Managed C++/CLI

Re: Convert Native Pointer to IntPtr

22-May-21 4:47

The documentation at Marshal.StringToHGlobalAnsi(String) Method (System.Runtime.InteropServices) | Microsoft Docs[^] says you can just free the native pointer.

Richard Andrew x6422-May-21 4:51

Richard Andrew x64

22-May-21 4:51

Thanks Richard, I was just about to delete this post because I just realized that I could do FreeHGlobal(IntPtr(pFullUrl)) as long as pFullUrl is a LONGLONG.

Thank you for your response.

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

Backgammon Game

basel3322-May-21 2:25

basel33

22-May-21 2:25

Backgammon Game (Classic Backgammon(known as Erkek Tavlası in Turkish) Programming using Files.
You will create and maintain 2 files, one for Backgammon table (name must be Table.dat)(figure 2), the second table
is for Dice history and play log

Kodu bilen var mı?

Re: Backgammon Game

Richard MacCutchan22-May-21 3:13

Serial Port BytesToRead always 0

22-May-21 3:13

basel33 wrote:
You will create and maintain

Yes, you will, not anyone else.

basel33 wrote:
Kodu bilen var mı?

Yok.

yehiga146721-May-21 0:16

yehiga1467

21-May-21 0:16

Hello everyone,

I made a class that will do some additional configuration to the serial port. (Mainly to handle received data).
My issue is that SerialPort_DataReceived() is successfully triggered when it received data from device, however the BytesToRead is always 0. What could the reason be? I am sure the device is sending data because when I haven't use this ConfigSerialPort, everything works fine.

ConfigSerialPort.h

#pragma once
using namespace System::Windows::Forms;

ref class ConfigSerialPort: public System::Windows::Forms::Control
{

	private: System::IO::Ports::SerialPort^ _serialPort;
	
	public:
		ConfigSerialPort(System::IO::Ports::SerialPort^ serialPort) {
			_serialPort = serialPort;
			
        //handle received data
			_serialPort->DataReceived += gcnew System::IO::Ports::SerialDataReceivedEventHandler(this, &ConfigSerialPort::SerialPort_DataReceived);
		
		}
		
	private: 	System::Void SerialPort_DataReceived(System::Object^ sender, System::IO::Ports::SerialDataReceivedEventArgs^ e)
    {
        unsigned int test = 0;

        test = _serialPort->BytesToRead; // BytesToRead is ALWAYS Zero
    }

}

MyForm.h

#pragma once

#include <stdlib.h>
#include <string.h>
#include <cstdint>
#include <stdio.h>
#include "ConfigSerialPort.h"



namespace SerialPortGUI {

	using namespace System;
	using namespace System::ComponentModel;
	using namespace System::Collections;
	using namespace System::Windows::Forms;
	using namespace System::Data;
	using namespace System::Drawing;

	using namespace System::IO;
	using namespace System::Runtime::Serialization::Formatters::Binary;






	/// <summary>
	/// Summary for MyForm
	/// </summary>
	public ref class MyForm : public System::Windows::Forms::Form
	{
		public:
			MyForm(void)
			{
				InitializeComponent();
				//
				//TODO: Add the constructor code here
				//
			}
			.
			.
			.
			
			
			void InitializeComponent(void)
			{
				.
				.
				.
				this->Load += gcnew System::EventHandler(this, &MyForm::MyForm_Load);
			   this->MyForm_SerialPort = (gcnew System::IO::Ports::SerialPort(this->components));
			   
				.
				.
				.

			}
		private: ConfigSerialPort^ test;
		private: System::Void MyForm_Load(System::Object^ sender, System::EventArgs^ e) {
		
		// initialize Serial port (already done via the designer)
		test = gcnew ConfigSerialPort(MyForm_SerialPort);
		
		}
	}
			
}

Richard MacCutchan21-May-21 0:59

21-May-21 0:59

What is the serial port connected to, and how can you tell there is data to be read?

cibec75455@frnla.com21-May-21 1:29

cibec75455@frnla.com

21-May-21 1:29

Hello, my other device is an Arduino that connects to PC as Com port 8. Every time I press a button on Arduino, it will transmit a text over serial to the PC. I have verified the received text using Termite software.

Richard MacCutchan21-May-21 1:38

21-May-21 1:38

It's impossible to guess why your receiver thinks there is no data to read, if it is being transmitted.

How to call System::Windows::Forms::Controls "invoke" method?

cibec75455@frnla.com21-May-21 1:47

cibec75455@frnla.com

21-May-21 1:47

The only think I could think of is inside

ConfigSerialPort.h

I should use gcnew for _serialPort

_serialPort = gcnew (System::IO::Ports::SerialPort);

, and then assign it the parameter

_serialPort = serialPort

Member 1515077819-May-21 19:48

Re: How to call System::Windows::Forms::Controls "invoke" method?

