Speed up code and stop screen flickering:

Sub NoScreenRePainting()
Application.ScreenUpdating=False
  'Your code here.
Application.ScreenUpdating=True
End Sub

Preventing calculation while executing code:

Sub NoCalculations()
  Application.Calculation = xlCalculationManual
  'Your code here.
  Application.Calculation = xlCalculationAutomatic
End Sub

Speeding up code if you have Worksheet or Workbook Events. Also stops endless loops in Events

Sub StopAllEvents()
  Application.EnableEvents = False
  'Your code here.
  Application.EnableEvents = True
End Sub

Use the With Statement when working with Objects.

Sub WithARange()
  With Range("A1")
    .Value = 100
    .Font.Bold = True
    .Interior.ColorIndex = 6
    .Copy Destination:=Range("B1")
  End With
End Sub

Use VbNullString instead of = "" When needing to default a String variable back to it's default of "" use:

Sub EmptyText()
  Dim strWords As String
  strWords = "Cats"
  MsgBox strWords
  strWords = vbNullString
  MsgBox strWords
End Sub

Inserting a Relative formula into a range of cells: Faster than AutoFill or Copy.

Sub NoAutoFillOrCopy()
  Range("A1:A200").FormulaR1C1 = "=SUM(RC[1]:RC[5])"
End Sub

Tip: To get a formula, type it in any cell then select the cell, go Tools>Macro>Record new macro and record a macro pushing F2 then Enter.

Avoid the use of Copy and Paste whenever Possible:

Sub NoCopyAndPaste()
  'Instead of:
  Sheet1.Range("A1:A200").Copy
  Sheet2.Range("B1").pasteSpecial
  Application.CutCopyMode=False'Clear Clipboard
  'Use:
  'By-passes the Clipboard
  Sheet1.Range("A1:A200").Copy Destination:=Sheet2.Range("B1")
  'Or, if only values are needed:
  Sheet2.Range("B1:B200").Value= Sheet1.Range("A1:A200").Value
  'Or, if only formulae are needed:
  Sheet2.Range("B1:B200").Formula = Sheet1.Range("A1:A200").Formula
  'See also FormulaArray and FormulaR1C1 etc
  'Instead of:
  Sheet1.Range("A1:A200").Copy
  Sheet1.Range("A1:A200").PasteSpecial xlPasteValues
  Application.CutCopyMode=False'Clear Clipboard
  'Use:
  Sheet1.Range("A1:A200") = Sheet1.Range("A1:A200").Value
End Sub

Always declare your variables correctly!

To quickly view a variables definition:
Select the variable that you want the definition for.
Go to View>Definition (Shift+F2)

To return to your previous position:
Go to View>Last Postition (Ctrl+Shift+F2).

Release memory from Object variables:

Sub ReleaseObjectMemory()
  'Could be any variable of the Object type
  Dim wSheet as Worksheet
  'Set Object variable
  Set wSheet = Sheet1
  'Your code here.
  'Release memory
  Set wSheet = Nothing
End Sub

Don't get caught in the Loop.
Follow this link to see why Loops should (and usually can) be avoided.

Avoid If, Else whenever possible

More often than not people would use an If, Else Statement to test whether a condition is TRUE or FALSE. There is however a slightly faster (and less typing) method. The first example shows the common method, while the second shows a faster method. Of course in such a small example the difference is not noticeable.

Sub TrueOrFalseSlower()
  Dim bYesNo As Boolean
  Dim i As Integer
  If i = 5 Then
bYesNo = True
  Else
bYesNo = False
  End If
  MsgBox bYesNo
End Sub

Here's a better way!

Sub TrueOrFalseFaster()
  Dim bYesNo As Boolean
  Dim i As Integer
  bYesNo = (i = 5)
  MsgBox bYesNo
End Sub

Another common need is to toggle a variable between True and False depending on a condition. For example:

Sub ToggleTrueOrFalseSlower()
  Dim bYesNo As Boolean
  If bYesNo = False Then
bYesNo = True
  Else
bYesNo = False
  End If
  MsgBox bYesNo
End Sub

Here's a much better way

Sub ToggleTrueOrFalseFaster()
  Dim bYesNo As Boolean
  bYesNo = Not bYesNo
  MsgBox bYesNo
End Sub

Source: http://www.ozgrid.com/VBA/SpeedingUpVBACode.htm
posted on 2010-11-05 12:27  风生水起  阅读(368)  评论(0编辑  收藏  举报