hi all,

i have a form with a tabcontrol with 4 pages. on the first page are many
controls bound to a database. now i bound the controls of page two (two
multiline textboxes, four SelectedValues) to the db. the program compiles
without an error and runs fine, until i click on tabpage 2. then the program
throws the following exception:

System.ArgumentException: Der Objekttyp kann nicht zum Zieltyp konvertiert
werden. (english: Object type cannot be converted to target type)
at System.Windows.Forms.Control.SetVisibleCore(Boolean value)
at System.Windows.Forms.Control.set_Visible(Boolean value)
at System.Windows.Forms.TabPage.set_Visible(Boolean value)
at System.Windows.Forms.TabControl.UpdateTabSelection(Boolean uiselected)
at System.Windows.Forms.TabControl.OnSelectedIndexChanged(EventArgs e)
at System.Windows.Forms.TabControl.WmSelChange(Message& m)
at System.Windows.Forms.TabControl.WndProc(Message& m)
at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd,
Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.SendMessage(HandleRef hWnd,
Int32 msg, IntPtr wParam, IntPtr lParam)
at System.Windows.Forms.Control.SendMessage(Int32 msg, IntPtr wparam,
IntPtr lparam)
at System.Windows.Forms.Control.ReflectMessageInternal(IntPtr hWnd,
Message& m)
at System.Windows.Forms.Control.WmNotify(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at System.Windows.Forms.ContainerControl.WndProc(Message& m)
at System.Windows.Forms.Form.WndProc(Message& m)
at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd,
Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.CallWindowProc(IntPtr
wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at System.Windows.Forms.NativeWindow.DefWndProc(Message& m)
at System.Windows.Forms.Control.DefWndProc(Message& m)
at System.Windows.Forms.Control.WmMouseDown(Message& m, MouseButtons
button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.TabControl.WndProc(Message& m)
at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd,
Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at
System.Windows.Forms.ComponentManager.System.Windows.Forms.UnsafeNativeMethods+IMsoComponentManager.FPushMessageLoop(Int32
dwComponentID, Int32 reason, Int32 pvLoopData)
at System.Windows.Forms.ThreadContext.RunMessageLoopInner(Int32 reason,
ApplicationContext context)
at System.Windows.Forms.ThreadContext.RunMessageLoop(Int32 reason,
ApplicationContext context)
at System.Windows.Forms.Application.Run(Form mainForm)


there is no line number of my code in the stacktrace, so i don't know where
to look. can anyone help me?

thx for any help
netracer

NetRacer,

Your question has a standard answer that is long time not given.

Put in the top of your program file.
Option Strict On

Probably you will than see the error.
And feel than free to ask when you don't know how to solve that.
(It needs than probably converting or casting)

I hope this helps,

Cor

"Cor Ligthert" <notmyfirstname@planet.nl> schrieb
[quoted text, click to view]


In which file of the source files for System.Windows.Forms.dll?

;-)