MyDocument Special Folder - C# Discussion Boards

Suggestions for debugging TreeView problem

stevoe7211-Aug-05 16:32

11-Aug-05 16:32

Hi,

I am getting the following NullReferenceException, erratically, from the System.Windows.Forms.TreeView component. As the stack trace shows, none of my code is *directly* involved in the exception. The exception seems to occur in response to an event that occurs after I perform some action on the TreeView...however, I cannot reliably reproduce the error, so I cannot determine which action preceeds the error.

Does any one have have any suggestions of approaches I can use to narrow down the cause of this error?

Thanks,
Steve.

Exception type: System.NullReferenceException Object reference not set to an instance of an object. 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.WmDestroy(Message& m) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.TreeView.WndProc(Message& m) at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Re: Suggestions for debugging TreeView problem

Susan Hernandez31-Aug-05 13:50

Susan Hernandez

31-Aug-05 13:50

stevoe72 wrote:
I am getting the following NullReferenceException, erratically, from the System.Windows.Forms.TreeView component. As the stack trace shows, none of my code is *directly* involved in the exception.

Did you ever get an answer to this question you posted on CodeProject? I am having similar problems, and don't know where the error is coming from. If you figured out where to look, I'd appreciate if you'd let me know. In my application, my users are seeing this error but I can't reproduce it.

Error Messages:<br />
Object reference not set to an instance of an object.<br />
	  Inner Stack Trace: <br />
	   at System.Windows.Forms.UnsafeNativeMethods.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)<br />
   at System.Windows.Forms.NativeWindow.DefWndProc(Message& m)<br />
   at System.Windows.Forms.Control.DefWndProc(Message& m)<br />
   at System.Windows.Forms.Control.WmUpdateUIState(Message& m)<br />
   at System.Windows.Forms.Control.WndProc(Message& m)<br />
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)<br />
   at System.Windows.Forms.ContainerControl.WndProc(Message& m)<br />
   at System.Windows.Forms.ParkingWindow.WndProc(Message& m)<br />
   at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)<br />
   at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)<br />
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Thanks for any help.
Sue

Re: Suggestions for debugging TreeView problem

stevoe7231-Aug-05 14:08

stevoe72

31-Aug-05 14:08

I'm afraid that I did not have any luck establishing the cause of this error, Susan...though we do *appear* to have stopped the error occurring (for the time being).

We started to suspect that the problem was somehow related to a panel, on my form, which was initially not visible when the form was displayed. My form had two "modes" of display. When the user switched mode, I would make the panel (and it's child controls) to be visible. When they switched modes again, the panel would be made invisible. From reading articles like the following, we began to suspect that there may be problems related to having a control that was initially non-visible:

http://www.dotnet247.com/247reference/msgs/57/285567.aspx[^]

http://www.tech-archive.net/Archive/DotNet/microsoft.public.dotnet.framework.windowsforms/2005-01/1163.html[^]

In the end, I split my form into 2 forms (one for each mode). I was able to remove the dynamic-nature of each form. All controls are visible when the form is first displayed. And the error seems to have stopped happening.

To me, it looks like the real error is occuring down in non-managed code. I don't know how to extract any further details from an error that occurs at such a level.

Hope some of this info is helpful to you. Sorry that I cannot provide a more definitive answer.

Cheers,
Stephen.

Re: Suggestions for debugging TreeView problem

Susan Hernandez31-Aug-05 14:14

Susan Hernandez

31-Aug-05 14:14

Actually, that may be the answer. We have several forms where we have initially non-visible panels with more controls in them. For instance if a user tries to type in a new address which is wrong, a panel becomes visible with a drop-down list of possible city/states.

Thanks very much for the links. I will look in to this, and play a little with visible/non-visible.

Smile | :)

Susan

apply control panel settings

Pyro Joe11-Aug-05 15:05

Pyro Joe

11-Aug-05 15:05

hi, I simply want to change the registry value "swapmousebuttons", I can do this. however I want to apply this setting without rebooting or logging off, much like the windows control panel does. how is this done? thanks for your help.
Stephen

Re: apply control panel settings

Mohamad Al Husseiny11-Aug-05 15:22

Mohamad Al Husseiny

11-Aug-05 15:22

You can use SwapMouseButton Api function

[DllImport("user32.dll")]
static extern bool SwapMouseButton(bool fSwap);

and somewhere write code like that

private void button3_Click(object sender, System.EventArgs e)
{
SwapMouseButton(true);
}

To set it back pass false value

SwapMouseButton Function[^]
MCAD

Re: apply control panel settings

Pyro Joe11-Aug-05 15:46

Pyro Joe

11-Aug-05 15:46

thanks a ton! it works perfectly.

