C # control the printer through LPT1 Port

// C # control the printer (directly send the printer command to the printer)

// A printer control class, which is very useful. It uses windows api to control the lpt port. The method for controlling the bar code printer is as follows: Write the printer command to a file and then use it.

// Code:

Using System;

Using System. Collections. Generic;

Using System. Text;

Using System. Runtime. InteropServices;

 

Namespace LPTControls

{

Public class LPTControls

{

[StructLayout (LayoutKind. Sequential)]

Private struct OVERLAPPED

{

Int Internal;

Int InternalHigh;

Int Offset;

Int OffSetHigh;

Int hEvent;

}

[DllImport ("kernel32.dll")]

Private static extern int CreateFile (string lpFileName, uint dwDesiredAccess, int dw1_mode, int lpSecurityAttributes, int dwCreationDisposition, int dwFlagsAndAttributes, int hTemplateFile );

 

[DllImport ("kernel32.dll")]

Private static extern bool WriteFile (int hFile, byte [] lpBuffer, int nNumberOfBytesToWriter, out int lpNumberOfBytesWriten, out OVERLAPPED lpOverLapped );

 

[DllImport ("kernel32.dll")]

Private static extern bool CloseHandle (int hObject );

 

Private int iHandle;

 

// Open the LPT Port

Public bool Open ()

{

IHandle = CreateFile ("lpt1", 0x40000000, 0, 0, 3, 0, 0 );

If (iHandle! =-1)

{

Return true;

}

Else

{

Return false;

}

}

// Print function. The parameter is the printer command or other text!

Public bool Write (string MyString)

{

If (iHandle! = 1)

{

Int I;

OVERLAPPED x;

Byte [] mybyte = System. Text. Encoding. Default. GetBytes (MyString );

Return WriteFile (iHandle, mybyte, mybyte. Length, out I, out x );

}

Else

{

Throw new Exception ("port not opened ~! ");

}

}

// Close the print Port

Public bool Close ()

{

Return CloseHandle (iHandle );

}

}

}

 

//************************************** *************************

// Usage

Private void button#click (object sender, EventArgs e)

{

LPTControls. LPTControls lpt = new LPTControls. LPTControls ();

String mycommanglines = System. IO. File. ReadAllText ("print.txt"); // the command of the bar code machine is written in print.txt.

Lpt. Open ();

Lpt. Write (mycommanglines );

Lpt. Close ();

 

}