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How to print the content of a RichTextBox control by using Visual Basic .NET or Visual Basic 2005

For a Microsoft Visual Basic 6.0 version of this article, see 146022.
For a Microsoft Visual C# .NET version of this article, see 812425.
SUMMARY
This step-by-step article describes how to print the content of a RichTextBox control. The RichTextBox control does not provide a method to print its content. However, you can extend the RichTextBox class to use the EM_FORMATRANGE message. You can then send the content of a RichTextBox to an output device, such as a printer.

Create a RichTextBoxPrintCtrl control

To extend the RichTextBox class and use EM_FORMATRANGE to print the content of the RichTextBox control, follow these steps:
  1. Use Microsoft Visual Basic .NET or Microsoft Visual Basic 2005 to create a new Class Library project named RichTextBoxPrintCtrl.

    By default, Class1.vb is created.
  2. Change the name of the Class1.vb file to RichTextBoxPrintCtrl.vb.
  3. In the Solution Explorer, right-click References, and then click Add Reference.
  4. In the Add Reference dialog box, double-click System.Drawing.dll, and then double-click System.Windows.Forms.dll.
  5. To add references, click OK.
  6. Delete the existing code in RichTextBoxPrintCtrl.vb.
  7. Copy the following code to RichTextBoxPrintCtrl.vb:
    Option Explicit On Imports SystemImports System.Windows.FormsImports System.DrawingImports System.Runtime.InteropServicesImports System.Drawing.PrintingNamespace 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 ClassEnd Namespace
  8. To create RichTextBoxPrintCtrl.dll, click Build Solution on the Build menu.

Test the control

To test the control, follow these steps:
  1. Create a new Windows Application project by using Visual Basic .NET or Visual Basic 2005.

    By default, Form1.vb is created.
  2. From the Toolbox, drag a button onto Form1. Change the Name to btnPageSetup, and change the Text to Page Setup.
  3. From the Toolbox, drag another button onto Form1. Change the Name to btnPrintPreview, and change the Text to Print Preview.
  4. From the Toolbox, drag another button onto Form1. Change the Name to btnPrint, and change the Text to Print.
  5. In the Toolbox, double-click PrintDialog, double-click PrintPreviewDialog, double-click PrintDocument, and then double-click PageSetupDialog to add these controls to Form1.
  6. Modify the Document property of PrintDialog1, PrintPreviewDialog1, and PageSetupDialog1 to PrintDocument1.
  7. On the Tools menu, click Customize Toolbox.
  8. Click .NET Framework Components, click Browse, click to select RichTextBoxPrintCtrl.dll, and then click OK.
  9. From the Toolbox, drag RichTextBoxPrintCtrl onto Form1.
  10. In the Solution Explorer, right-click Form1.vb, and then click View Code.
  11. Add the following code to Class 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. To run the application, click Start on the Debug menu.
  13. Type text in RichTextBoxPrintCtrl.
  14. To set the page settings, click Page Setup.
  15. To see a preview of the page, click Print Preview.
  16. To print the content of the RichTextBoxPrintCtrl, click Print.
REFERENCES
For more information, visit the Microsoft .NET Framework Software Development Kit (SDK) Documentation or the following MSDN online Help Web site:
Properties

Article ID: 811401 - Last Review: 11/13/2007 09:46:36 - Revision: 5.5

Microsoft Visual Basic 2005, Microsoft Visual Basic .NET 2003 Standard Edition, Microsoft Visual Basic .NET 2002 Standard Edition

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