19-May-21 19:48

I made a class myGroupbox to use SerialPort, and I'm trying to update a textbox from the serial port data. But the invoke function couldn't be used, the error message is "myGroupbox has no member invoke"

here's my code

myGroupbox.h
#pragma once
using namespace System::Windows::Forms;
ref class myGroupbox
{
    private: System::IO::Ports::SerialPort^ _serialPort;
    
    public:
    myGroupbox( System::IO::Ports::SerialPort^ serialPort )
    {
    _serialPort=serialPort;
    
            _serialPort->DataReceived += gcnew System::IO::Ports::SerialDataReceivedEventHandler(this, &myGroupbox::SerialPort_DataReceived);
    }
    
  private: 	System::Void SerialPort_DataReceived(System::Object^ sender,System::IO::Ports::SerialDataReceivedEventArgs^ e)
    {
        uint16_t test = 0;

        test = _serialPort->BytesToRead;

        if (test == 3U) {



            this->Invoke(gcnew EventHandler(this, &myGroupbox::ProcessReceived)); // ERROR in this line, Invoke not found
        }
        else
        {
            _serialPort->DiscardInBuffer();
        }
    }

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

        //set textbox text

    }

}

Victor Nijegorodov19-May-21 20:28

Victor Nijegorodov

19-May-21 20:28

Member 15150778 wrote:
the invoke function couldn't be used, the error message is "myGroupbox has no member invoke"

Well, you hadn't defined any Invoke() method in your myGroupbox class. Therefore you got this error message.

Re: How to call System::Windows::Forms::Controls "invoke" method?

Member 1515077819-May-21 20:35

Re: How to call System::Windows::Forms::Controls "invoke" method?

19-May-21 20:35

Hello, I tried to copy my approach from the MyForm.cpp and it worked properly i.e. invoke wasn't define in MyForm.cpp but I could still call this invoke function since it's from System::Windows::Forms::Controls.

But in my own class myGroupBox, it couldn't do the same.

here's an snippet of MyForm.cpp that used the invoke and worked

using namespace System;
using namespace System::Windows::Forms;

[STAThreadAttribute]
void main(array<String^>^ args) {
	Application::EnableVisualStyles();
	Application::SetCompatibleTextRenderingDefault(false);
	myGUI ::MyForm form;
	Application::Run(% form);
}

namespace myGUI {


	System::Void MyForm::serialPort1_DataReceived(System::Object^ sender, System::IO::Ports::SerialDataReceivedEventArgs^ e) {
		if (serialPort1->IsOpen) {
			databufferA = serialPort1->ReadLine();
	this->Invoke(gcnew EventHandler(this, &MyForm::DisplayText));

		}
	}
}

modified 20-May-21 2:41am.

Richard MacCutchan19-May-21 21:09

Re: How to call System::Windows::Forms::Controls "invoke" method?

19-May-21 21:09

Yes, because you have still not declared an Invoke method in your class, and your class is not a child of System.Windows.Forms.Control.

Member 1515077819-May-21 21:20

What is a preferable approach to develop a common class that handles multiple identical groupbox?

19-May-21 21:20

Hello, thank you very much for your help! I am able to compile after following your suggestion. I will test if this method works and update if this is the final solution.

Thanks again!

myGroupbox.h
#pragma once
using namespace System::Windows::Forms;
ref class myGroupbox: public System::Windows::Forms::Control
{
    private: System::IO::Ports::SerialPort^ _serialPort;

.
.
.

Member 1515077818-May-21 0:41

How to convert array<System::Byte^>^ to array<unsigned char>^

18-May-21 0:41

Sorry if my question is unclear, but I shall explain a bit more in the following.

Suppose I am making a software to show ONLY 2 employee information (i.e. Bob and Tim), and my implementation method is to create 2 identical group box.
Each of this groupbox will have the same UI elements , textbox, checkbox, label and buttons.

In order to reduce duplicated codes , I want to create a common class for this groupbox.
Will this work?
Would there be memory leaks?
I did some google research and found something about using smart pointers instead of gcnew'ing a pointer, is it relevant to prevent memory leaks?

