Managed C++/CLI

Re: using unmanaged lib in managed class

1-Oct-09 3:34

i'll give it a try...but i'm new to c++ programming..i have only developed thing through application by now Smile | :)

so i have to skill a lot. Now i'll try to look at the stack frame to see if i can understand something

Richard MacCutchan1-Oct-09 5:21

Richard MacCutchan

1-Oct-09 5:21

carlo.andreoli wrote:
i'll give it a try...but i'm new to c++ programming

Maybe you should have started with a simpler project! Learning C++ is not the easiest task, even for programmers coming from C or Pascal background. You made it even harder by going for the managed C++/CLI form which adds a whole extra level of complexity. Buona fortuna!

cli::array<any^>^ Array

jashimu29-Sep-09 7:12

jashimu

29-Sep-09 7:12

Hello Everyone, I am struggling with a problem for two days and could not figure out what to do.

Here what I am trying to do.
I have cli<array> which is two dimentional. I get data in that array but is not in order. I want to copy that data in a temp array [same type] in order. I want change the location of the column and put it indore to the temp array.

example,original array A[0,0]
A[0,1]
A[0,2]
A[0,3]

I want to copy column in a different location of the new array
B[0,0]=A[0,2]
B[0,1]=A[0,3]
B[0,2]=A[0,0]
B[0,3]= A[0,0];

If anybody can please give me a hint would be very helpful.
if you did not understand the question please ask me I really need it soon.

Thanks in advance.

N a v a n e e t h29-Sep-09 17:58

29-Sep-09 17:58

What specific problem are you facing here?

Navaneeth

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jashimu30-Sep-09 4:32

jashimu

30-Sep-09 4:32

Hi Navaneeth, Sorry to answer you late but thanks for your kindness.

the question I have is I want to copy a two dimentional array but not just a carbon copy. I want to get what ever index I want and insert into a new array.
for example, array A has 10 index and I want to copy array A to Array B but not same order.array A's index 1,3,6,8 I want it to be array B's index 1,2,3,4.

how do I do this.

Sorry question may trivial but I need to know it since I am not a expert yet.

thanks

Jashim

Richard MacCutchan30-Sep-09 22:18

Richard MacCutchan

30-Sep-09 22:18

jashimu wrote:
I want to copy column in a different location of the new array
B[0,0]=A[0,2]
B[0,1]=A[0,3]
B[0,2]=A[0,0]
B[0,3]= A[0,0];

I think this is your only solution, since there appears to be no logical order to your input data.

problem extending datetimepicker

jashimu1-Oct-09 6:50

jashimu

1-Oct-09 6:50

I figure it out the same. I did manually everything.

thanks for your reply Richard.

jashim

carlo.andreoli27-Sep-09 21:50

27-Sep-09 21:50

googling around i found some extension to the default tiempicker to make backcolor suitable...what i have till now is:

namespace primoAlpha {

	using namespace System;
	using namespace System::Drawing;
	using namespace System::Windows::Forms;
	using namespace System::Security::Permissions;

	public ref class extendedDateTimePicker : DateTimePicker
	{
	private:		
		Color _BackColor;
	public:
		property Color BackColor  
		{
			virtual Color get() override {
				return _BackColor;
			}
			virtual void set(Color value) override	{
				_BackColor = value;
				Invalidate();
			}
		}

	protected:
		[SecurityPermission(SecurityAction::Demand, Flags=SecurityPermissionFlag::UnmanagedCode)]
		virtual void WndProc( Message% m ) override
		{	
			if ( m.Msg == (int) 0x0014 ) {	//WM_ERASEBKGND
				
				Graphics ^g = Graphics::FromHdc(m.WParam);
				g->FillRectangle(gcnew SolidBrush(_BackColor),
				ClientRectangle);
				g->ReleaseHdc();
				//g->Dispose();
				return;
				
			}
			WndProc(m);
		}
	};

}

the code compile with no error but when i run it gives me an
"An unhandled exception of type 'System.StackOverflowException' occurred in primoAlpha.exe"

any help is really apprecieted, i'm a noob in c++

Luc Pattyn28-Sep-09 0:30

28-Sep-09 0:30

Hi,

IMO your WndProc is calling itself instead of the base WndProc method. I don't know the correct C++/CLI syntax for it though.

Smile | :)

Luc Pattyn

Local announcement (Antwerp region): Lange Wapper? Neen!

carlo.andreoli28-Sep-09 1:52

28-Sep-09 1:52

the code from which i constrcuted the code tell to use

Form::WndProc(m);

but if try to use it it tell me "candidate function(s) not accessible"

cause Form::WndProc is a private code.

Luc Pattyn28-Sep-09 2:08

28-Sep-09 2:08

it works in C#:

public class extendedDateTimePicker : DateTimePicker {
    protected override void  WndProc(ref Message m) {
         base.WndProc(ref m);
    }
}

BTW: the message parameter takes a reference.

Smile | :)

Luc Pattyn

Local announcement (Antwerp region): Lange Wapper? Neen!

