Keeping the user informed is important
If you have written some VBA code for Excel (or Word, or Access), and it takes a long time to execute, it is important to keep the user informed that the code is progressing. Psychologically, it can also have a tremendously positive effect on the perceived responsiveness and speed of your program if the user can see a visual representation of the current progress.

Common methods of keeping the user informed
Currently, a lot of people keep the user informed by allowing the actions of the macro to be seen. (i.e., the flicker of sheets being activated, cells being changed, etc...). This is generally a terrible idea unless the whole routine is finished very quickly. Excel experts should have learned by now that by setting Application.ScreenUpdating = False as the first step to a VBA routine can speed up code execution by orders of magnitude. The only problem with this, is that now the program appears to be frozen until the code sets screen updating back to true. If this takes a long time, the user might think excel is frozen.

Now that Excel's interface is frozen to speed up procedures, it's especially important to inform the user. Many people do this by setting the value of Application.StatusBar. This can hold any text, and updates even when screen updating is disabled. By changing this regularly, the programmer can give a play by play of the current position in the code, or display a percentage completion in a large loop.
 
Prog-Status-Bar.PNG (3 KB) (File Type Details) 
setting the value of Application.StatusBar
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Something truly impressive
If you want a great tool for keeping the user informed you should create a progress bar form, show the form before beginning code execution, and hide it afterwards. This is something you could do yourself, but to get you started, I've been employing and improving on my own custom progress bar for quite some time now. I think you should find it useful and very customizable:
 
Progress-Bar.PNG (10 KB) (File Type Details) 
Progress Bar
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Features
  • Programmer can configure the progress bar with one function call, then all that is needed to update is to call SetValue.
  • The progress bar's position and percentage label are automatically computed based on the minimum, maximum, and last set value.
  • The status (caption above the progress bar) can be set dynamically to indicate additional information, such as the current stage of execution.
  • An optional cancel button allows the user a mechanism to halt your lengthy process. The cancel button text can also be set, for instance to "Stop" or "Cancel Generation". The default caption is "Cancel". If set to vbNullString, the cancel button is hidden entirely.
  • An optional label can show the time elapsed since the dialogue box was configured. (It is assumed that you will configure the dialogue directly before showing it). If this option is disabled, the progress bar update routine will not waste time in computing the elapsed time.
  • An optional label can estimate the time remaining before completion. This is a very accurate estimate if you have appropriately set the min and max values. (You can test this in the example below.) This can be disabled, in which case no time is wasted in computing the remaining time.
  • Your calling routine can get the current value of the progress bar, as well as the formatted run time. I use this, for instance, for logging, or to display on the status bar the final run time of the routine after it is complete.
     
    Time-Taken.PNG (2 KB) (File Type Details) 
    Display the final runtime in the status bar
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Using the progress bar practically
You are responsible for picking an appropriate minimum and maximum value. For instance, if you are looping over R rows (from 1 to R) and C columns (from 1 to C), you should set the minimum to 0 and the maximum to ( R*C ). Furthermore, if you are currently on row i and column j, (and you are looping over all rows within each column), you should be setting the current value to [ i + (j-1)*R ]

If the cancel button is being displayed, you are responsible for periodically checking whether or not the cancel button has been pressed. Do this by checking whether ProgressDialogue.cancelIsPressed is true. If it is true, you should exit the loop and clean up after your routine. Ideally, we could avoid polling using events, but there is no sophisticated event hooking in VBA. An alternative would be to modify the progress dialogue CancelButton_Click method to work very specifically with what you are doing, but regularly checking cancelIsPressed() shouldn't take too much out of your routine's runtime.

The following code block shows the function calls you should remember to include in your loops when using the progress bar dialogue:
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Sub wasteTime()
    Dim i As Long
    Dim diag As New ProgressDialogue
    diag.Configure "Wasting Time", "Now wasting your time...", -10000, 10000
    diag.Show
    For i = -10000 To 10000
        diag.SetValue i
        diag.SetStatus "Now wasting your time... " & i
        If diag.cancelIsPressed Then Exit For
    Next i
    diag.Hide
End Sub


This produces the following progress bar:
 
Sample-Progress-Bar.PNG (9 KB) (File Type Details) 
Using All Features in a Simple Case
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If you are looping over code where you are making a large number of iterations over code that is very quick to execute, then you might find that updating the dialogue becomes your bottleneck. To prevent this, you can only update the progress bar periodically, using a quick check. For instance, you can say:
If index MOD 1000 = 0 Then ProgressDialogue.SetValue(index)
This way, the dialogue will only get updated every 1000 loops, and it will have much less impact on your code. You will want to play around with how often you update it, to balance the refresh rate with the amount of time spent updating the progress bar. Ideally, in other applications, a progress bar is kept up to date in a thread, but VBA has no support for threading.

Implemented Example and Code
Here, I've attached a workbook containing the 'wasting time' example above. You can use this to experiment with the ProgressDialogue form, and take a look at its implementation.
 
