Como imprimir o conteúdo de um controle RichTextBox usando Visual Basic .NET ou Visual Basic 2005

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Criar um controle RichTextBoxPrintCtrl

1. Use o Microsoft Visual Basic .NET ou Microsoft Visual Basic 2005 para criar uma nova classe projeto Library chamado RichTextBoxPrintCtrl .
   
   Por padrão, Class1.vb é criado.
2. Altere o nome do arquivo Class1.vb para RichTextBoxPrintCtrl.vb .
3. No Solution Explorer, clique com o botão direito do mouse em References e, em seguida, clique em Add Reference .
4. Na caixa de diálogo Add Reference , clique duplo em System.Drawing.dll e, em seguida, clique duas vezes em System.Windows.Forms.dll .
5. Para adicionar referências, clique em OK .
6. Exclua o código existente no RichTextBoxPrintCtrl.vb .
7. Copy the following code to RichTextBoxPrintCtrl.vb:

   Option Explicit On 
   
   Imports System
   Imports System.Windows.Forms
   Imports System.Drawing
   Imports System.Runtime.InteropServices
   Imports System.Drawing.Printing
   
   Namespace RichTextBoxPrintCtrl
      Public Class RichTextBoxPrintCtrl
         Inherits RichTextBox
         ' Convert the unit that is used by the .NET framework (1/100 inch) 
         ' and the unit that is used by Win32 API calls (twips 1/1440 inch)
         Private Const AnInch As Double = 14.4
   
         <StructLayout(LayoutKind.Sequential)> _
          Private Structure RECT
            Public Left As Integer
            Public Top As Integer
            Public Right As Integer
            Public Bottom As Integer
         End Structure
   
         <StructLayout(LayoutKind.Sequential)> _
         Private Structure CHARRANGE
            Public cpMin As Integer          ' First character of range (0 for start of doc)
            Public cpMax As Integer          ' Last character of range (-1 for end of doc)
         End Structure
   
         <StructLayout(LayoutKind.Sequential)> _
         Private Structure FORMATRANGE
            Public hdc As IntPtr             ' Actual DC to draw on
            Public hdcTarget As IntPtr       ' Target DC for determining text formatting
            Public rc As Rect                ' Region of the DC to draw to (in twips)
            Public rcPage As Rect            ' Region of the whole DC (page size) (in twips)
            Public chrg As CHARRANGE         ' Range of text to draw (see above declaration)
         End Structure
   
         Private Const WM_USER As Integer = &H400
         Private Const EM_FORMATRANGE As Integer = WM_USER + 57
   
         Private Declare Function SendMessage Lib "USER32" Alias "SendMessageA" (ByVal hWnd As IntPtr, ByVal msg As Integer, ByVal wp As IntPtr, ByVal lp As IntPtr) As IntPtr
   
         ' Render the contents of the RichTextBox for printing
         '	Return the last character printed + 1 (printing start from this point for next page)
         Public Function Print(ByVal charFrom As Integer, ByVal charTo As Integer, ByVal e As PrintPageEventArgs) As Integer
   
            ' Mark starting and ending character 
            Dim cRange As CHARRANGE
            cRange.cpMin = charFrom
            cRange.cpMax = charTo
   
            ' Calculate the area to render and print
            Dim rectToPrint As RECT
            rectToPrint.Top = e.MarginBounds.Top * AnInch
            rectToPrint.Bottom = e.MarginBounds.Bottom * AnInch
            rectToPrint.Left = e.MarginBounds.Left * AnInch
            rectToPrint.Right = e.MarginBounds.Right * AnInch
   
            ' Calculate the size of the page
            Dim rectPage As RECT
            rectPage.Top = e.PageBounds.Top * AnInch
            rectPage.Bottom = e.PageBounds.Bottom * AnInch
            rectPage.Left = e.PageBounds.Left * AnInch
            rectPage.Right = e.PageBounds.Right * AnInch
   
            Dim hdc As IntPtr = e.Graphics.GetHdc()
   
            Dim fmtRange As FORMATRANGE
            fmtRange.chrg = cRange                 ' Indicate character from to character to 
            fmtRange.hdc = hdc                     ' Use the same DC for measuring and rendering
            fmtRange.hdcTarget = hdc               ' Point at printer hDC
            fmtRange.rc = rectToPrint              ' Indicate the area on page to print
            fmtRange.rcPage = rectPage             ' Indicate whole size of page
   
