[elpap]

Hello
I'm a beginner in Visual C++ and I'm trying to established a serial communication.I am using VS 2010 and windows forms application to create my program.
I've made a devise that measures distance and sending the value to the PC.The Value of the measurement is changing continuously. So I need from my program to read the serial port continuously.
As you can see I'm using the ReadByte() method to read from the port and there is a loop to read from the port while the port is opened. I'm using ReadByte because the device sending to the PC 1 byte each time in hex.
But when I'm running the program and try to read from the port the following message shown:
-An unhandled exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll
-Additional information: Cross-thread operation not valid: Control 'textBox1' accessed from a thread other -than the thread it was created on.
It seems to be an error in the ReadData event. What I am doing wrong?
Thanks in advance.

private: System::Void ConnectBtn_Click(System::Object^  sender, System::EventArgs^  e) 
			 {
				 if  (!serialPort1->IsOpen)
				 {
					serialPort1->Open();
					serialPort1->DtrEnable=true;
					serialPort1->RtsEnable=true;
					ComStatusLabel->Text="Status:CONNECTED";
				 }
				 else
				 {
					 ComStatusLabel->Text="Status:DISCONNECTED";
				 }
				 try
				 {	
					serialPort1->ReadByte();
				 }
				 catch(TimeoutException^)
				 {
					 MessageBox::Show(" Σφάλμα Σύνδεσης ");
					serialPort1->Close();
					PortList->Enabled=true;	
					serialPort1->DtrEnable=false;
					serialPort1->RtsEnable=false;
					ComStatusLabel->Text="Status:DISCONNECTED";
				 }
			 }
	private: System::Void DisconnectBtn_Click(System::Object^  sender, System::EventArgs^  e) 
		 	{
			 	serialPort1->Close();
				serialPort1->DtrEnable=false;
				serialPort1->RtsEnable=false;
				PortList->Enabled=true;	
				ComStatusLabel->Text="Status:DISCONNECTED";
		 	}
	private: System::Void PortList_SelectedIndexChanged(System::Object^  sender, System::EventArgs^  e) 
			{
				//setting the Port name to read from the port we want to.
				String^ comname;
				comname=Convert::ToString(PortList->Text);
				serialPort1->PortName=(comname);
				PortList->Enabled=false;
		 	}
	private: System::Void FindPort_Click(System::Object^  sender, System::EventArgs^  e) 
		 	{
				PortList->Items->Clear();// Cleaning the existing List.
				//Creating the new list.
				array<String^>^ serialPorts = nullptr;//variable for storage the serial port names.
    			try
    			{
        			serialPorts = SerialPort::GetPortNames();// Get a list of serial port names.	
    			}
    			catch (Win32Exception^)
    			{
        			MessageBox::Show("Δεν βρέθηκαν θύρες");//message in case of errror.
    			}
				for each(String^ port in serialPorts)
				{
    				PortList->Items->Add(port );//store the port names to the ComboBox PortList.
				}
		 	}		 	
	private: System::Void DataRead(System::Object^  sender, System::IO::Ports::SerialDataReceivedEventArgs^  e) 
			{
				Byte data;
				do
				{
					textBox1->Text="";
					data=serialPort1->ReadByte();
					textBox1->Text=":"+data;
					serialPort1->DiscardInBuffer();
				}while(serialPort1->IsOpen);

		   	}

[JackOfAllTrades]

C# Tutorial on Cross-thread Commuication here at D.I.C.
MSDN Doc for Control.InvokeRequired