instance does not exist in the current context - C# Discussion Boards

Re: C# and C++ class in dll

30-Apr-07 21:00

Its only an error if the value is a string. If it's a number at any point in the process, the 0s are meaningless, and therefore discarded.

You can use string.Format to format a string to have as many zeros as it needs to fit this format.

Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

C# and C++ class in dll

Levnsn30-Apr-07 19:57

Levnsn

30-Apr-07 19:57

Hi every one! I've create my own C++ class and push it to the dll. I need to get only one function from it. It fills many variables of this class. I need to get them, but i don know how. One of this var is vector<string> how can i get this data? I have read the article about calling functions from dll, but i can't get data from my var.
Thanks.

Christian Graus30-Apr-07 20:45

30-Apr-07 20:45

A vector is a C++ class, you'd need to push out an array ( which is what the vector is wrapping ) instead.

window forms

kalyan_241630-Apr-07 18:29

kalyan_2416

30-Apr-07 18:29

hi all
i have got two forms one up on the other..
now if i click on the form which is behind the form which is on top is going behind..
i dont want that to happen...
i want the form which is in front should take info. and then active the form behind....
please help me for the necessary..
thanks bye

Re: window forms

Kashif Iqbal Khan30-Apr-07 19:49

Kashif Iqbal Khan

30-Apr-07 19:49

I think you need to show a from on top. Considering form1 is the Form object that you want to keep on top of form2

use form1.TopMost = true before calling form1.Show() or form1.ShowDialog()

Re: window forms

Christian Graus30-Apr-07 20:58

instance does not exist in the current context

30-Apr-07 20:58

If form2 is a child of form1, set the owner of form2 to be form1. Then, form2 will always stay above, as achild window should.

Latheesan30-Apr-07 17:50

30-Apr-07 17:50

I'm create an instance called shtb like this:

public form1()
{
InitializeComponent();

SyntaxHighlightingTextBox shtb = new SyntaxHighlightingTextBox();
...
}

Later in the script, i tried to use the instance shtb like this:

static string strMyOriginalScript = "";
private void form1_Load(object sender, System.EventArgs e)
{
strMyOriginalScript = shtb.Text;
}

When ever i try to build the solution, i keep getting the error:

'Editing Area' does not exist in the current context

Where im i going wrong? Can anyone help me with atleast this?

Latheesan30-Apr-07 17:53

30-Apr-07 17:53

I tried editing like this also:

static string strMyOriginalScript = "";
private void form1_Load(object sender, System.EventArgs e)
{
SyntaxHighlightingTextBox shtb;
strMyOriginalScript = shtb.Text;
}

still didn't work... where im i going wrong?

andreshs130-Apr-07 19:51

andreshs1

30-Apr-07 19:51

the problem is with the object not with the string,
define the object outside the constructor, just below the definition of the class

public class form1
{

SyntaxHighlightingTextBox shtb = null;

..................
.............
...

and then in the constructor you initialize the object

public form1()
{
InitializeComponent();

shtb = new SyntaxHighlightingTextBox();
...

Andres

"Learn from the mistakes of others.
You can't live long enough to make them all yourself."

"Failure doesn't mean I'm a failure, It does mean I have not yet succeeded;
Failure doesn't mean that I should give up, It does mean that I should try harder;
Failure doesn't mean that I will never make it, It does mean that I need more practice".

Thank you for helping.

Christian Graus30-Apr-07 22:26

30-Apr-07 22:26

Latheesan wrote:
SyntaxHighlightingTextBox shtb = new SyntaxHighlightingTextBox();

If this is a control, you need to set it's location on the form and add it to the forms Controls collection. Otherwise, it's just a local variable that disappears as soon as it goes out of scope. Even if it was a member, if it's not in the Controls collection, it's not on the form

Latheesan1-May-07 5:43

1-May-07 5:43

Yes, it was a control that was provided from an external .dll

so, i added the dll into my project reference first and then, in the top of the form1.cs, i have this code:

using SyntaxHighlighting;

and iniside the form1_Load(); i have this code now:

Controls.Add(shtb);

Yet, i still get that error "The name 'shtb' does not exist in the current context"

Christian Graus1-May-07 10:40

1-May-07 10:40

The error that was pointed out to you is still the case. If you create it in your constructor, locally, then it doesn't exist anymore in your load event. You should call the constructor in your load event. Scratch that. You buy a book on VB.NET, read it, work through it, and start another project when you've learned some basics. If you don't understand variable scoping, you frankly should not be writing code, sorry.

Latheesan1-May-07 6:03

Writing to a network drive - FileIOPermission

1-May-07 6:03

Wow... nobody here knew the answer, after 3 hours of tedious research, i finally came to this solution:

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=523645&SiteID=1[^]

I hope this will helpe someone out here with the same problem as me.

andreshs130-Apr-07 17:09

andreshs1

30-Apr-07 17:09

Hi there

I need to be able to write logs to a network drive, but I cannot get the FileIOPermission to work,

I am using the code below
[CODE]

PermissionSet ps1 = new PermissionSet(PermissionState.None);
ps1.AddPermission(new FileIOPermission(FileIOPermissionAccess.Read | FileIOPermissionAccess.Write, m_LogFile));
ps1.Demand();

[/CODE]

but when I try to write to the file I get the following Error

[CODE]
Request for the permission of type System.Security.Permissions.FileIOPermission, mscorlib, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089 failed.
[\CODE]

What should I use instead????

