得多。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1248752|通过阅读类似的问题可以获得更好的理解：Why+won't+control+update/refresh+mid-process|offset|length|1248753|最后，为了记录，我能够通过执行以下操作来更新我的标签：|1248754|private+void+SetStatus(string+status)+
{
++++lblStatus.Text+=+status;
++++lblStatus.Invalidate();
++++lblStatus.Update();
++++lblStatus.Refresh();
++++Application.DoEvents();
}|code-block|syntax|javascript|1248755|尽管据我所知，这远不是一种优雅和正确的方法。这是一种黑客攻击，它可能会工作，也可能不会工作，这取决于线程的繁忙程度。|1248756|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/2341731/why-wont-control-update-refresh-mid-process^0|0|J|18|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@$D|Y|E|Z|1|10]]|A|$]]|$1|F|3|G|5|6|7|11|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|12|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

At first I wondered why the OP hadn't already marked one of the responses as the answer, but after trying it myself and still have it not work, I dug a little deeper and found there's much more to this issue then I'd first supposed. 

A better understanding can be gained by reading from a similar question: <a href="https://stackoverflow.com/questions/2341731/why-wont-control-update-refresh-mid-process">Why won&#39;t control update/refresh mid-process</a>

Lastly, for the record, I was able to get my label to update by doing the following:

<pre><code>private void SetStatus(string status) 
{
 lblStatus.Text = status;
 lblStatus.Invalidate();
 lblStatus.Update();
 lblStatus.Refresh();
 Application.DoEvents();
}
</code></pre>

Though from what I understand this is far from an elegant and correct approach to doing it. It's a hack that may or may not work depending upon how busy the thread is.

blocks|key|1463386|text|在设置标签后调用Application.DoEvents()，但您应该在单独的线程中执行所有工作，以便用户可以关闭窗口。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1463387|entityMap^0|8|M|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

Call <code>Application.DoEvents()</code> after setting the label, but you should do all the work in a separate thread instead, so the user may close the window.

blocks|key|1463671|text|如果您只需要更新几个控件，那么.update()就足够了。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1463672|btnMyButton.BackColor=Color.Green;+//+it+eventually+turned+green,+after+a+delay
btnMyButton.Update();+//+after+I+added+this,+it+turned+green+quickly|code-block|syntax|javascript|1463673|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you only need to update a couple controls, .update() is sufficient.

<pre><code>btnMyButton.BackColor=Color.Green; // it eventually turned green, after a delay
btnMyButton.Update(); // after I added this, it turned green quickly
</code></pre>

blocks|key|1248706|text|你可以试试这个|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1248707|using+System.Windows.Forms;+//+u+need+this+to+include.

MethodInvoker+updateIt+=+delegate
++++++++++++++++{
++++++++++++++++++++this.label1.Text+=+"Started...";
++++++++++++++++};
this.label1.BeginInvoke(updateIt);|code-block|syntax|javascript|1248708|看看它能不能用。|1248709|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

you can try this

<pre><code>using System.Windows.Forms; // u need this to include.

MethodInvoker updateIt = delegate
 {
 this.label1.Text = "Started...";
 };
this.label1.BeginInvoke(updateIt);
</code></pre>

See if it works.

blocks|key|1463551|text|更新UI后，启动一个任务来执行长时间运行的操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1463552|label.Text+=+"Please+Wait...";

Task<string>+task+=+Task<string>.Factory.StartNew(()+=>
{
++++try
++++{
++++++++SomewhatLongRunningOperation();
++++++++return+"Success!";
++++}
++++catch+(Exception+e)
++++{
++++++++return+"Error:+"+%2B+e.Message;
++++}
});
Task+UITask+=+task.ContinueWith((ret)+=>
{
++++label.Text+=+ret.Result;
},+TaskScheduler.FromCurrentSynchronizationContext());|code-block|syntax|javascript|1463553|这在.NET+3.5及更高版本中有效。|1463554|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

After updating the UI, start a task to perform with the long running operation:

<pre><code>label.Text = "Please Wait...";

Task&lt;string&gt; task = Task&lt;string&gt;.Factory.StartNew(() =&gt;
{
 try
 {
 SomewhatLongRunningOperation();
 return "Success!";
 }
 catch (Exception e)
 {
 return "Error: " + e.Message;
 }
});
Task UITask = task.ContinueWith((ret) =&gt;
{
 label.Text = ret.Result;
}, TaskScheduler.FromCurrentSynchronizationContext());
</code></pre>

