A
Andrus
SWF DataGridView contains combobox control.
Activating combobox and pressing F4 to open dropdown menu causes strange NRE
(see below).
When I enter some valid value to combobox, press tab, shift+tab , 44
dropdown menu opens OK.
How to fix ?
How to use VCSE 2008 with .net framework source code to find the line in
System.Windows.Forms.DataGridViewComboBoxCell.ComboBox_DropDown()
which causes this error ?
Andrus.
System.NullReferenceException was unhandled
Message="Object reference not set to an instance of an object."
Source="System.Windows.Forms"
StackTrace:
at
System.Windows.Forms.DataGridViewComboBoxCell.ComboBox_DropDown(Object
sender, EventArgs e)
at System.EventHandler.Invoke(Object sender, EventArgs e)
at System.Windows.Forms.ComboBox.OnDropDown(EventArgs e)
at myApp.myComboBox.OnDropDown(EventArgs e) in myComboBox.cs:line 71
at System.Windows.Forms.ComboBox.WmReflectCommand(Message& m)
at System.Windows.Forms.ComboBox.WndProc(Message& m)
at
System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.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.WmCommand(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at
System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.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.ComboBox.DefChildWndProc(Message& m)
at System.Windows.Forms.ComboBox.ChildWndProc(Message& m)
at
System.Windows.Forms.ComboBox.ComboBoxChildNativeWindow.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.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32
dwComponentID, Int32 reason, Int32 pvLoopData)
at
System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32
reason, ApplicationContext context)
at
System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason,
ApplicationContext context)
at System.Windows.Forms.Application.Run(Form mainForm)
.....
Activating combobox and pressing F4 to open dropdown menu causes strange NRE
(see below).
When I enter some valid value to combobox, press tab, shift+tab , 44
dropdown menu opens OK.
How to fix ?
How to use VCSE 2008 with .net framework source code to find the line in
System.Windows.Forms.DataGridViewComboBoxCell.ComboBox_DropDown()
which causes this error ?
Andrus.
System.NullReferenceException was unhandled
Message="Object reference not set to an instance of an object."
Source="System.Windows.Forms"
StackTrace:
at
System.Windows.Forms.DataGridViewComboBoxCell.ComboBox_DropDown(Object
sender, EventArgs e)
at System.EventHandler.Invoke(Object sender, EventArgs e)
at System.Windows.Forms.ComboBox.OnDropDown(EventArgs e)
at myApp.myComboBox.OnDropDown(EventArgs e) in myComboBox.cs:line 71
at System.Windows.Forms.ComboBox.WmReflectCommand(Message& m)
at System.Windows.Forms.ComboBox.WndProc(Message& m)
at
System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.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.WmCommand(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at
System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.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.ComboBox.DefChildWndProc(Message& m)
at System.Windows.Forms.ComboBox.ChildWndProc(Message& m)
at
System.Windows.Forms.ComboBox.ComboBoxChildNativeWindow.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.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32
dwComponentID, Int32 reason, Int32 pvLoopData)
at
System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32
reason, ApplicationContext context)
at
System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason,
ApplicationContext context)
at System.Windows.Forms.Application.Run(Form mainForm)
.....