Progress-Bar-Example.xls (56 KB) (File Type Details) 
'Wasting Time' Example
 


For convenience, I've also included in this article the code within the ProgressDialogue class:
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Option Explicit 
Dim Cancelled As Boolean, showTime As Boolean, showTimeLeft As Boolean
Dim startTime As Long
Dim BarMin As Long, BarMax As Long, BarVal As Long  
 
Private Declare Function GetTickCount Lib "Kernel32" () As Long  
 
'Title will be the title of the dialogue.
'Status will be the label above the progress bar, and can be changed with SetStatus.
'Min is the progress bar minimum value, only set by calling configure.
'Max is the progress bar maximum value, only set by calling configure.
'CancelButtonText is the caption of the cancel button. If set to vbNullString, it is hidden.
'optShowTimeElapsed controls whether the progress bar computes and displays the time elapsed.
'optShowTimeRemaining controls whether the progress bar estimates and displays the time remaining.
'calling Configure sets the current value equal to Min.
'calling Configure resets the current run time.
Public Sub Configure(ByVal title As String, ByVal status As String, _
                     ByVal Min As Long, ByVal Max As Long, _
                     Optional ByVal CancelButtonText As String = "Cancel", _
                     Optional ByVal optShowTimeElapsed As Boolean = True, _
                     Optional ByVal optShowTimeRemaining As Boolean = True)
    Me.Caption = title
    lblStatus.Caption = status
    BarMin = Min
    BarMax = Max
    BarVal = Min
    CancelButton.Visible = Not CancelButtonText = vbNullString
    CancelButton.Caption = CancelButtonText
    startTime = GetTickCount
    showTime = optShowTimeElapsed
    showTimeLeft = optShowTimeRemaining
    lblRunTime.Caption = ""
    lblRemainingTime.Caption = ""
    Cancelled = False
End Sub  
 
'Set the label text above the status bar
Public Sub SetStatus(ByVal status As String)
    lblStatus.Caption = status
    DoEvents
End Sub  
 
'Set the value of the status bar, a long which is snapped to a value between Min and Max
Public Sub SetValue(ByVal value As Long)
    If value < BarMin Then value = BarMin
    If value > BarMax Then value = BarMax
    Dim progress As Double, runTime As Long
    BarVal = value
    progress = (BarVal - BarMin) / (BarMax - BarMin)
    ProgressBar.Width = 292 * progress
    lblPercent = Int(progress * 10000) / 100 & "%"
    runTime = GetRunTime()
    If showTime Then lblRunTime.Caption = "Time Elapsed: " & GetRunTimeString(runTime, True)
    If showTimeLeft And progress > 0 Then _
        lblRemainingTime.Caption = "Est. Time Left: " & GetRunTimeString(runTime * (1 - progress) / progress, False)
    DoEvents
End Sub  
 
'Get the time (in milliseconds) since the progress bar "Configure" routine was last called
Public Function GetRunTime() As Long
    GetRunTime = GetTickCount - startTime
End Function  
 
'Get the time (in hours, minutes, seconds) since "Configure" was last called
Public Function GetFormattedRunTime() As String
    GetFormattedRunTime = GetRunTimeString(GetTickCount - startTime)
End Function  
 
'Formats a time in milliseconds as hours, minutes, seconds.milliseconds
'Milliseconds are excluded if showMsecs is set to false
Private Function GetRunTimeString(ByVal runTime As Long, Optional ByVal showMsecs As Boolean = True) As String
    Dim msecs&, hrs&, mins&, secs#
    msecs = runTime
    hrs = Int(msecs / 3600000)
    mins = Int(msecs / 60000) - 60 * hrs
    secs = msecs / 1000 - 60 * (mins + 60 * hrs)
    GetRunTimeString = IIf(hrs > 0, hrs & " hours ", "") _
                     & IIf(mins > 0, mins & " minutes ", "") _
                     & IIf(secs > 0, IIf(showMsecs, secs, Int(secs + 0.5)) & " seconds", "")
End Function  
 
'Returns the current value of the progress bar
Public Function GetValue() As Long
    GetValue = BarVal
End Function  
 
'Returns whether or not the cancel button has been pressed.
'The ProgressDialogue must be polled regularily to detect whether cancel was pressed.
Public Function cancelIsPressed() As Boolean
    cancelIsPressed = Cancelled
End Function  
 
'Recalls that cancel was pressed so that they calling routine can be notified next time it asks.
Private Sub CancelButton_Click()
    Cancelled = True
    lblStatus.Caption = "Cancelled By User. Please Wait."
End Sub


Because .frm and .frx files cannot be attached on experts-exchange, I cannot provide you with those directly, but you can easily add this progress bar to any project by following these steps:
1. Download the example excel file above
2. Open the file, and open the VBA project (Alt+F11)
3. Export the ProgressDialogue form. (Save it somewhere you will remember in 5 seconds).
4. Import the exported file in any other excel project. (You can now delete the exported .frm and .frx files from your system.)
 
Export-and-Re-import.PNG (39 KB) (File Type Details) 
Step 3 and 4 of adding a progress bar
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Remember that this same concept can be adapted to other Microsoft Applications, Excel is simply where I've built it here.

Building pleasant user interfaces is crucial to the success and reception of your VBA applications and I think this progress bar dialogue can go a long way to improving that. Feel free to use these ideas and code, and build on them. I wish you success!

--
Alain Bryden


References
Progress bar with a user form in Excel - http://support.microsoft.com/kb/211736
GetTickCount system function in VBA - http://msdn.microsoft.com/en-us/library/aa537191%28office.11%29.aspx
 
Interfaced-Progress-Bar-Example.xls (74 KB) (File Type Details) 
Progress Bar using Interface Class