N a v a n e e t h28-Sep-09 2:33

28-Sep-09 2:33

Luc Pattyn wrote:
the message parameter takes a reference.

Do you have any idea why it is passed as reference?

Navaneeth

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Luc Pattyn28-Sep-09 2:41

28-Sep-09 2:41

the message is a struct you may want to modify and pass on.

Smile | :)

Luc Pattyn

Local announcement (Antwerp region): Lange Wapper? Neen!

N a v a n e e t h28-Sep-09 2:43

28-Sep-09 2:43

Ahh. That was simple. I was not aware that Message is a struct.

Thanks Thumbs Up | :thumbsup:

Navaneeth

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Luc Pattyn28-Sep-09 2:56

28-Sep-09 2:56

With the number of messages flying around in Windows, they'd better be structs.

Smile | :)

Luc Pattyn

Local announcement (Antwerp region): Lange Wapper? Neen!

N a v a n e e t h28-Sep-09 2:31

28-Sep-09 2:31

Correct syntax is BaseClassName::MethodName. So you write DateTimePicker::WndProc(m).

C++

public ref class extendedDateTimePicker : DateTimePicker
{
protected:
	[SecurityPermission(SecurityAction::Demand, Flags=SecurityPermissionFlag::UnmanagedCode)]
	virtual void WndProc( Message% m ) override
	{	
		if ( m.Msg == (int) 0x0014 ) {	//WM_ERASEBKGND
                     // your code				
		}
		DateTimePicker::WndProc(m);
	}
};

Navaneeth

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carlo.andreoli28-Sep-09 3:12

28-Sep-09 3:12

antd the winner is "N a v a n e e t h" ...thank you man...you pointed out the problem...still i'm wondering why i didn't get it by my self Laugh | :laugh:

N a v a n e e t h28-Sep-09 4:04

28-Sep-09 4:04

Winner should be Luc as he pointed out the problem. I am just a syntax provider. Smile | :)

Navaneeth

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modified on Monday, September 28, 2009 10:22 AM

carlo.andreoli28-Sep-09 20:37

Communicating with main GUI thread from worker thread

28-Sep-09 20:37

yes...but i know only c++ and base for me before today was an unknown identifier... now i know it's a pointer to the "base class" from which i derive mine Smile | :)

LetsMond15-Sep-09 1:25

LetsMond

15-Sep-09 1:25

I have a background worker thread which I run to analyse some data the results of which I want to dipslay in the GUI. My question is how do I inform the main GUI thread that the worker thread has finished (the data is ready) so that it can update the GUI. I do not want to pause the main GUI thread to wait for the worker thread.

The only method I know (used back before Managed C++/CLI) is to send a windows message from the worker thread. This is handled in the message loop of the main GUI thread and so the GUI can be updated. However this feels a bit clunky to me and can cause problems when a dialog is open and the windows message is handled in the dialog's message loop and not that of the main application.

Does anybody know of a better method?

Re: Communicating with main GUI thread from worker thread

N a v a n e e t h15-Sep-09 2:17

Re: Communicating with main GUI thread from worker thread

15-Sep-09 2:17

LetsMond wrote:
how do I inform the main GUI thread that the worker thread has finished (the data is ready) so that it can update the GUI

Once done, call a method that updates GUI thread. Only thing to take care is to use Invoke/BeginInvoke. Here is a sample code.

MethodInvoker^ method = gcnew MethodInvoker(this, &YourForm::UpdateUI);
this->BeginInvoke(method);

This sends a message to the main thread's message loop. You can update the controls inside the method UpdateUI.

MethodInvoker is delegate supplied with .NET framework. If you want to pass additional arguments to method, you may need to create your own delegates.

LetsMond wrote:
The only method I know (used back before Managed C++/CLI) is to send a windows message from the worker thread. This is handled in the message loop of the main GUI thread and so the GUI can be updated.

This is the correct method. Message sending is encapsulated inside Invoke or BeginInvoke methods. These methods calls win32 SendMessage and PostMessage.

Navaneeth

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LetsMond15-Sep-09 3:53

LetsMond

15-Sep-09 3:53

Thanks. This will do what I need.

Re: Communicating with main GUI thread from worker thread

N a v a n e e t h15-Sep-09 16:13

Re: Communicating with main GUI thread from worker thread

15-Sep-09 16:13

Good to hear that it helped.

If you are interested, another possible method to do cross thread communication is to use SynchronizationContext[^] class. This will do the marshaling and provide a neat way for cross-thread communication.

Here is a sample code.

C++

SynchronizationContext^ context = SynchronizationContext::Current;
Thread^ t = gcnew Thread(gcnew ParameterizedThreadStart(this, &YourForm::Execute));
t->Start(context);

void Execute(Object^ obj)
{
    SynchronizationContext^ context = dynamic_cast<SynchronizationContext^>(obj);
    context->Post(gcnew SendOrPostCallback(this, &YourForm::UpdateUI), "Sample text");
}

void UpdateUI(Object^ obj)
{
   // your UI update code
}

Navaneeth

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N a v a n e e t h15-Sep-09 2:25