Como: imprimir um arquivo de texto de várias páginas nos Windows Forms

É muito comum aplicativos do Windows imprimirem texto. A Graphics classe fornece métodos para desenhar objetos (gráficos ou texto) para um dispositivo, como uma tela ou impressora.

Imprimir texto

1. Adicione um PrintDocument componente e uma cadeia de caracteres ao formulário.

   private PrintDocument printDocument1 = new PrintDocument();
   private string stringToPrint;
   

   Private printDocument1 As New PrintDocument()
   Private stringToPrint As String
   

2. Se estiver imprimindo um documento, defina a propriedade para o documento que deseja imprimir e abra e leia o conteúdo do documento para a DocumentName cadeia de caracteres adicionada anteriormente.

   string docName = "testPage.txt";
   string docPath = @"c:\";
   printDocument1.DocumentName = docName;
   using (FileStream stream = new FileStream(docPath + docName, FileMode.Open))
   using (StreamReader reader = new StreamReader(stream))
   {
       stringToPrint = reader.ReadToEnd();
   }
   

   Dim docName As String = "testPage.txt"
   Dim docPath As String = "c:\"
   printDocument1.DocumentName = docName
   Dim stream As New FileStream(docPath + docName, FileMode.Open)
   Try
       Dim reader As New StreamReader(stream)
       Try
           stringToPrint = reader.ReadToEnd()
       Finally
           reader.Dispose()
       End Try
   Finally
       stream.Dispose()
   End Try
   

3. PrintPage No manipulador de eventos, use a Graphics propriedade da classe e o conteúdo do documento para calcular o PrintPageEventArgs comprimento da linha e as linhas por página. Depois que cada página for desenhada, verifique se é a última página e defina a HasMorePages PrintPageEventArgs propriedade do correspondente. O PrintPage evento é levantado até HasMorePages que seja false. Além disso, verifique se o PrintPage evento está associado ao seu método de manipulação de eventos.

   No exemplo de código a seguir, o manipulador de eventos é usado para imprimir o conteúdo do arquivo “testPage.txt” na mesma fonte usada no formulário.

   private void printDocument1_PrintPage(object sender, PrintPageEventArgs e)
   {
       int charactersOnPage = 0;
       int linesPerPage = 0;
   
       // Sets the value of charactersOnPage to the number of characters
       // of stringToPrint that will fit within the bounds of the page.
       e.Graphics.MeasureString(stringToPrint, this.Font,
           e.MarginBounds.Size, StringFormat.GenericTypographic,
           out charactersOnPage, out linesPerPage);
   
       // Draws the string within the bounds of the page
       e.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);
   }
   

   Private Sub printDocument1_PrintPage(ByVal sender As Object, _
       ByVal e As PrintPageEventArgs)
   
       Dim charactersOnPage As Integer = 0
       Dim linesPerPage As Integer = 0
   
       ' Sets the value of charactersOnPage to the number of characters 
       ' of stringToPrint that will fit within the bounds of the page.
       e.Graphics.MeasureString(stringToPrint, Me.Font, e.MarginBounds.Size, _
           StringFormat.GenericTypographic, charactersOnPage, linesPerPage)
   
       ' Draws the string within the bounds of the page
       e.Graphics.DrawString(stringToPrint, Me.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
   
   End Sub
   

4. Chame o método para gerar o Print PrintPage evento.

   printDocument1.Print();
   

   printDocument1.Print()
   

Exemplo

using System;
using System.Drawing;
using System.IO;
using System.Drawing.Printing;
using System.Windows.Forms;

namespace PrintApp
{
    public class Form1 : Form
    {
        private Button printButton;
        private PrintDocument printDocument1 = new PrintDocument();
        private string stringToPrint;
        public Form1()
        {
            this.printButton = new System.Windows.Forms.Button();
            this.printButton.Location = new System.Drawing.Point(12, 51);
            this.printButton.Size = new System.Drawing.Size(75, 23);
            this.printButton.Text = "Print";
            this.printButton.Click += new System.EventHandler(this.printButton_Click);
            this.ClientSize = new System.Drawing.Size(292, 266);
            this.Controls.Add(this.printButton);

