Kill
Firstly, since I use it in almost every function which uses objects, I thought I'd better repost Kill(), which tidies up objects and arrays, with special handling for ADO and Dictionary objects.
NOTE: All code posted on this blog from now on will assume that this function is part of your includes
Function Kill(byref Obj)
Select Case True
Case IsObject(Obj)
Select Case LCase(TypeName(Obj))
Case "recordset", "command", "stream", "connection"
'ADO objects
If Obj.State <> 0 then
Obj.Close
End If
case "dictionary"
'remove all the pairs
Obj.RemoveAll
Case else
'something else so don't
'do anything special
End Select
Set Obj = Nothing
Case IsArray(Obj)
'clear the array
Erase Obj
Case Else
'do nothing at all
End Select
'Now revert it to an unitialized state
Obj = Empty
End Function
IsBlank
This is another of my most frequently used snippets, which acts as a catch-all checker for variables, meaning that you no longer have to worry about the variable type when you want to use a If MyVar="" Then statement. It will automatically test the variable using all the appropriate checks - see the code for exactly what it does and how. Simple, but remarkably handy! Give it a go next time you write a complicated script or entire app!
NOTE: All code posted on this blog from now on will assume that this function is part of your includes
Function IsBlank(ByRef Var)
IsBlank = False
Select Case True
Case IsObject(Var)
If var Is Nothing Then
IsBlank = True
End If
Case IsEmpty(Var), IsNull(Var)
IsBlank = True
Case IsArray(Var)
If UBound(Var) = 0 Then
IsBlank = True
End If
Case IsNumeric(Var)
If (Var = 0) Then
IsBlank = True
End If
Case Else
If Trim(Var) = "" Then
IsBlank = True
End If
End Select
End Function
ToggleVariable
Invaluable for all sorts of situations where variable needs to flip-flop between two values - one example being alternating colours for table rows.
'Toggles a variable between two values, and will initalise
'the variable to the "on" state if it doesn't have either value
Function ToggleVariable(Byref Variable, ByVal StateOn, ByVal StateOff)
If (Variable = StateOn) Then
Variable = StateOff
Else
Variable = StateOn
End If
ToggleVariable = Variable
End Function
For example:For N = 1 To 10
Response.Write "<" & "tr bgcolor=""" & ToggleVariable(C, "#ffaaaa", "#aaffaa") & """>"
Response.Write "<" & "td>" & N & "<" & "/td>"
Response.Write "<" & "/tr>"
Next
(tags are broken up to circumvent posting problems in this blog)
Note that although it's a function which returns the new value, it does directly modify the variable (because it's passed ByRef) and therefore can be called as a sub too:
For N = 1 To 10
Call ToggleVariable(OddRowIndicator, True, False)
If (OddRowIndicator = True) Then
'do something here
End If
Next
GetCurrentURL
Sometimes it's handy to know what the current URL is within your script, but strangely enough ASP doesn't expose this information directly, instead it must be assembled from various server variables. Here's a little function which does it for you:
Function GetCurrentURL()
'Select the protocol
If request.servervariables("HTTPS") = "on" Then
GetCurrentURL = "https://"
Else
GetCurrentURL = "http://"
End If
GetCurrentURL = GetCurrentURL & Request.ServerVariables("SERVER_NAME")
If (Request.ServerVariables("SERVER_PORT") <> 80) Then
GetCurrentURL = GetCurrentURL & ":" & Request.ServerVariables("SERVER_PORT")
End If
GetCurrentURL = GetCurrentURL & Request.ServerVariables("URL")
If (Request.QueryString <> "") Then
GetCurrentURL = GetCurrentURL & "?" & Request.QueryString
End If
End Function
IIf
And last but not least here's, a handy VBScript version of a VB statement which is also commonly used as a macro in C/C++. This snippet lets you condense a simple "If...Then...Else...End If" block into a single line.
'Immediate If
Function IIf(Condition, ValueIfTrue, ValueIfFalse)
If Condition Then
IIf = ValueIfTrue
Else
IIf = ValueIfFalse
End if
End Function
For example, you could turn this:
If IsNull(Price) Then
Response.Write "(n/a)"
Else
Response.Write Price
End If
Into this:
Response.Write IIF(IsNull(Price), "(n/a)", Price)
However, let me just make you aware of a slight caveat that presents itself when using this shorthand form...
Let's say that we wanted to format the price as a number with 2 decimal places - one might naturally use FormatNumber(Price, 2) to do this and insert it into the code like so:Response.Write IIF(IsNull(Price), "(n/a)", FormatNumber(Price, 2))
Unfortunately, this won't work. When you call a function or sub, all parameters are passed either ByRef or ByVal, but regardless it is either a variable (which may contain an object, array, or value) or a value which is passed. Therefore, all three parameters to the IIF function are evaluated before the function is called, and the resulting values are passed.
The consequence of this is that if the variable Price is ever Null, the script will throw an error, because FormatNumber() chokes on Nulls. Therefore, be careful about how you use this and remember that is not quite a 1:1 replacement for the full statement block.
That's all for now, if you have any questions please post a comment and I'll be sure to answer it.]]>