ThreadStateException can't handeled in ClipBoard.SetText() Function

Question

1.00/5 (1 vote)

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HI.
When I click the button and run the following code I am unable to resolve the exception.
ThreadStateException was unhandled by user code
"Current thread must be set to single thread apartment (STA) mode before OLE calls can be made. Ensure that your Main function has STAThreadAttribute marked on it."

Any one has the idea??

C#

private void button1_Click(object sender, EventArgs e)
        {
            new Task(myFunction).Start();
        }
        private void myFunction()
        {
            Clipboard.SetText("this text will be copied to clipboard");
        }

Posted 14-Feb-14 10:29am

Asad Nawaz

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3 solutions

Solution 3

Instead of setting the apartment state of the separate thread (which is some cases makes perfect sense, because you may need to use one apartment state in one thread (say, main one) and different in some other thread, to use some API requiring certain apartment state), it doesn't look like you need it in your case.

Instead, you could simply set STA thread for your main thread at the point where you have your entry point method:

C#

using System;

//...

[STAThread]
static void Main( /* ... */  ) {
    //...
}

This way may look not universal enough. It is not. It's just fit most of the cases. Let's see: a console application can start with either STAThread or MTAThread, same thing with System.Windows.Forms, but WPF requires [STAThread]. In other words, in most cases, you cannot go wrong with STAThread. And only in some special cases you many need both.

—SA

Posted 14-Feb-14 13:41pm

Sergey Alexandrovich Kryukov

Comments

Asad Nawaz 15-Feb-14 4:27am

Hi.
I tried this in my case "Windows Form Application."
But Main Function in Program.cs file Already contained.
[STAThread]
static void Main(/*...*/){
}
Even I tries to add [STAThread] to my every function in my program. But not worked. That's why I used the method I have mentioned in my answer.

Sergey Alexandrovich Kryukov 15-Feb-14 6:13am

Really? Then let me ask you: do you have anything with MTAThread at all, anywhere? However, I have to check it up, maybe I forgot the defaults; it's easy to check up. Yes, your solution should work, I used to use this approach in opposite case, when MTAThread was required (speech recognition engine, for example; one of them).
—SA

Solution 1

use clipboard as in the following:

C#

private void button1_Click(object sender, EventArgs e)
        {
            // new Task(myFunction).Start();
            try
            {
                myFunction();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
        }

and take a look here for the thread mechanism. http://msdn.microsoft.com/en-us/library/windows/desktop/ms693344%28v=vs.85%29.aspx[^]

Posted 14-Feb-14 10:58am

Vedat Ozan Oner

Comments

Sergey Alexandrovich Kryukov 14-Feb-14 19:57pm

Please see my comments to Solution 2, where I explain why this is nothing but fake answer and harmful advice.
—SA

Vedat Ozan Oner 15-Feb-14 6:21am

please see the bottom of the page:

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.

Let's work to help developers, not make them feel stupid.

Sergey Alexandrovich Kryukov 15-Feb-14 6:33am

Who makes stupid who? I don't feel too stupid if someone points out my mistakes, and even if I do, I do understand it was my problem, not the problem of the one who pointed out my mistakes.

You certainly can find places where other people find my mistakes. It happens. You won't find place where I "play the offended card" and counter-attack. You are picking quotation inadequate to the situation and try to set yourself beyond criticism.

—SA

Vedat Ozan Oner 15-Feb-14 6:41am

then look at my comment in solution 2, again.

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When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Asad Nawaz · Accepted Answer · 2014-02-14T11:12:00

Solution 2

C#

private void button1_Click(object sender, EventArgs e)
        {
            new Task(myFunction).Start();
        }
private void myFunction()
        {
           RunAsSTAThread(
            () =>
            {
                ClClipboard.SetText("this text will be copied to clipboard");
            });
            
        }

static void RunAsSTAThread(Action goForIt)
        {
            AutoResetEvent @event = new AutoResetEvent(false);
            Thread thread = new Thread(
                () =>
                {
                    goForIt();
                    @event.Set();
                });
            thread.SetApartmentState(ApartmentState.STA);
            thread.Start();
            @event.WaitOne();
        }

Posted 14-Feb-14 11:12am

Asad Nawaz

Comments

Vedat Ozan Oner 14-Feb-14 17:28pm

ok, you can do it in that way. but I don't understand why someone wants to do this like that. are you testing something? and it would be better for you to write a tip about the subject instead of submitting a question, since you know the answer.

