Hello
I have some Threads, and they write something to
RichTextBox.Tex t property. But sometimes i receive error:
************** Exception Text **************
System.NullRefe renceException: Object reference not set to an instance
of an object.
at System.Windows. Forms.RichTextB ox.EditStreamPr oc(IntPtr dwCookie,
IntPtr buf, Int32 cb, Int32& transferred)
at System.Windows. Forms.UnsafeNat iveMethods.Call WindowProc(IntP tr
wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at System.Windows. Forms.NativeWin dow.DefWndProc( Message& m)
at System.Windows. Forms.Control.D efWndProc(Messa ge& m)
at System.Windows. Forms.Control.W ndProc(Message& m)
at System.Windows. Forms.TextBoxBa se.WndProc(Mess age& m)
at System.Windows. Forms.RichTextB ox.WndProc(Mess age& m)
at System.Windows. Forms.ControlNa tiveWindow.OnMe ssage(Message& m)
at System.Windows. Forms.ControlNa tiveWindow.WndP roc(Message& m)
at System.Windows. Forms.NativeWin dow.Callback(In tPtr hWnd, Int32
msg, IntPtr wparam, IntPtr lparam)
Why ? Is it problem with synchronization : that many threads try to
change Text property at the same time, or what ?
How can i solve this problem ?
Thanx
Michal
1  2131 
vertigo,
if you access any UI control from threads you might have similar problems.
Most of UI controls are single-threaded by definition and you can safely
access them only from UI thread.
HTH
Alex
"vertigo" <ax***@wp.pl> wrote in message
news:cn******** **@nemesis.news .tpi.pl... Hello
I have some Threads, and they write something to
RichTextBox.Tex t property. But sometimes i receive error:
************** Exception Text **************
System.NullRefe renceException: Object reference not set to an instance
of an object.
at System.Windows. Forms.RichTextB ox.EditStreamPr oc(IntPtr dwCookie,
IntPtr buf, Int32 cb, Int32& transferred)
at System.Windows. Forms.UnsafeNat iveMethods.Call WindowProc(IntP tr
wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at System.Windows. Forms.NativeWin dow.DefWndProc( Message& m)
at System.Windows. Forms.Control.D efWndProc(Messa ge& m)
at System.Windows. Forms.Control.W ndProc(Message& m)
at System.Windows. Forms.TextBoxBa se.WndProc(Mess age& m)
at System.Windows. Forms.RichTextB ox.WndProc(Mess age& m)
at System.Windows. Forms.ControlNa tiveWindow.OnMe ssage(Message& m)
at System.Windows. Forms.ControlNa tiveWindow.WndP roc(Message& m)
at System.Windows. Forms.NativeWin dow.Callback(In tPtr hWnd, Int32
msg, IntPtr wparam, IntPtr lparam)
Why ? Is it problem with synchronization : that many threads try to
change Text property at the same time, or what ?
How can i solve this problem ?
Thanx
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