MyDocument Special Folder

monrobot1311-Aug-05 14:21

monrobot13

11-Aug-05 14:21

I'm trying to find the path to the My Documents folder using the Environment.SpecialFolder enum, Path.GetFullPath (Environment.SpecialFolder.MyDocuments.ToString ()); but all that it's retuning to me is the full path to my executeable with "Personal" appended to the end. How do you use this enum to actually find the "My Documents" folder?

Thanks for the help.

- Aaron

Re: MyDocument Special Folder

Christian Graus11-Aug-05 14:33

Christian Graus

11-Aug-05 14:33

Environment.GetFolderPath( Environment.SpecialFolder.whatever)

Christian Graus - Microsoft MVP - C++

Re: MyDocument Special Folder

Mohamad Al Husseiny11-Aug-05 14:44

Mohamad Al Husseiny

11-Aug-05 14:44

monrobot13 wrote:
(Environment.SpecialFolder.MyDocuments.ToString ());

where did you get MyDocuments.ToString();
you need to write somthing like that

MessageBox.Show(Environment.GetFolderPath(Environment.SpecialFolder.Personal));

MCAD

Re: MyDocument Special Folder

monrobot1311-Aug-05 15:13

monrobot13

11-Aug-05 15:13

Thanks for the help.

- Aaron

Strage problem on AfterLabelEdit event of treeview

Dan Shi11-Aug-05 14:00

Dan Shi

11-Aug-05 14:00

hi, I was working on a treeview, and tried to handle the AfterLabelEdit event. Basically, what I want to do is, user need to change the text of a treenode once it's created. If the user doesnt change the text, a warning message is popup and the treenode get the focuse after user response to the warning message. My problem is, the warning message always popup twice!

Following is some of the code to handle AfterLabelEdit event,

private void tvInterface_AfterLabelEdit(object sender, System.Windows.Forms.NodeLabelEditEventArgs e)
{
if(e.Label != null)
{
//...
}
else
{
e.CancelEdit = true;
MessageBox.Show("Enter sth");
e.Node.BeginEdit();
}
}

Please help thanks!

Re: Strage problem on AfterLabelEdit event of treeview

Mohamad Al Husseiny11-Aug-05 15:23

Mohamad Al Husseiny

11-Aug-05 15:23

I tried your code but i got one message!

MCAD

Re: Strage problem on AfterLabelEdit event of treeview

Dan Shi12-Aug-05 13:43

Dan Shi

12-Aug-05 13:43

Thanks for trying. I also tried the code in the simplest case, one form with a treeview and a textbox.

The interesting thing is, when i click the textbox to trig the AfterLabelEdit event without making any change on the node label, the message box only pop up once. However, if i click somewhere else inside the treeview to trig the event, the message always pops up twice.

Really strange, I have no idea on how to block the second message box.

makefile and resources

dirkhelmet11-Aug-05 13:52

dirkhelmet

11-Aug-05 13:52

we use makefiles to build a very large application, and we are just starting with C# - we will need to use makefiles here too for the foreseable future.

I am having problems with ImageList added to a form. Inside DevStudio 2003, I add an imagelist with a few images, use some of the images in a toolbar and then save the form. When I build this simple app inside DevStudio, it runs fine.

I try to build this from the command line but when I do, it crashes on the following line:
this.imageList1.ImageStream = ((System.Windows.Forms.ImageListStreamer)(resources.GetObject("imageList1.ImageStream")));

Here's what the command line to build the app looks like:
csc /out:mytest.exe /t:winexe /nologo /debug+ /debug:full /res:Form1.resx AssemblyInfo.cs Form1.cs

Any ideas why it crashes when accessing the imagestream from the resources?
Thanks
Rich

remove the xxx's from the email address if you wish to write me directly.

again way to use flash inside c# application

malak nour11-Aug-05 13:43

malak nour

11-Aug-05 13:43

i need to use a flash design in my interface in aprogram wrote by c#
and i don't know way to do that
also how can i make animation in c#

