Managed C++/CLI Discussion Boards

why do you care about any "other faster way"?
How long is/are the array(s) to be converted? How often are you going to convert it/them?

Why are you using int's through handles and gcnew?

Why don't you just say

C++

Int32 bytesToRead = 0;
Int32 counter = 0;

??

The difficult we do right away...
...the impossible takes slightly longer.

Hi,
i made a library in c++/cli and beside a c# program calling it. Everything works fine when i compile on any cpu or x64 on my pc (x64os/x64proc). But if i compile for x86, c# part works fine, but when i use the c++/cli part i get the error "could not load file or assembly .... incorrect format" . I use user32.lib in the c++/cli, is it possible the problem come from here ?

---- Edit
I think it's ok, i activated copy reference to output project but i'm not sure it was that.

modified 30-May-21 17:11pm.

When you get a message like that, one project is compiling for either 32 or 64 bit and the other project is compiling for the opposite.

If the target is "Any CPU", a project will compile so that if the code runs on a 64-bit machine, it'll run as a 64-bit process, and if on a 32-bit machine, as a 32-bit process.

To solve this, make sure both projects build as either x64 or x86. Which depends on your requirements, but both projects have to build targeting the same thing.

Asking questions is a skill
CodeProject Forum Guidelines
Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

how do you copy the bytes of a managed variable to another managed variable? memcpy doesn't work since my arguments are not the correct type for memcpy

#include "string.h" //Updated Solution
    float^ f = gcnew (float);
    unsigned int^ temp = gcnew(unsigned int);
	*temp = 0;
	*temp = _byte3;
	*temp = (*temp << 8U) + _byte2;
	*temp = (*temp << 8U) + _byte1;
	*temp = (*temp << 8U) + _byte0


//	memcpy(f, temp,4U); //error


//Updated solution : 

		pin_ptr<float> pinPtr_FloatVal = &(*f);


		pin_ptr<unsigned int> pinPtr_UintVal = &(*temp);


	memcpy_s(pinPtr_FloatVal , 4U, pinPtr_UintVal , 4U); //4U i.e. 4 bytes

modified 28-May-21 8:32am.

c++ cli - Memcpy of native array to managed array in C++ CLI - Stack Overflow

Hello, I am trying to memcpy two managed values. The link provided seem to be for unmanaged to managed?

Could you show an example how to achieve this? Thanks!

Are you banned by Google? Confused | :confused:

memcpy in managed c /cli - Google Search

modified 28-May-21 8:00am.

The link that Victor gave you shows how to get a pointer to a managed object in order to copy data into it. So all you need is two such pointers in order to copy managed to managed.

Thank you very much Richard for elaborating a bit on this! I have solved my problem !

//Assuming int is on 4 bytes
typedef union u
{
int i;
byte b[4];
} U;

U x;
x.b[0] = 0 // Put first byte here
x.b[1] = 0 // second byte here, etc.

// Then use x.i as an integer

// Keep in mind that on Intel CPUs, integer values are represented in memory in reverse order.
// This means that hex value 0x11223344 will be represented in memory as 0x44, 0x33, 0x22, 0x11
// This is called little-endian vs. big-endian representation.
// There can be CPUs that uses the other convention.

// Make a small test project and play around with some values etc.

Hello all, my code requires the Serial Port to be static. Each time I make changes to the UI, I have to manually set the Serial Port to static.

like this

private: System::IO::Ports::SerialPort^ mySerialPort;

to this

private: static System::IO::Ports::SerialPort^ mySerialPort;

Is there a way to automatically be static?

Add it to your class manually rather than in the designer.

Thanks I have been adding the static keyword manually. But do you know if there is a way to automatically do this?

I have never tried, but I would not expect so. If you drag a control onto a form in the designer then the designer adds it to the Form's properties. But there is nothing (at least in C# Forms) that I can see that allows you to modify it to be static.

Hello,

I am trying to display float/double/integer to a string with custom format in Label. But I couldn't find snprintf available in managed c++. How can I achieve this?

Did you try ToString method?

int count = 100; 
System::String^ s = count.ToString();

Hello, I have tried ToString(), but I could not format to the how many decimal places to display .

Then use ToString() with the format specifications. See the example: Converting Double To System::string^ - C And C++ | Dream.In.Code

I am trying to set the image of a button when my Serial Port receives data.

After I receive the data, I use an Invoke to call MyForm::ProcessReceived, then from the MyForm::ProcessReceived to setAppearance. My setAppearance function is called, however the image on button is still showing the default image.

How do I show the new image in button?