Thank you very much for reading, i appreciate any constructive help /example code to get this code properly working!

common_employee_groupbox.h

#pragma once
ref class common_employee_groupbox
{
private: System::Windows::Forms::CheckBox^ _cb_isAbsent = gcnew (System::Windows::Forms::CheckBox^ );  //IS this correct way to declare?
private: System::Windows::Forms::CheckBox^ _cb_isOverTime gcnew (System::Windows::Forms::CheckBox^ );  //IS this correct way to declare?

private: System::Windows::Forms::TextBox^ _tb_employeeName gcnew (System::Windows::Forms::TextBox^ );  //IS this correct way to declare?
private: System::Windows::Forms::TextBox^ _tb_employeeSalary gcnew (System::Windows::Forms::TextBox^ );  //IS this correct way to declare?

private: System::Windows::Forms::Button^ _btn_increaseSalary gcnew (System::Windows::Forms::Button^ );  //IS this correct way to declare?
private: System::Windows::Forms::Button^ _btn_decreaseSalary gcnew (System::Windows::Forms::Button^ );  //IS this correct way to declare?

public: 
    common_employee_groupbox(
    System::Windows::Forms::CheckBox^ cb_isAbsent,
    System::Windows::Forms::CheckBox^ cb_isOverTime,

    System::Windows::Forms::TextBox^ tb_employeeName,
    System::Windows::Forms::TextBox^ tb_employeeSalary,
    
    System::Windows::Forms::Button^ btn_increaseSalary,
    System::Windows::Forms::Button^ btn_decreaseSalary

) {
    _cb_isAbsent = cb_isAbsent;
    _cb_isOverTime= cb_isOverTime;
    _tb_employeeName= tb_employeeName;
    _tb_employeeSalary= tb_employeeSalary;
    _btn_increaseSalary= btn_increaseSalary;
    _btn_decreaseSalary= btn_decreaseSalary;


    _btn_increaseSalary->Click += gcnew System::EventHandler(this,&common_employee_groupbox::increaseSalary_Click); //IS this correct way to declare?
    
    _btn_decreaseSalary->Click += gcnew System::EventHandler(this,&common_employee_groupbox::decreaseSalary_Click); //IS this correct way to declare?
    
    
    	}
    
    private: System::Void increaseSalary_Click() {
    // perform increase salary
    
    tb_employeeSalary->Text = "updatedsalary xxxx"; 
    }
    
    private: System::Void decreaseSalary_Click() {
    // perform decrease salary
    
    tb_employeeSalary->Text = "updatedsalary xxxx"; 
    
    
    }


};

MyForm.h

#include "common_employee_groupbox.h"
namespace MyEmployeeGUI {

	using namespace System;
	using namespace System::ComponentModel;
	using namespace System::Collections;
	using namespace System::Windows::Forms;
	using namespace System::Data;
	using namespace System::Drawing;

	using namespace System::IO;
	using namespace System::Runtime::Serialization::Formatters::Binary;

    public ref class MyForm : public System::Windows::Forms::Form
	{
    private: System::Windows::Forms::CheckBox^ cb_isAbsent_Tim;
    private: System::Windows::Forms::CheckBox^ cb_isOverTime_Tim;
    private: System::Windows::Forms::TextBox^ tb_employeeName_Tim;
    private: System::Windows::Forms::TextBox^ tb_employeeSalary_Tim;
    private: System::Windows::Forms::Button^ btn_increaseSalary_Tim;
    private: System::Windows::Forms::Button^ btn_decreaseSalary_Tim;
    
    private: System::Windows::Forms::CheckBox^ cb_isAbsent_Bob;
    private: System::Windows::Forms::CheckBox^ cb_isOverTime_Bob;
    private: System::Windows::Forms::TextBox^ tb_employeeName_Bob;
    private: System::Windows::Forms::TextBox^ tb_employeeSalary_Bob;
    private: System::Windows::Forms::Button^ btn_increaseSalary_Bob;
    private: System::Windows::Forms::Button^ btn_decreaseSalary_Bob;
    	public:
    		MyForm(void)
    		{
    			InitializeComponent();
    			//
    			//TODO: Add the constructor code here
    			//
    		}


    
    .
    .
    .
    
    	System::Void MyForm::MyForm_Load(System::Object^ sender, System::EventArgs^ e) {
    
            common_employee_groupbox^ tim_groupbox = gcnew common_employee_groupbox(
                cb_isAbsent_Tim,
                cb_isOverTime_Tim,
                tb_employeeName_Tim,
                tb_employeeSalary_Tim,
                btn_increaseSalary_Tim,
                btn_decreaseSalary_Tim
            );  //IS this correct way to declare?
        
    
            common_employee_groupbox^ bob_groupbox = gcnew common_employee_groupbox(
                cb_isAbsent_Bob,
                cb_isOverTime_Bob,
                tb_employeeName_Bob,
                tb_employeeSalary_Bob,
                btn_increaseSalary_Bob,
                btn_decreaseSalary_Bob
            );  //IS this correct way to declare?
       
