How to Mimic HIWORD, LOWORD, HIBYTE, LOBYTE C Macros in VB

MORE INFORMATION

The HIBYTE, LOBYTE, HIWORD, and LOWORD macros are defined in C in the WINDOWS.H file. The HIBYTE and LOBYTE macros are used to retrieve the high-order or low-order byte of the integer passed to them. The HIWORD and LOWORD macros retrieve the high-order or low-order word from a long integer value passed to them.

Step-by-Step Example

This example uses Visual Basic to mimic the HIBYTE, LOBYTE, HIWORD, and LOWORD macros

1. Start a new project in Visual Basic. Form1 is created by default.
2. Add two command buttons (Command1 and Command2) to Form1.
3. Add the following code to the Comamnd1_Click event:

      Sub Command1_Click ()
         Dim wParam As Integer
         Dim LOBYTE As Integer
         Dim HIBYTE As Integer
         ' Set wParam to a value:
         wParam = &H77FF
         ' Make call to function:
         ret = gethilobyte(wParam, LOBYTE, HIBYTE)
         ' Print out return values:
         Print LOBYTE, HIBYTE
      End Sub
   						

4. Add the following code to the Comamnd2_Click event:

      Sub Command2_Click ()
         Dim lParam As Long
         Dim LOWORD As Long
         Dim HIWORD As Long
         ' Set lParam to a value:
         lParam = &H7777FFFF
         ' Make call to function:
         ret = gethiloword(lParam, LOWORD, HIWORD)
         ' Print out return values:
         Print LOWORD, HIWORD
      End Sub
   						

5. Add the following code to the general declarations section of Form1:

      ' Enter the following Function statement as one, single line:
      Function gethilobyte(wparam as integer, LOBYTE as integer,
         HIBYTE as integer)
         ' This is the LOBYTE of the wParam:
         LOBYTE = wParam And  &HFF&
         ' This is the HIBYTE of the wParam:
         HIBYTE = wParam  \  &H100  And  &HFF&
         gethilobyte = 1
      End Function
   						

6. Add the following code to the general declarations section of Form1:

      Function gethiloword(lparam as long, LOWORD as long, HIWORD as long)
         ' This is the LOWORD of the lParam:
         LOWORD = lParam And  &HFFFF&
         ' LOWORD now equals 65,535 or &HFFFF
         ' This is the HIWORD of the lParam:
         HIWORD = lParam  \  &H10000  And  &HFFFF&
         ' HIWORD now equals 30,583 or &H7777
         gethiloword = 1
      End Function
   						

7. Run the program. Click the Command1 button to pull apart an integer value into its high-order and low-order bytes. Click the Command2 button to pull apart a long integer into its high-order and low-order words.