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Visual Basic File Routines Pure VB: Combine Multiple Elements into a Single File |
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Posted: | Sunday May 07, 2000 | |
Updated: | Monday December 26, 2011 | |
Applies to: | VB3, VB4-32, VB5, VB6 | |
Developed with: | VB6, Windows NT4 | |
OS restrictions: | None | |
Author: | Larry Serflaten, VBnet - Randy Birch | |
Related: |
Pure VB: Combine a Picture and Text into a Single File RegSetValueEx: Create a Registered File Association |
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Prerequisites |
None. |
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The
basic code above saved an picture and textbox data into a combined file.
The principle behind doing this can easily be extended to accommodate
pretty well any type of file data. In this example a picture, as well as
the contents of three Rich Text boxes, are saved to the composite-data
file.
In order to accommodate the file offset values required to track the data's position within the file, and to make handling those values easier in code, I've changed the method of saving a Long offset into saving a UDT containing variables for all the data required. This also facilitates extending this metaphor to handle any number of controls. To create the demo load any image into a picture box. To show how the Rich Text formatting is preserved when saved to the composite file, I've set the Rich Text strings in the Form Load event to create the RTF contents shown in the illustration. The RTF formatting of these string necessitate a somewhat wider page than I prefer. The listbox data shown is strictly debugging only and is not required in production; it shows the relative values retrieved by the UDT in the first step of the Extract method. |
BAS Module Code |
None. |
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Form Code |
To a form, add a picture box (Picture1), a list box (List1), and three Rich Text controls (RichTextBox1, RichTextBox2 and RichTextBox3). Load an image of your choice into Picture1. The code below populates the RTF controls. Add three command buttons (Command1, Command2, and Command3) along with the following code: |
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Option Explicit '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' Copyright ©1996-2011 VBnet/Randy Birch, All Rights Reserved. ' Some pages may also contain other copyrights by the author. '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' Distribution: You can freely use this code in your own ' applications, but you may not reproduce ' or publish this code on any web site, ' online service, or distribute as source ' on any media without express permission. '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' Private Type MultiFileStoreData imgStart As Long imgSize As Long txt1Start As Long txt1Size As Long txt2Start As Long txt2Size As Long txt3Start As Long txt3Size As Long End Type Const sPicFileSource = "vbnlogo.gif" Const sCombinedFile = "combined.dat" Const sTmpPix = "tmp.gif" Private Sub Form_Load() Picture1.Picture = LoadPicture(sPicFileSource) RichTextBox1 = "{\rtf1\ansi\ansicpg1252\deff0\deftab720{\fonttbl{\f0\fswiss MS Sans Serif;}" & _ "{\f1\froman\fcharset2 Symbol;}{\f2\froman Times New Roman;}}" & _ "{\colortbl\red0\green0\blue0;\red0\green0\blue255;\red255\green0\blue0;}" & _ "\deflang1033\pard\plain\f0\fs16\cf0 Welcome to " & _ "\plain\f0\fs16\cf1\b VBnet\plain\f0\fs16\cf0," & _ " providing the enhanced functionality of the " & _ "\plain\f0\fs16\cf2\b win32 api \plain\f0\fs16\cf0" & _ " to \plain\f0\fs16\cf0\i\ul intermediate and advanced " & _ "visual basic developers\plain\f0\fs16\cf0." & _ "\plain\f2\fs20 \par}" RichTextBox2 = "{\rtf1\ansi\ansicpg1252\deff0\deftab720{\fonttbl{\f0\fswiss MS Sans Serif;}" & _ "{\f1\froman\fcharset2 Symbol;}{\f2\froman Times New Roman;}" & _ "{\f3\fswiss\fprq2 MS Sans Serif;}}" & _ "{\colortbl\red0\green0\blue0;}" & _ "\deflang1033\pard\plain\f3\fs16\cf0 All code is provided " & _ "free of charge.