HOWTO: Use LoadResData with Binary Data

• Microsoft Visual Basic Professional and Enterprise Editions for Windows, version 4.0

SUMMARY

Visual Basic 4.0 introduces a new function called LoadResData, which can be used to retrieve binary data from a resource (.res) file. The sample in this document demonstrates how to create a resource file and use binary data from it in all versions of Visual Basic 4.0.

MORE INFORMATION

The following code is a resource script that can be compiled by using the 16-bit and 32-bit versions of Rc.exe.

    ////////////////////////////////////////////////////////////////////// 
    ////// 
    // Myres.rc - 16 & 32 bit script. This must be compiled into two                        
    //.res files using the 16 & 32 bit versions of RC.
    /////////////////////////////////////////////////////////////////////// 
    ////// 
    // Wave Resources - You must copy these files from your \Windows
    // directory to the directory where your .rc script resides.

     CHIMES                  WAVE    DISCARDABLE     "Chimes.wav"
     DING                    WAVE    DISCARDABLE     "Ding.wav"
 

Steps to Create a Resource File

1. Save the preceding code in Notepad as Myres.rc in the directory where Rc.exe exists on your hard disk.



2. Copy Chimes.wav and Ding.wav from your Windows directory (or your \Windows\Media directory on Windows 95 or Windows 98) to the same directory where you saved the Myres.rc file.



3. At the command line, type "RC -r Myres.rc." If you want a 16-bit and 32- bit version of your resource file, then you will have to save two copies of your resource file as Myres32.rc and Myres16.rc, and compile each separately with the appropriate resource compiler.

Steps to Run the Sample Application

1. Create a new project and add a command button to Form1.



2. Add the following code to Form1:

   
   '*********************************************************************
   
         ' Form1.frm - Calls PlayWaveRes to play a wave resource file.
   
   '*********************************************************************
   
         Sub Command1_Click()
            PlayWaveRes "Chimes"
            PlayWaveRes "Ding"
         End Sub 




3. Add your resource file to the project.



4. Type the following code in a new code module:

   
   **********************************************************************
   
         ' Baswave.bas - Plays a wave file from a resource using LoadResData.
   
   '*********************************************************************
   
         Option Explicit
         #If Win32 Then
           Private Declare Function sndPlaySound Lib "winmm" Alias _
              "sndPlaySoundA" (lpszSoundName As Any, ByVal uFlags As Long) _
              As Long
         #Else
           Private Declare Function sndPlaySound Lib "MMSYSTEM" ( _
                              lpszSoundName As Any, ByVal uFlags%) As Integer
         #End If
   
   '*********************************************************************
   
         ' Flag values for wFlags parameter.
   
   '*********************************************************************
   
         Public Const SND_SYNC = &H0        ' Play synchronously (default).
         'Public Const SND_ASYNC = &H1      ' Play asynchronously (see
                                            ' note below).
         Public Const SND_NODEFAULT = &H2   ' Do not use default sound.
         Public Const SND_MEMORY = &H4      ' lpszSoundName points to a
                                            ' memory file.
         Public Const SND_LOOP = &H8        ' Loop the sound until next
                                            ' sndPlaySound.
         Public Const SND_NOSTOP = &H10     ' Do not stop any currently
                                            ' playing sound.
   
   '*********************************************************************
   
         ' Plays a wave file from a resource.
   
   '*********************************************************************
   
         Public Sub PlayWaveRes(vntResourceID As Variant, Optional vntFlags)
         '-----------------------------------------------------------------
         ' WARNING:  If you want to play sound files asynchronously in
         '           Win32, then you MUST change bytSound() from a local
         '           variable to a module-level or static variable. Doing
         '           this prevents your array from being destroyed before
         '           sndPlaySound is complete. If you fail to do this, you
         '           will pass an invalid memory pointer, which will cause
         '           a GPF in the Multimedia Control Interface (MCI).
         '-----------------------------------------------------------------
         Dim bytSound() As Byte ' Always store binary data in byte arrays!
   
         bytSound = LoadResData(vntResourceID, "WAVE")
   
         If IsMissing(vntFlags) Then
            vntFlags = SND_NODEFAULT Or SND_SYNC Or SND_MEMORY
         End If
   
         If (vntFlags And SND_MEMORY) = 0 Then
            vntFlags = vntFlags Or SND_MEMORY
         End If
   
         sndPlaySound bytSound(0), vntFlags
         End Sub 

REFERENCES

For information on how to store any file type in a resource file and retrieve the file for use at run-time in Visual Basic versions 5.0 and 6.0, please see the following article in the Microsoft Knowledge Base:

Q194409SAMPLE: RESFILE.EXE Stores Any File Type in a Resource File

Additional query words: WAVE LOADRESDATA RESOURCES RC BYTE SND_ASYNC kbdsd

Keywords : kbcode kbnokeyword kbVBp400 kbGrpVB
Version : WINDOWS:4.0
Platform : WINDOWS
Issue type : kbhowto