            // Associate the PrintPage event handler with the PrintPage event.
            printDocument1.PrintPage +=
                new PrintPageEventHandler(printDocument1_PrintPage);
        }

        private void ReadFile()
        {
            string docName = "testPage.txt";
            string docPath = @"c:\";
            printDocument1.DocumentName = docName;
            using (FileStream stream = new FileStream(docPath + docName, FileMode.Open))
            using (StreamReader reader = new StreamReader(stream))
            {
                stringToPrint = reader.ReadToEnd();
            }
        }

        private void printDocument1_PrintPage(object sender, PrintPageEventArgs e)
        {
            int charactersOnPage = 0;
            int linesPerPage = 0;

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

            // Draws the string within the bounds of the page
            e.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);
        }

        private void printButton_Click(object sender, EventArgs e)
        {
            ReadFile();
            printDocument1.Print();
        }

        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }
}

Imports System.Drawing
Imports System.IO
Imports System.Drawing.Printing
Imports System.Windows.Forms

Public Class Form1
    Inherits Form
    Private printButton As Button

    Private printDocument1 As New PrintDocument()
    Private stringToPrint As String

    Public Sub New() 
        Me.printButton = New System.Windows.Forms.Button()
        Me.printButton.Location = New System.Drawing.Point(12, 51)
        Me.printButton.Size = New System.Drawing.Size(75, 23)
        Me.printButton.Text = "Print"
        Me.ClientSize = New System.Drawing.Size(292, 266)
    End Sub

    Private Sub ReadFile() 
        Dim docName As String = "testPage.txt"
        Dim docPath As String = "c:\"
        printDocument1.DocumentName = docName
        Dim stream As New FileStream(docPath + docName, FileMode.Open)
        Try
            Dim reader As New StreamReader(stream)
            Try
                stringToPrint = reader.ReadToEnd()
            Finally
                reader.Dispose()
            End Try
        Finally
            stream.Dispose()
        End Try
    End Sub
    
    Private Sub printDocument1_PrintPage(ByVal sender As Object, _
        ByVal e As PrintPageEventArgs)

        Dim charactersOnPage As Integer = 0
        Dim linesPerPage As Integer = 0

        ' Sets the value of charactersOnPage to the number of characters 
        ' of stringToPrint that will fit within the bounds of the page.
        e.Graphics.MeasureString(stringToPrint, Me.Font, e.MarginBounds.Size, _
            StringFormat.GenericTypographic, charactersOnPage, linesPerPage)

        ' Draws the string within the bounds of the page
        e.Graphics.DrawString(stringToPrint, Me.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

    End Sub

    Private Sub printButton_Click(ByVal sender As Object, ByVal e As EventArgs) 
        ReadFile()
        printDocument1.Print()
    End Sub

    
    <STAThread()>  _
    Shared Sub Main() 
        Application.EnableVisualStyles()
        Application.SetCompatibleTextRenderingDefault(False)
        Application.Run(New Form1())
    End Sub
End Class

Compilando o código

Este exemplo requer:

• Um arquivo de texto chamado testPage.txt contendo o texto a ser impresso, localizado na raiz da unidade C:\. Edite o código para imprimir um arquivo diferente.

• Referências aos assemblies System, System.Windows.Forms e System.Drawing.

• Para obter informações sobre como criar este exemplo a partir da linha de comando para Visual Basic ou Visual C#, consulte Compilando a partir da linha de comando ou Criando linha de comando com csc.exe. Você também pode criar este exemplo no Visual Studio colando o código em um novo projeto.

Confira também

• Graphics
• Brush
• Suporte à impressão nos Windows Forms