How to Get Current Drive's Free Disk Space in VB 4.0

• Professional and Enterprise Editions of Microsoft Visual Basic, 16-bit and 32-bit, for Windows, version 4.0

SUMMARY

This article shows how to find out how much free disk space is available on the current drive by calling the DiskSpaceFree function found in STKIT416.DLL for Win16 or STKIT432.DLL for Win32. Both dynamic-link libraries (DLLs) ship with the Setup kit in Microsoft Visual Basic version 4.0 for Windows. The DiskSpaceFree function is useful for finding the free space available on a drive. If you use the DiskSpaceFree function in your Visual Basic program, you need to distribute STKIT416.DLL or STKIT432.DLL to your customers.

MORE INFORMATION

There is also a function in the Win32 API (Application Programmers Interface) called GetDiskFreeSpace provided by the Win32 operating system that retrieves information about a specified disk, including the amount of free space on the disk. Refer to Method II in the example below. There are also other functions in the STKIT416.DLL or STKIT432.DLL that may be useful. You can use the AllocUnit function to get the disk allocation unit for the current drive, and use the SetTime function to set the destination file's date and time to the source file's date and time.

Examples of using these SETUPKIT functions are also included in the \VB\SETUPKIT\SETUP1\SETUP1.VBP project which is part of the SetupWizard.

Steps to Finding Out How Much Free Space Is Available on Drive C

1. Start a new project in Visual Basic. Form1 is created by default.

2. Add two Label controls (Label1 and Label2) and one Command button (Command1) to Form1.

3. Using the following table as a guide, set the properties of the controls you added in step 2.

      Control Name   Property       New Value
   

   Command1       Caption        Press for Free Space on Drive C
   Label1         AutoSize       True
   Label2         AutoSize       True

      #If Win32 Then
      Private Declare Function DiskSpaceFree Lib "STKIT432.DLL" Alias _
      "DISKSPACEFREE" () As Long
      Private Declare Function GetDiskFreeSpace Lib "kernel32" Alias _
      "GetDiskFreeSpaceA" ( ByVal lpRootPathName As String, _
      lpSectorsPerCluster As Long, lpBytesPerSector As Long, _
      lpNumberOfFreeClusters As Long, lpTotalNumberOfClusters As Long) _
      As Long
      #Else
      Private Declare Function DiskSpaceFree Lib "STKIT416.DLL" () As Long
      #End If

      Private Sub Command1_Click()
      Dim free_Space As Long
      ChDrive "C:"
      ' Method I (using the Win16 API).
      free_Space = DiskSpaceFree()
      Label1.Caption = "(Method I: ) The total free space on Drive C: = " _
      & Str$(free_Space) & " bytes"
      ' Method II (using the Win32 API).
      #If Win32 Then
      Dim numSectorsPerCluster As Long
      Dim numBytesPerSector As Long
      Dim numFreeClusters As Long
      Dim numTotalClusters As Long
      Dim success As Boolean
      success = GetDiskFreeSpace("C:\", numSectorsPerCluster, _
      numBytesPerSector,  numFreeClusters, numTotalClusters)
      free_Space = numSectorsPerCluster * numBytesPerSector * _
      numFreeClusters
      Label2.Caption = _
      "(Method II:) The total free space on Drive C: = " & _
      Str$(free_Space) & " bytes"
      #Else
      Label2.Caption = "Use Method I for Win16 applications"
      #End If
      End Sub