| Description |
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The AssignPrn procedure assigns the printer to a FileHandle. This means that subsequent text writing to this file gets rerouted to the printer. This provides a simpl and easy way of dumping out text to a printer.
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| Notes |
Warning : The AssignPrn mechanism is useful for simple programs, but lacks any control over printing for a real application.
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| Related commands |
| AssignFile |
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Assigns a file handle to a binary or text file |
| CloseFile |
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Closes an open file |
| ReWrite |
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Open a text or binary file for write access |
| Write |
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Write data to a binary or text file |
| WriteLn |
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Write a complete line of data to a text file |
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| Example code : Print a few words to the printer |
// Full Unit code.
// -----------------------------------------------------------
// You must store this code in a unit called Unit1 with a form
// called Form1 that has an OnCreate event called FormCreate.
unit Unit1;
interface
uses
Printers, // Unit containing the AssignPrn command
Forms, Dialogs;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm} // Include form definitions
procedure TForm1.FormCreate(Sender: TObject);
var
myFile : TextFile;
printDialog : TPrintDialog;
begin
// Create a printer selection dialog
printDialog := TPrintDialog.Create(Form1);
// If the user has selected a printer (or default), then print!
if printDialog.Execute then
begin
// Try to open a printer file
AssignPrn(myFile);
// Now prepare to write to the printer
ReWrite(myFile);
// Write a couple of well known words to this file -
// they will be printed instead
WriteLn(myFile, 'Hello');
WriteLn(myFile, 'World');
// Close the file
CloseFile(myFile);
end;
end;
end.
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| Hide full unit code |
After the user selects a printer, the following text is printed in a small font at the top left of the page:
Hello
World
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