Re: again way to use flash inside c# application

Mohamad Al Husseiny11-Aug-05 14:09

Mohamad Al Husseiny

11-Aug-05 14:09

Macromedia have flash player activex control you can use
it in .net application for more info look at
http://www.csharphelp.com/archives/archive81.html[^]
http://www.mix-fx.com/tutorials/insertvb6.html[^]

MCAD

Re: again way to use flash inside c# application

Mohamad Al Husseiny11-Aug-05 14:13

Mohamad Al Husseiny

11-Aug-05 14:13

malaky wrote:
how can i make animation in c#
you can use GDI+ to make animation
for example
http://www.c-sharpcorner.com/graphics/AnimationControl.asp[^]
http://www.dotnet247.com/247reference/msgs/3/19060.aspx[^]

MCAD

Axis

Anonymous11-Aug-05 13:41

Anonymous

11-Aug-05 13:41

I want to label tick marks along XYgraph axes. The code fragment below will draw the tick marks along the x-axis. It will also draw the labels (i.e. -8.0 -7.0, -6.0 etc...) but I can't seem to get the tick marks and the numbers to line up. One problem is that when the labels float value is >= 0.0, the minus sign disappears and skews the label from the tick mark...
//Here is the code fragment
void DrawGraphXandYTicks(Graphics g)
{
Pen tickPen = new Pen(new SolidBrush(Color.BlueViolet), 1);
//Draw x-axis ticks.
float f = -8.0f;
PointF xtickPoint = new PointF(xIndent, yIndent + graphRect.Height/2);
Font labelFont = new Font("Courier",6);
SolidBrush labelBrush = new SolidBrush(Color.BlueViolet);
StringFormat strFmt = new StringFormat();
for(float fx = xtickPoint.X; fx <= graphRect.Width; fx += xtickPoint.X)
{
g.DrawLine(tickPen, fx, xtickPoint.Y - 2, fx, xtickPoint.Y + 2);
g.DrawString(f.ToString("f1"), labelFont, labelBrush, fx + 14, xtickPoint.Y + 4, strFmt);
f++;

}
Please Advise and thanks in advance

Re: Axis

Christian Graus11-Aug-05 14:34

Christian Graus

11-Aug-05 14:34

Use Graphics.MeasureString to find out how big your string will be, and then divide this in half to make the text centre on the tick mark.

Christian Graus - Microsoft MVP - C++

Remoting question

machocr11-Aug-05 13:18

machocr

11-Aug-05 13:18

Hi, Im trying to make an aplication to no notity clients by remoting from one server.
I has this exception:
Type: SerializationException
Source: Because of security restrictions, the type System.Runtime.Remoting.ObjRef cannot be accessed.
Description: System.Runtime.Serialization.FormatterServices --> System.Object GetSafeUninitializedObject(System.Type)
What do I need in security? Confused | :confused:

How can I solvethis problem? D'Oh! | :doh:

I you need more information, jas say me.
Thank you!

La realidad no es más que impulsos eléctricos del cerebro - Morpheus

Re: Remoting question

Mohamad Al Husseiny11-Aug-05 13:32

Mohamad Al Husseiny

11-Aug-05 13:32

is this code written in previous version of .net framework 1

MCAD

Re: Remoting question

machocr11-Aug-05 13:43

machocr

11-Aug-05 13:43

Sorry, I forgets to say that he is in c# 2005
This would be the problem?

La realidad no es más que impulsos eléctricos del cerebro - Morpheus

Re: Remoting question

Mohamad Al Husseiny11-Aug-05 14:01

Mohamad Al Husseiny

11-Aug-05 14:01

problem like this appear when move code from .net framework 1 to 1.1 according to security setting
so may be this the case in .Net Framework 2
so check the documentaions
To see how the problem with solved in previous version
look at
http://www.gotdotnet.com/team/changeinfo/Backwards1.0to1.1/default.aspx#00000153[^]
http://www.thinktecture.com/Resources/RemotingFAQ/Changes2003.html[^]
http://weblogs.asp.net/jan/archive/2003/06/01/8106.aspx[^]

MCAD

Re: Remoting question

machocr12-Aug-05 6:09

machocr

12-Aug-05 6:09

Thank you so much! Cool | :cool:

I will read about.

La realidad no es más que impulsos eléctricos del cerebro - Morpheus

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