WPF Controls does not supported Control. invokeRequired Property

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VS2010

hi guys , in Windows application and i can use if(AnyControl.invokeRequired) .. do some thing
but here in WPF can not found this property
any one help my to convert this Code into WPF Code
the code is :

C#

void buffer_TimedOut(String value)
{
    if (this.InvokeRequired)
    {
        this.BeginInvoke(new Action<String>(buffer_TimedOut), new Object[] { value });
    }
    else
    {
        if (value.Length == 13)
        {
    // Barcode!
        }
        else
        {
            // Typed text...append to Textbox f.e.
        }
    }

any one help me in doing that ... thanks

Posted 14-Sep-12 11:45am

Yasser El Shazly

Updated 14-Sep-12 11:51am

v2

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Comments

[no name] 14-Sep-12 17:52pm

Use the Dispatcher

Sergey Alexandrovich Kryukov 14-Sep-12 18:23pm

Why did you use InvokeRequired even in the original code? In most cases, there is no need.
--SA

Yasser El Shazly 14-Sep-12 18:24pm

how can you convert my code using Dispatcher sorry i am new in using dispatcher and threading

Yasser El Shazly 14-Sep-12 18:25pm

so what should i use Sergey ?

Sergey Alexandrovich Kryukov 14-Sep-12 19:34pm

Didn't Wes and I answered? Please see my answer and ask if you have any further questions; or accept it formally (green button), OK?
--SA

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Sergey Alexandrovich Kryukov · Accepted Answer · 2012-09-14T12:22:00

Solution 1

For most applications, you don't need it even in System.Windows.Forms.Control, because this property will always return true if called from any thread other then the UI thread using a control, and in most designs you know that; this property is only used in some method which can be called from either UI or non-UI thread, which is relatively rare.

With WPF, you need to use the class Dispatcher:
http://msdn.microsoft.com/en-us/library/system.windows.threading.dispatcher.aspx[^].

Please see this article which give sufficient introduction:
http://msdn.microsoft.com/en-us/magazine/cc163328.aspx[^].

—SA

Posted 14-Sep-12 12:22pm

Sergey Alexandrovich Kryukov

Comments

[no name] 14-Sep-12 18:52pm

5

Sergey Alexandrovich Kryukov 14-Sep-12 19:32pm

Thank you, Wes.
--SA

Yasser El Shazly 14-Sep-12 21:05pm

so it will converted like that
if (this.Dispatcher.CheckAccess())
{
try
{
if (value.Length == 13)
{
System.Windows.Forms.MessageBox.Show(Code.ToString());
Code = null;
}
else
{
string temp = this.buffer.Get().ToString();
if (temp.Contains('D'))
{
this.Code += temp[1];
}
else
{
this.Code += temp;
}
}
}
catch
{
// do nothing
}
}
else
{
this.Dispatcher.BeginInvoke(new Action<string>(buffer_TimedOut), new Object[] { value });
}

Sergey Alexandrovich Kryukov 14-Sep-12 22:21pm

Very good. Any problems?
--SA

Yasser El Shazly 15-Sep-12 9:00am

it does not work for me , hey the problem is i am trying to differentiate between barcode key press and keyboard press some one told me i can do that depending up on the speed of reading the code
that is the link of the Example http://codereview.stackexchange.com/questions/15570/differentiate-a-keyboard-scanner-from-keyboard-timeoutbuffer
but it does not differentiate between Keyboard and barcode have you a solution for my problem

Sergey Alexandrovich Kryukov 16-Sep-12 23:43pm

Didn't you misplace this comment? I know the barcode software problem. Did you ask a question on it, too? Your question on thread dispatching was answered, and you are talking about totally different thing. Or are they related?
--SA