\plain\f2\fs20 \par}" RichTextBox3 = "{\rtf1\ansi\ansicpg1252\deff0\deftab720{\fonttbl{\f0\fswiss MS Sans Serif;}" & _ "{\f1\froman\fcharset2 Symbol;}{\f2\froman Times New Roman;}" & _ "{\f3\fswiss\fprq2 MS Sans Serif;}}" & _ "{\colortbl\red0\green0\blue0;\red128\green0\blue128;\red255\green0\blue0;}" & _ "\deflang1033\pard\plain\f3\fs16\cf0 Remember to visit the \plain\f3\fs16\cf2 links" & _ " \plain\f3\fs16\cf0 on the \plain\f3\fs16\cf1 mvps.org\plain\f3\fs16\cf0 and " & _ "\plain\f3\fs16\cf1 Best Links \plain\f3\fs16\cf0 pages.\plain\f2\fs20 \par}" End Sub Private Sub Command1_Click() Dim hFile As Long Dim tmp As String Dim mfs As MultiFileStoreData 'save the picture portion as the first entry 'in the "combined file" SavePicture Picture1.Picture, sCombinedFile 'Open the combined file for Binary to 'add the text to file hFile = FreeFile Open sCombinedFile For Binary As #hFile 'Retrieve the size of the image into a 'variable for later use, then append the 'text from Richtext1 into the same file 'and close it. mfs.imgStart = 1 mfs.imgSize = LOF(hFile) With RichTextBox1 .SelStart = 0 .SelLength = Len(.Text) tmp = .SelRTF mfs.txt1Start = mfs.imgSize + 1 mfs.txt1Size = Len(tmp) Seek #hFile, mfs.txt1Start Put #hFile, , tmp End With With RichTextBox2 .SelStart = 0 .SelLength = Len(.Text) tmp = .SelRTF mfs.txt2Start = mfs.txt1Start + mfs.txt1Size + 1 mfs.txt2Size = Len(tmp) Seek #hFile, mfs.txt2Start Put #hFile, , tmp End With With RichTextBox3 .SelStart = 0 .SelLength = Len(.Text) tmp = .SelRTF mfs.txt3Start = mfs.txt2Start + mfs.txt2Size + 1 mfs.txt3Size = Len(tmp) Seek #hFile, mfs.txt3Start Put #hFile, , tmp End With 'The file now contains both the image 'and text file. As a final step, we 'save the length of image retrieved 'above as the last item in the file. 'Its just a matter of writing the 'UDT to the end of the file. Seek #hFile, LOF(hFile) Put #hFile, LOF(hFile) + 1, mfs Close #hFile End Sub Private Sub Command2_Click() Set Picture1.Picture = Nothing List1.Clear RichTextBox1 = "" RichTextBox2 = "" RichTextBox3 = "" End Sub Private Sub Command3_Click() Dim hFile As Long Dim hFileOut As Long Dim PicData() As Byte Dim mfs As MultiFileStoreData 'First step in the extraction process is to 'obtain the length of image portion saved 'as the last item in the file. hFile = FreeFile Open sCombinedFile For Binary As #hFile 'move to the EOF - the UDT size and load 'saved UDT data Seek #hFile, LOF(hFile) - (Len(mfs) - 1) Get #hFile, , mfs List1.AddItem mfs.imgStart & vbTab & mfs.imgSize & vbTab & mfs.imgSize List1.AddItem mfs.txt1Start & vbTab & mfs.txt1Size & vbTab & mfs.txt1Start + mfs.txt1Size List1.AddItem mfs.txt2Start & vbTab & mfs.txt2Size & vbTab & mfs.txt2Start + mfs.txt3Size List1.AddItem mfs.txt3Start & vbTab & mfs.txt3Size & vbTab & mfs.txt3Start + mfs.txt3Size 'with the image size, create a byte array 'large enough to accommodate the image ReDim PicData(0 To mfs.imgSize - 1) As Byte 'and load the image data, repositioning the 'file pointer to the beginning first Seek #hFile, 1 Get #hFile, , PicData() 'write the retrieved file out to a temporary 'file in order to use the LoadPicture method. hFileOut = FreeFile Open sTmpPix For Binary As #hFileOut Put #hFileOut, , PicData() Close #hFileOut 'load the text portions to the rich text controls. Seek #hFile, mfs.txt1Start RichTextBox1.SelRTF = Input(mfs.txt1Start + mfs.txt1Size, #hFile) Seek #hFile, mfs.txt2Start RichTextBox2.SelRTF = Input(mfs.txt2Start + mfs.txt3Size, #hFile) Seek #hFile, mfs.txt3Start RichTextBox3.SelRTF = Input(mfs.txt3Start + mfs.txt3Size, #hFile) Close #hFile 'Load the saved image from the tmp file 'and kill it Picture1 = LoadPicture(sTmpPix) Kill sTmpPix End Sub |
Comments |
Assure the paths and files are valid for your system. |
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Copyright ©1996-2011 VBnet and Randy Birch. All Rights Reserved. |