This works in .NET 3.5 and later.

blocks|key|1463434|text|很容易想要“修复”这个问题并强制UI更新，但最好的修复方法是在后台线程上执行此操作，而不是占用UI线程，这样它仍然可以响应事件。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1463435|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

It's very tempting to want to "fix" this and force a UI update, but the best fix is to do this on a background thread and not tie up the UI thread, so that it can still respond to events.

blocks|key|1463458|text|尝试调用label.Invalidate()|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1463459|http://msdn.microsoft.com/en-us/library/system.windows.forms.control.invalidate(VS.80).aspx|offset|length|1463460|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|2J|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@$D|O|E|P|1|Q]]|A|$]]|$1|F|3|-4|5|6|7|R|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|C]]]]

Try calling label.Invalidate()

<a href="http://msdn.microsoft.com/en-us/library/system.windows.forms.control.invalidate(VS.80).aspx" rel="nofollow noreferrer">http://msdn.microsoft.com/en-us/library/system.windows.forms.control.invalidate(VS.80).aspx</a>

blocks|key|1463632|text|我想我有答案了，从上面提炼出来的，再做一点实验。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1463633|progressBar.Value+=+progressBar.Maximum+-+1;
progressBar.Maximum+=+progressBar.Value;|code-block|syntax|javascript|1463634|我尝试递减该值，即使在调试模式下，屏幕也会更新，但这对于将progressBar.Value设置为progressBar.Maximum无效，因为您不能将进度条值设置为大于最大值，因此我首先将progressBar.Value设置为progressBar.Maximum+-1，然后将progressBar.Maxiumum设置为等于progressBar.Value。有时我想杀了比尔·盖茨或现在是谁的人:o)。|offset|length|style|CODE|1463635|有了这个结果，我看起来甚至不需要Invalidate()、Refresh()、Update()，或者对进度条、它的面板容器或父窗体做任何操作。|1463636|entityMap^0|0|0|T|H|1D|J|2O|H|38|L|3Y|K|4N|G|0|G|C|T|9|13|8|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]|$I|V|J|W|K|L]|$I|X|J|Y|K|L]|$I|Z|J|10|K|L]|$I|11|J|12|K|L]|$I|13|J|14|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|15|8|@$I|16|J|17|K|L]|$I|18|J|19|K|L]|$I|1A|J|1B|K|L]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|1C|8|@]|9|@]|A|$]]]|P|$]]

Think I have the answer, distilled from the above and a little experimentation.

<pre><code>progressBar.Value = progressBar.Maximum - 1;
progressBar.Maximum = progressBar.Value;
</code></pre>

I tried decrementing the value and the screen updated even in debug mode, but that would not work for setting <code>progressBar.Value</code> to <code>progressBar.Maximum</code>, because you cannot set the progress bar value above the maximum, so I first set the <code>progressBar.Value</code> to <code>progressBar.Maximum -</code>1, then set <code>progressBar.Maxiumum</code> to equal <code>progressBar.Valu</code>e. They say there is more than one way of killing a cat. Sometimes I'd like to kill Bill Gates or whoever it is now :o).

With this result, I did not even appear to need to <code>Invalidate()</code>, <code>Refresh()</code>, <code>Update()</code>, or do anything to the progress bar or its Panel container or the parent Form.

In WinForms, how do I force an immediate UI update from UI thread? 

What I'm doing is roughly:

<pre><code>label.Text = "Please Wait..."
try 
{
 SomewhatLongRunningOperation(); 
}
catch(Exception e)
{
 label.Text = "Error: " + e.Message;
 return;
}
label.Text = "Success!";
</code></pre>

Label text does not get set to "Please Wait..." before the operation.

I solved this using another thread for the operation, but it gets hairy and I'd like to simplify the code.

Force GUI update from UI Thread

在WinForms中，如何从UI线程强制立即更新UI？我所做的大致是：label.Text = "Please Wait..."try {    SomewhatLongRunningOperation(); }catch(Exception e){    label.Text = "Error: " + e.Message;    return;}label.Text = "Success!";

问从UI线程强制GUI更新
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