            Dim res As IntPtr = IntPtr.Zero          
   
            Dim wparam As IntPtr = IntPtr.Zero
            wparam = New IntPtr(1)
   
            ' Move the pointer to the FORMATRANGE structure in memory
            Dim lparam As IntPtr = IntPtr.Zero
            lparam = Marshal.AllocCoTaskMem(Marshal.SizeOf(fmtRange))
            Marshal.StructureToPtr(fmtRange, lparam, False)
   
            ' Send the rendered data for printing 
            res = SendMessage(Handle, EM_FORMATRANGE, wparam, lparam)
   
            ' Free the block of memory allocated
            Marshal.FreeCoTaskMem(lparam)
   
            ' Release the device context handle obtained by a previous call
            e.Graphics.ReleaseHdc(hdc)
   
            ' Return last + 1 character printer
            Return res.ToInt32()
         End Function
   
      End Class
   End Namespace
   

8. Para criar RichTextBoxPrintCtrl.dll , clique em Build Solution no menu Build .

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Testar o controle

1. Crie um novo projeto Windows Application usando Visual Basic .NET ou Visual Basic 2005.
   
   Por padrão, Form1.vb é criado.
2. A partir da caixa de ferramentas, arraste um botão para Form1. Altere o nome para btnPageSetup e altere o texto para Configurar página .
3. A partir da caixa de ferramentas, arraste o outro botão para Form1. Altere o nome para btnPrintPreview e altere o texto para Visualização .
4. A partir da caixa de ferramentas, arraste o outro botão para Form1. Altere o nome para btnPrint e altere o texto para impressão .
5. Na caixa de ferramentas, clique duas vezes em PrintDialog , clique duas vezes em PrintPreviewDialog , clique duas vezes em PrintDocument e, em seguida, clique duas vezes PageSetupDialog para adicionar esses controles para Form1.
6. Modifica a propriedade Document de PrintDialog1 , PrintPreviewDialog1 e PageSetupDialog1 para PrintDocument1 .
7. No menu Ferramentas , clique em Customize Toolbox .
8. Clique em .NET Framework Components , clique em Procurar , clique para selecionar RichTextBoxPrintCtrl.dll e, em seguida, clique em OK .
9. Na caixa de ferramentas, arraste RichTextBoxPrintCtrl para Form1.
10. Na Solution Explorer, clique com o botão direito do mouse em Form1.vb e, em seguida, clique em View Code .
11. Adicione o seguinte código à classe Form1:

       Private checkPrint As Integer
    
       Private Sub PrintDocument1_BeginPrint(ByVal sender As Object, ByVal e As System.Drawing.Printing.PrintEventArgs) Handles PrintDocument1.BeginPrint
          checkPrint = 0
       End Sub
    
       Private Sub PrintDocument1_PrintPage(ByVal sender As Object, ByVal e As System.Drawing.Printing.PrintPageEventArgs) Handles PrintDocument1.PrintPage
          ' Print the content of the RichTextBox. Store the last character printed.
          checkPrint = RichTextBoxPrintCtrl1.Print(checkPrint, RichTextBoxPrintCtrl1.TextLength, e)
    
          ' Look for more pages
          If checkPrint < RichTextBoxPrintCtrl1.TextLength Then
             e.HasMorePages = True
          Else
             e.HasMorePages = False
          End If
       End Sub
    
       Private Sub btnPageSetup_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPageSetup.Click.Click
          PageSetupDialog1.ShowDialog()
       End Sub
    
       Private Sub btnPrint_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPrint.Click
          If PrintDialog1.ShowDialog() = DialogResult.OK Then
             PrintDocument1.Print()
          End If
       End Sub
    
       Private Sub btnPrintPreview_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPrintPreview.Click
          PrintPreviewDialog1.ShowDialog()
       End Sub

12. Para executar o aplicativo, clique em Iniciar no menu Debug .
13. Digite texto na RichTextBoxPrintCtrl .
14. Para definir as configurações de página, clique em Configurar página .
15. Para ver uma visualização da página, clique em impressão visualizar .
16. Para imprimir o conteúdo da RichTextBoxPrintCtrl , clique em Imprimir .

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