FernandoPaiva FernandoPaiva - 1 year ago 286
C# Question

How to print a text file on thermal printer using PrintDocument?

I'm creating an application using C# with Winforms and now I need to print the receipt of sale on a thermal printer. To do this I'm creating a text file and reading it to print using the

but I cannot do this because I don't know how to configure paper size, align text center on the paper, and others configurations. When I do print the text file is printed, but all messy, and after the end print the paper isn't stopping.

How could I do this ?


private PrintDocument printDocument = new PrintDocument();
private static String RECEIPT = Environment.CurrentDirectory + @"\comprovantes\comprovante.txt";
private String stringToPrint = "";

private void button1_Click(object sender, EventArgs e) {

private void generateReceipt() {
FileStream fs = new FileStream(COMPROVANTE, FileMode.Create);
StreamWriter writer = new StreamWriter(fs);
writer.WriteLine(" NOME DA EMPRESA AQUI ");

private void printReceipt() {
FileStream fs = new FileStream(COMPROVANTE, FileMode.Open);
StreamReader sr = new StreamReader(fs);
stringToPrint = sr.ReadToEnd();
printDocument.PrinterSettings.PrinterName = DefaultPrinter.GetDefaultPrinterName();
printDocument.PrintPage += new PrintPageEventHandler(printPage);

private void printPage(object sender, PrintPageEventArgs e) {
int charactersOnPage = 0;
int linesPerPage = 0;
Graphics graphics = e.Graphics;

// Sets the value of charactersOnPage to the number of characters
// of stringToPrint that will fit within the bounds of the page.
graphics.MeasureString(stringToPrint, this.Font,
e.MarginBounds.Size, StringFormat.GenericTypographic,
out charactersOnPage, out linesPerPage);

// Draws the string within the bounds of the page
graphics.DrawString(stringToPrint, this.Font, Brushes.Black,
e.MarginBounds, StringFormat.GenericTypographic);

// Remove the portion of the string that has been printed.
stringToPrint = stringToPrint.Substring(charactersOnPage);

// Check to see if more pages are to be printed.
e.HasMorePages = (stringToPrint.Length > 0);

I'm trying create this model of receipt.

enter image description here

Using RDLC, but it is very slow to start print. I'm follow this example

//works but slow
private void Run() {
LocalReport report = new LocalReport();
report.ReportPath = @"..\..\reports\ReciboDeVenda.rdlc";

private void Export(LocalReport report) {
string deviceInfo =
Warning[] warnings;
m_streams = new List<Stream>();
report.Render("Image", deviceInfo, CreateStream,
out warnings);
foreach (Stream stream in m_streams)
stream.Position = 0;

private Stream CreateStream(string name, string fileNameExtension,
Encoding encoding, string mimeType, bool willSeek) {
Stream stream = new MemoryStream();
return stream;

private void Print() {
if (m_streams == null || m_streams.Count == 0)
throw new Exception("Error: no stream to print.");
PrintDocument printDoc = new PrintDocument();
printDoc.PrinterSettings.PrinterName = DefaultPrinter.GetDefaultPrinterName();
if (!printDoc.PrinterSettings.IsValid) {
throw new Exception("Error: cannot find the default printer.");
}else {
printDoc.PrintPage += new PrintPageEventHandler(PrintPage);
m_currentPageIndex = 0;

private void PrintPage(object sender, PrintPageEventArgs ev) {
Metafile pageImage = new Metafile(m_streams[m_currentPageIndex]);

// Adjust rectangular area with printer margins.
Rectangle adjustedRect = new Rectangle(
ev.PageBounds.Left - (int)ev.PageSettings.HardMarginX,
ev.PageBounds.Top - (int)ev.PageSettings.HardMarginY,

// Draw a white background for the report
ev.Graphics.FillRectangle(Brushes.White, adjustedRect);

// Draw the report content
ev.Graphics.DrawImage(pageImage, adjustedRect);

// Prepare for the next page. Make sure we haven't hit the end.
ev.HasMorePages = (m_currentPageIndex < m_streams.Count);

Answer Source

If you send a plain string to your printPage(object sender, PrintEventArgs e) method, it will just print plain text in all the same font which looks 'messy' (as you named it) If you want it to be printed well formatted with different fonts (bold, regular), you have to do it all manually:

List<string> itemList = new List<string>()
    "201", //fill from somewhere in your code

private void printPage( object sender, PrintPageEventArgs e )
    Graphics graphics = e.Graphics;

    Font regular = new Font( FontFamily.GenericSansSerif, 10.0f, FontStyle.Regular );
    Font bold = new Font( FontFamily.GenericSansSerif, 10.0f, FontStyle.Bold );

    //print header
    graphics.DrawString( "FERREIRA MATERIALS PARA CONSTRUCAO LTDA", bold, Brushes.Black, 20, 10 );
    graphics.DrawString( "EST ENGENHEIRO MARCILAC, 116, SAO PAOLO - SP", regular, Brushes.Black, 30, 30 );
    graphics.DrawString( "Telefone: (11)5921-3826", regular, Brushes.Black, 110, 50 );
    graphics.DrawLine( Pens.Black, 80, 70, 320, 70 );
    graphics.DrawString( "CUPOM NAO FISCAL", bold, Brushes.Black, 110, 80 );
    graphics.DrawLine( Pens.Black, 80, 100, 320, 100 );

    //print items
    graphics.DrawString( "COD | DESCRICAO                      | QTY | X | Vir Unit | Vir Total |", bold, Brushes.Black, 10, 120 );
    graphics.DrawLine( Pens.Black, 10, 140, 430, 140 );

    for( int i = 0; i < itemList.Count; i++ )
        graphics.DrawString( itemList[i].ToString(), regular, Brushes.Black, 20, 150 + i * 20 );

    //print footer


    // Check to see if more pages are to be printed.
    e.HasMorePages = ( itemList.Count > 20 );

Possible improvements on my example:

  • Centering the header strings could better be done using graphics.MeasureString().
  • List of items should better be a list of a business class insted of a plain string

Because this all is a lot of work, you should really consider using RDLC or some third party software to design your documents.

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