Regards
Andres

Design Time Error, problems reading file

Patricker30-Apr-07 16:12

Patricker

30-Apr-07 16:12

I have a UserControl. When I instantiate it the UserControl reads in an image that it uses, it draws it underneath the cursor. If I programmatically add the UserControl to a form and then run the program it works perfect. However if I try to do this via design time support I get an error screen instead of a design time screen, the error is:

"One or more errors encountered while loading the designer. The errors are listed below. Some errors can be fixed by rebuilding your project, while others may require code changes."

The reason for the error is that it can't find my image file, because instead of looking for it in my programs folder it looks for it in the Visual Studio IDE Folder.

"Could not find file 'C:\Program Files\Microsoft Visual Studio 8\Common7\IDE\images\tileselect.png'. " Is the exact error I get.

My original idea was to just remove design time rendering of the control, since it works just fine when I run it, but I couldn't figure out how to make it so that a control is not rendered when you use it in design time. Though design-time support is preferred.

Any help on this would be great. I am actually using a combination XNA/Windows Forms but from what I can tell that should have no bearing on the issue.

Source Code At Problem:

tileSelect = Texture2D.FromFile(GraphicsDevice, "images/tileselect.png");

If I remove this line, and the line that draws the sprite, it will work fine in Design time, it even calls the On_Paint event and runs the XNA code to clear the screen, not shown. Is there maybe some way I could rewrite my path so that it would look in my programs directory... No idea, thats why I posted here Smile | :)

Thanks in advance.

--Peter

Re: Design Time Error, problems reading file

Luc Pattyn30-Apr-07 23:28

Luc Pattyn

30-Apr-07 23:28

Hi,

you can use Component.DesignMode to have another file path (or no file loading)
while in design mode...

Smile | :)

Luc Pattyn

[My Articles]

Re: Design Time Error, problems reading file

Patricker30-Apr-07 23:58

Patricker

30-Apr-07 23:58

Worked Great, thanks.

--Peter

Accessing a method in the Main Form from a user control.

CombatSheep30-Apr-07 15:39

CombatSheep

30-Apr-07 15:39

Hello.

I have a windows forms application (.NET 3.0)
where I have a user control ( a sort of spine) on a Form (called imaginatively enough MainForm).
In the spine I make a call to a WCF service (in a seperate thread). I need to be able to (from this seperate thread) to call a method (DisplayNotification) on the MainForm and pass it a parameter (or two).
I just can't seem to do this. I am however able (with delegates) to do this with methods/controls on the spine. But unfortunate not the MainForm.
Can someone give me a leg up on this?

Basically:

Spine(usercontrol on MainForm) ->starts thread(WCF service) ->needs to access DisplayNotification() on MainForm.

I tried using FindContol() and even .Parent but I am embarassed to say...
I don't know how to use it. I can get a list of controls that match the control I want. I get it in a the form of ArrayOfFormControls[]. It's just that I don't know how to invoke properties on the say ArrayOfFormControls[0].

Can you point me towards an example? Basically I would prefer to use a METHOD in the MainForm to do my dirty work, rather than use properties on the control itself.

Some have mentioned using reflection, I'm afraid I have no experience with using reflection. Can you point towards an example or tutorial. I have googled it, and come up short....

There has also been talk of passing a reference to the mainform in the constructor of my usercontrol. Any concrete examples?

Thanks!

----------------------------------------
Code is sexy. Go get some.

Re: Accessing a method in the Main Form from a user control.

Arun.Immanuel30-Apr-07 16:01

Arun.Immanuel

30-Apr-07 16:01

Of course U can do that with the help of delegates.

In the main form create a delegate that calls the function in the mainform.

Pass the delegate as a parameter to a public function in the subform(just after creating the usercontrol).

The public function should assign the argument to a local delegate.

So, whenever U wish to call the mainForm function, call the local delegate
after checking for null.

Regards,
Arun Kumar.A

Changing the connection string of a typed dataset programatically

Rocky#30-Apr-07 15:15

Rocky#

30-Apr-07 15:15

hi every one,
I am making a Windows application in C# 2.0 and I was trying to give the connection String dynamically to the dataset bcz it would contain sensitive information otherwise. That's bcz I'm using Sql Server Authentication to logon to the database.

@"Data Source=LEOPARD\ATECH;Initial Catalog=KPS;User ID =Rocky;

The password is yet to be given and as long as I dont give it this exception will not stop from comming. The dataset wizard asked the question of including the sensitive info (passwrd) in the connection string but I refused and it said that you'd have to add that programatically on ur own. So there's gotta be a way to do it somehow. Can any buddy plz tell me that?

thanks in advance,

Rocky

form's opacity

adel_soli30-Apr-07 14:35

adel_soli

30-Apr-07 14:35

hi all,
i need to make an application that use a changable form's opacity
that when i change the value of a NumericUpDown control
the value of the form's opacity change

and that what i trayed to do

private void numericUpDown1_ValueChanged_1(object sender, EventArgs e)<br />
        {<br />
            this.Opacity =Convert.ToDouble(numericUpDown1.Value);<br />
        }

but it didn'n work Cry | :((

the form's opicity didn't change
can i do what i need or that's not allowed in C#?
thanks in advance
and sorry for my English Blush | :O

Re: form's opacity

Christian Graus30-Apr-07 14:47

30-Apr-07 14:47

adel_soli wrote:
Convert.ToDouble

Here's your problem. The opacity is a value between 0.0 and 1.0. Your numeric up down control isn't showing doubles. Did you stop to think why it needed a double ?

this.Opacity = numericUpDown1.Value/100.0;

will work, assuming the range of the control is 0 - 100.

Re: form's opacity

adel_soli1-May-07 1:30

adel_soli

1-May-07 1:30

sorry christian

but it didn't work
it gives me the following error

Operator '/' cannot be applied to operands of type 'decimal' and 'double'

Re: form's opacity

Christian Graus1-May-07 1:49