Adit Cookbook Pages

Bits and Bobs

Accessing Environment Variables

A little out of date but still useful stuff - particularly under NT and Windows 2000 where these can be set by user rather than just for the machine. Do remember that environment variables are case sensitive. This code sample assumes that the environment variable set is MYENV and that it is a path to an application data set.

Dim EnvValue as String  

   EnvValue = Environ$("MYENV")
   If EnvValue = "" Then
       EnvValue = "C:\DEFAULTFOLDER\"
   End If

   If Right$(EnvValue, 1) <> "\" Then
       EnvValue = EnvValue + "\"
   End If
 

Numeric Entry to a Text Box

You can call this routine from the KeyPress event of any text box by placing a line in the event code that looks like:

Private Sub Text1_KeyPress(KeyAscii As Integer)
   KeyAscii = NumericOnly(KeyAscii)
End Sub
 

and the routine looks like this:

Public Function NumericOnly(KeyAscii As Integer) As Integer
   If Not IsNumeric(Chr$(KeyAscii)) And Not KeyAscii = vbKeyBack Then
       NumericOnly = 0
   Else
       NumericOnly = KeyAscii
   End If
End Function

Of course sometimes you want the user to be able to enter decimal points, minus signs or even currency symbols so how about:

Public Function NumericOnly(KeyAscii As Integer, Optional extrachar As Variant) As Integer
   Select Case Chr$(KeyAscii)
       Case "0" To "9", Chr$(vbKeyBack)
           NumericOnly = KeyAscii
       Case Else
           NumericOnly = 0
           If Not IsMissing(extrachar) Then
               If InStr(extrachar, Chr$(KeyAscii)) Then
                   NumericOnly = KeyAscii
               End If
           End If
   End Select
End Function
 

You just pass any optional characters in the extrachar variable. You can omit the variable if none are required in a given instance.

Adding Lines to a MsgBox message

If you need to build up a message string for a message box - perhaps while doing some validation you might want to separate new additions onto a new line within the message box. You could keep testing the string to see if it has any existing content and then add a linefeed character if it has.

Your code might look like this in a number of places in the validation routine:

    If Msg > "" then
        Msg = Msg & vbLF & "Found yet another fault"
    Else
        Msg = "Found yet another fault"
    End If

The alternative is to append the function below and then use something like:

    Msg = AddLines(Msg, "Found a Fault")

Private Function AddLines(ByVal TargetString As String, ByVal NewLineString As_ String) As String
    If TargetString > "" Then
        TargetString = TargetString & vbLf
    End If
    TargetString = TargetString & NewLineString
    AddLines = TargetString
End Function

Ascii Codes

For a full list of the default ascii codes click here. The quick reference below will help in most instances. Select, cut and paste it somewhere handy.