        }
    }
}

Update 1:

I have tried this code, and I'm having errors with this line (the bolded ampersand is highlighted as error) :

_btn_increaseSalary->Click += gcnew System::EventHandler(this,&common_employee_groupbox::increaseSalary_Click);

the error message:
invalid delegate initializer - function does not match the delegate type

How to fix this problem? Already tried googling, but the results aren't helpful

Update 2:

I have fixed the problem from update 1.
it turned out that I need to declare the increase/decrease salary function with the following arguments like below

private: System::Void increaseSalary_Click(System::Object^ sender, System::EventArgs^ e).

I have gotten the code to work as expected, however I'm still unsure if there will be any memory leaks.

Thanks all!

modified 19-May-21 22:45pm.

Member 1515077812-May-21 18:19

Re: How to convert array<System::Byte^>^ to array<unsigned char>^

12-May-21 18:19

I have an pointer to an array of System::Byte pointers, and im trying to use the SerialPort.Write function that only accepts

array<unsigned char>^

It is necessary that I used System::Byte pointers because the value of byte array needs to be update from time to time during runtime.

heres my sample code

System::Void MyForm::button1_Click(System::Object^ sender, System::EventArgs^ e)
{

    array<System::Byte^>^ myArray = gcnew array<System::Byte^>(10U);
    myArray[0] = (System::Byte) 0x01;
    myArray[1] = (System::Byte) 0x02;
    myArray[2] = (System::Byte) 0x03;
    myArray[3] = (System::Byte) 0x04;
    myArray[4] = (System::Byte) 0x05;
    myArray[5] = (System::Byte) 0x06;
    myArray[6] = (System::Byte) 0x07;
    myArray[7] = (System::Byte) 0x08;
    myArray[8] = (System::Byte) 0x09;
    myArray[9] = (System::Byte) 0x10;
    SerialPort1->Write(myArray,0,10U);/*ERROR,E0304  no instance of overloaded function "System::IO::Ports::SerialPort::Write" matches the argument list; argument types are: (cli::array<System::Byte ^, 1> ^, int, unsigned int)*/
        object type is: System::IO::Ports::SerialPort ^

}

modified 13-May-21 0:27am.

Richard MacCutchan12-May-21 21:05

Re: How to convert array<System::Byte^>^ to array<unsigned char>^

12-May-21 21:05

Why have you declared your array as Byte pointers, when it only contains single bytes in each element? And it is clear form SerialPort.Write Method (System.IO.Ports) | Microsoft Docs[^] that the method requires an array of Bytes.

Member 1515077817-May-21 0:06

How to implement a global variable if C++/CLI doesn't support it at all?

17-May-21 0:06

I fixed my problem already , Updated from array<system::byte^>^

to array<system::byte>^.

Member 1515077811-May-21 23:29

Re: How to implement a global variable if C++/CLI doesn't support it at all?

11-May-21 23:29

I'm trying to build a really simple class with member variables and member functions for learning.

I am trying to achieve the following code inside btn_User1_Click, however since user1 is not globally declared, it couldn't find the variable. At the same time, if I tried to declare this
myUser^ user1 = gcnew user1 (1002); outside the function , it gives an error syntax error missing ';' before '^'

myUser.h
#pragma once
ref class myUser
{

public: 
    myUser(unsigned int user_id) :id(user_id) {

...

	}


private:
    unsigned int id{ 0 };



public:

	System::Void increment_UserID() {

  id = id + 1;

	}
};

MyForm.cpp


namespace FACEDControllerGUI {

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

        myUser^ user1 = gcnew user1 (1002);
        myUser^ user2 = gcnew user1 (1005);

    }

	System::Void MyForm::btn_User1_Click(System::Object^ sender, System::EventArgs^ e) {
		user1->increment_UserID();
	}
	
	System::Void MyForm::btn_User2_Click(System::Object^ sender, System::EventArgs^ e) {
		user2->increment_UserID();
	}


} // end namespace

Richard MacCutchan11-May-21 23:47

Re: How to implement a global variable if C++/CLI doesn't support it at all?

11-May-21 23:47

You are creating user1 and user2 inside the MyForm_Load method, so as soon as that method ends the two variables disappear. You should create them in the class definition of MyForm so they are available to all methods of the class.

Member 1515077812-May-21 18:30

12-May-21 18:30

I have mentioned this following:
At the same time, if I tried to declare this
myUser^ user1 = gcnew user1 (1002); outside the function , it gives an error syntax error missing ';' before '^'

Fortunately, I have solved my problem. It is due to #include function of the class is placed in the .cpp file, instead of the .h file

cpp

likith adithya21-Feb-21 23:39

likith adithya

21-Feb-21 23:39

1.	What is friend function and friend class? Class "stu-info" stores all the details related to students like (name, reg, section , marks of 5 subjects). Class "show_details" will act like a friend of class "stu-info" and perform following operations: basic_details() and result(). These functions will work on the private data members of "stu-info".

Re: cpp

Richard MacCutchan21-Feb-21 23:40