Практическое руководство. Печать многостраничных текстовых файлов в Windows Forms

Статья
11/05/2008

Обновлен: Ноябрь 2007

В приложениях Windows очень часто используется печать текста. Класс Graphics предоставляет методы для рисования объектов (графических или текстовых) на устройствах, таких как экран или принтер.

Примечание.
Методы DrawText класса TextRenderer не поддерживаются для печати. Для рисования текста для печати следует всегда использовать методы DrawString класса Graphics, как показано в следующем примере кода.

Чтобы напечатать текст, выполните следующие действия.

Добавьте в форму компонент PrintDocument и строку.

Private printDocument1 As New PrintDocument()
Private stringToPrint As String

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

При печати задайте для документа, который требуется напечатать, свойство DocumentName, и затем откройте и прочтите содержимое документа до добавленной ранее строки.

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

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();
}

В обработчике события PrintPage используйте свойство Graphics класса PrintPageEventArgs и содержимое документа, чтобы вычислить длину строки и число строк на страницу. Нарисовав очередную страницу, проверьте, является ли она последней страницей, и установите соответствующим образом свойство HasMorePages класса PrintPageEventArgs. Событие PrintPage возникает до тех пор, пока значение свойства HasMorePages не равно false. Кроме того, убедитесь, что событие PrintPage связано со своим методом обработки событий.

В следующем примере кода обработчик событий используется для печати содержимого файла "testPage.txt" тем шрифтом, который используется в форме.

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 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);
}

Вызовите метод Print для инициации события PrintPage.
```
printDocument1.Print()
```
```
printDocument1.Print();
```

Пример

Imports System
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

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());
        }
    }
}