System::Void MyForm::SerialPort_DataReceived(System::Object^ sender, System::IO::Ports::SerialDataReceivedEventArgs^ e)
{
    uint16_t test = 0;

    test = mySerialPort->BytesToRead;


        this->Invoke(gcnew EventHandler(this, &MyForm::ProcessReceived));

}


    System::Void MyForm::ProcessReceived(System::Object^ sender, System::EventArgs^ e) {

    // my_ReceivedData is just a custom class to parse & store received data
    my_ReceivedData^ status = gcnew my_ReceivedData;


    mySerialPort->Read(status->bytes, 0, length);
    mySerialPort->DiscardInBuffer();

    setAppearance(status->bytes);

}


public: System::Void setAppearance(array<unsigned char>^ bytes) {
    btn_Start->ImageIndex = 3; // function is excecuted, but image is still not updated from it's default
}

Update (Problem solved):

It turned out that the buttons were disabled so the background images couldnt be updated. After enabling the buttons, everything worked accordingly!

modified 26-May-21 1:11am.

Caveat: I'm not a C++ programmer so any syntax below may be incorrect.

The objects, properties and method signatures look like Windows Forms in .Net. If so, try ...

public: System::Void setAppearance(array<unsigned char>^ bytes) {
    btn_Start->ImageIndex = 3; // function is excecuted, but image is still not updated from it's default
    btn_Start->Refresh();
}

Hello, I seen that this Refresh() should force the button to redraw itself, and I tested but it still didn't work. I then guessed that the button was disabled and I was right, because the button is disabled it couldn't show the new background image.

Thanks for your help!

Did you try enabling, refreshing, then disabling so that the refresh happens whilst it is enabled but the chances of someone clicking it in the brief time it is enabled is slim? If you wanted to eliminate its clickablity whilst it is briefly disabled, you could change the click action to do nothing before enabling it and then restoring the normal click action after disabling it.

Not tried any of this myself, so I am just guessing but it is worth a go. It may be that the disabled visual element overrides the selected background image.

Hello jsc42, yes I have done this part to prevent the user from ever mistakenly clicking the button Smile | :)

. Thanks for the suggestion!

I am trying to call a function defined in the parent class via the object. But I am getting the error a pointer to member is not valid for a managed class. How can I achieve what I wanted? My expected output is to display the text "Called from child"

MyChild.h
ref class MyChild
{

       System:Void(*my_func_ptr)(int, char*);
       typedef System:Void(*MyFuncPtrType)(int, char*);
       MyFuncPtrType my_func_ptr;


	public: MyChild ( System:Void(*some_func)(int, char*)){

		my_func_ptr = some_func;
	}

	public: System::Void  Child_ButtonClicked(System::Object^ sender, System::EventArgs^ e){
		my_func_ptr();
	}

}



MyForm.h

#include "MyChild.h"

public ref class MyForm : public System::Windows::Forms::Form
{
.
.
.
	private: static System:Void test(int, char*) { //Update
		MessageBox::Show("Called from child");
	}


	private: System::Void MyForm::MyForm_Load(System::Object^ sender, System::EventArgs^ e) {
		MyChild^ child= gcnew MyChild( MyForm::test); //type incompatible error in this line
		child -> test(1,"random");
	}


}

Update 2, Previous problem for //type incompatible error in this line is solved using the following way below.

MyChild.h
ref class MyChild
{
	   
	   
	private:     System::Void(*my_func_ptr)(int, char*);

	public:	System::Void doFunction(int A, char* B) {
           (*my_func_ptr)(A,B);
       }


	public: MyChild ( System::Void(*func)(int A, char* B)){

		my_func_ptr = func;
	}

	public: System::Void  Child_ButtonClicked(System::Object^ sender, System::EventArgs^ e){
		doFunction(1,"random");  //the arguments here are not used in later program, it is just for testing a function ptr with arguments
	}

}



MyForm.h

#include "MyChild.h"

public ref class MyForm : public System::Windows::Forms::Form
{
.
.
.

	   typedef System::Void (*callback_function)(int, char*); 
	   
	   
	private: static System:Void test(int, char*) {
		MessageBox::Show("Called from child");
	}


	private: System::Void MyForm::MyForm_Load(System::Object^ sender, System::EventArgs^ e) {
	
	
	callback_function disc;

	disc = (callback_function)(MyGUI::MyForm::test);
	
		MyChild^ child= gcnew MyChild( disc);
		child -> doFunction(1,"random");
	}


}

For now, everything is solved but I am still unsure to the reason for incompatibility for argument and parameter having same type. I will do more trails and see if this is a stable way of implementation. Thanks for your help Richard Andrew x64 !

modified 25-May-21 0:07am.