Asad Nawaz 14-Feb-14 18:05pm

I researched a lot to for about 2 to 3 hours. After that I found the solution very hardly.
As There was a method in my application that requires large time to finish. when ever I call it in my form. My form was going to not responding mode.
Researched a lot about asynchronous functions calls, delegates etc.
Then some one told for Using Tasks. But my function uses Clipboard in it. So there was an exception.
I again searched and found the solution to call the function using this way.
Any Ways. Thank you so much Vedat OzanOner. You are the only, you tried to answer me ..
:-*
Thank you.

Sergey Alexandrovich Kryukov 14-Feb-14 19:56pm

Asad,

Vedat is, in principle, right. Why asking a question and answering the same? You already knew the answer, so think: who else would be interested in that?
If you really have interesting findings (interesting for others), why not publishing some, say, Tips/Tricks article? Otherwise nothing is needed.

At the same time, your solution is relevant and can work. I doubt you really need to do so though. Please see my answer. But Vedat, while criticizing you, made much worse post. I have no idea why did you tell him that he "tried to answer". He did not. You solution at least can work; and you actually found advanced technique which is good to know... So, I have few more words to this member...

Vedat,

As you can see, I do understand your criticism, buy your own answer is a pure abuse. For anyone who would not know "real" solution but knowing the basics of programming, should be quite clear that your "answer" is a pure fake. If you handle some exception, it does not mean that failure you caught can turn into successful operation. Isn't that obvious? It it totally clear that you did not even try to consider the root cause of the problem. You totally ignored the real problem related to the apartment state. From your answer, we cannot learn anything about working with then, forget addressing the problem related to apartment states.

And what's worse, you actually set a very bad sample of using exception: handling them too locally. Actually, catching and handling exception at the level of a separate method is much worse then not taking care about it at all. Exceptions are designed to be isolated from "normal" instruction flow. They should only be handled at very few strategically selected points. I call them "points of confidence". Also, they should be caught in the main event loop of UI application and on the top stack frame of each stack. If you do what you show in your own work, this must be really bad work.

By your attempt to answer, you only make potential harm, nothing like help. When you answer (and when you criticize others), you should feel responsibility for your doing. It's way too easy to confuse some naive readers, beginners, and direct them in a wrong way.

Thank you for understanding.

—SA

Asad Nawaz 15-Feb-14 4:19am

Hi Segery Alexandrovich Kryulov
you are right as If I know the answer I should post on tipes and trips. I got your point.
But I tried this way that I was unable to find the solution so I have posted my question.
But still researching other side.
After some hours, perhaps some one did't replied with working solution.
After doing research and research I found the solution. So I think it is a really Good Option in CodeProject.com to click "I Solved this My Self".
I never tried post a question for that I know the answer as I think this is really not good. For that I should definately post some article or tips and tricks for other. :)
Thank you Surgey Alexanfovich Kryunkov. You are really an intelligent and nice person. :)

Sergey Alexandrovich Kryukov 15-Feb-14 6:10am

Thank you for your nice words.
Did you consider my answer and try to use this as a simpler option?
—SA

Asad Nawaz 15-Feb-14 7:20am

Yes. I tried that before posting solution. But didn't worked for me.
Thank you :)

Vedat Ozan Oner 15-Feb-14 6:13am

Sergey,
Let me make some points clear. It doesn't make me irresponsible person while trying to help them. I don't claim that I know everything on the subject or anything. I just try to share what I know and I think codeproject is for that purpose, sharing what you know, helping others. If you don't like my suggestion, you can simply downvote it and tell why. This can be understandable. But insulting someone is not a thing which cannot be expected as understandable by the other party.

As a human being, I can make mistakes, what I say may be wrong, which is natural on that earth. I like being criticized which let me learn more. To be criticized, I am taking the risk of being wrong. But you are harming codeproject much more than me by showing such an attitude toward others which makes them irritated when they want to share something.

There are others who knows more than me (and I know you are one of them), and I like to hear your comments, ideas about the subject. But such conversation shouldn't disturb the good mood. Please don't use such big words while criticizing others. I cannot accept being irresponsible or abusive or other blames. You can tell me that I'm wrong, I can happily accept that. But you cannot call me irresponsible. Please be more gentle in your comments.

As you see, I criticized you without insulting you. I hope my suggestion helps you to being a better person.
Thank you for understanding.

Sergey Alexandrovich Kryukov 15-Feb-14 6:29am

Oh, no insults, ever. And thank you for good intentions of your criticism. The main purpose of criticism is to improve things, isn't it? I do understand that you are trying to be responsible, but it means that you need to be more responsible. It was you quick answer, and it is obvious to me that you could understand that the question is not acceptable if your thought more. If you want to argue that you could not see that, it would be perhaps too challenging...

Best wishes,
—SA