ThreeWave Alerter Message Display Component

This page introduces the Alerter message display component
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Introduction

Frequently, a VBA application needs to display messages to the user, especially if you are the user and you are debugging some code. Using native Excel and VBA objects, you have three methods to display information:

  • MsgBox message boxes
  • Debug.Print statements
  • Application.StatusBar messages

Each of these has disadvantages. For example, a MsgBox requires that you click on it to continue running code. Having to click off a number of message boxes quickly becomes tiresome.  Debug statement show up only in the VBA editor, so you have to switch between Excel and VBA to see the messages. StatusBar messages are not very obvious and one message disappears as the next one is displayed.

The Alerter component overcomes these limitations. It is an ActiveX DLL, usable in any Office program, 97 or later, that displays a modeless form on which messages can be displayed. Since it is modeless, it can remain visible while your code executes.  Messages remain in the display as new messages are added, scrolling upwards. The Alerter screen is shown below:

Alerter Screen 

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Installation

Download the zip file to some directory, unzip the file, and run AlerterSetup.exe. This will install Alerter to the folder of your choice and register the component with Windows. You can download the Alerter Setup program here. You can download an example workbook here.

 

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Usage Instructions

Once you have installed Alerter, you need to set a reference to the DLL file from your VBA project. In the VBA editor, go to the Tools menu, choose References and scroll down to Alerter and check the box, as shown below.

AlerterReference  

With this reference in place, you can use the Alerter object and its methods.  First, declare a Public variable of the type Alert.Alerter and then set the properties. For example,

Public Alerter As Alert.Alerter

Sub InitializeAlerter()
    If Alerter Is Nothing Then
        Set Alerter = New Alert.Alerter
    End If
    With Alerter
        .SetParentWindow -1
        .Caption = "Alerts For Testing"
        .EnableEVents = True
        .FormVisible = True
        .MaxListCount = 100
        .MaxPriority = 100
        .MinPriority = 1
        .ShowCounter = True
    End With
End Sub

This will initialize the Alerter component. To display a message in the window, use code like the following:

Alerter.DoAlert AlertText:="This Is Some Test Code", Priority:=10

The Priority parameter is optional. See below for a description of all parameters, properties and methods.

 

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Alerter Properties, Methods, And Events

The following table describes the properties, methods, and events of the Alerter object.

Property Description
Caption This sets or returns the caption of the Alerter form. The default is "Alert Messages". Variable type: String.
Count This returns the number of messages in the Alerter list. Read-only. Variable type: Long
EnableEvents This sets or returns whether Alerter should raise its events to the containing class. Variable type: Boolean.
FormVisible This sets or returns whether the Alerter window is visible. Variable type: Boolean.
HWnd This returns the window handle of the main Alerter window. Read-only. Variable type: Long
LastMessage This returns the last (most recent) message in the Alerter window. Read-only. Variable type: String
Left This returns the left position of the Alerter window. Read-only. Variable type: Single
MaxListCount This sets or returns the maximum number of messages to display. When MaxListCount is reached, the earliest (top most) messages are deleted to make room for new messages. The default is 0, indicating no maximum. Variable type: Long
MaxPriority This sets or returns the maximum priority of messages that will be displayed in the list. If a message is sent with a Priority greater than MaxPriority, it will not be displayed. The values you use for the MinPriority and MaxPriority are entirely up to you. There is no default. The only restriction is the both the MinPriority and MaxPriority must be between 0 and 999999. Variable type: Long
MinPriority This sets or returns the minimum priority of messages that will be displayed in the list. If a message is sent with a Priority less than MinPriority, it will not be displayed. See MaxPriority.
ReturnFocus This sets or returns whether focus should return to the host application. The default value is True. Variable type: Boolean.
ShowCounter This sets or returns whether messages should be displayed with a counter in the list. The default value is False. Variable type: Boolean
ShowPriority This sets or returns whether the Priority should be displayed in the message list. The default value is False. Variable type: Boolean
Top This returns the Top position of the Alerter window. Read-only. Variable type: Single
Methods  
ClearList This clears the message list.
DeleteSelectedMessages
 This deletes messages selected in the list.
DoAlert This sends a message to the Alerter window. This method takes two parameters: AlertText (required String) is the text of the message to be displayed; Priority is the priority of the message (optional Long). If Priority is less than MinPriority or greater than MaxPriority, the message will not be displayed. The default priority is -1. 

ResetCounter This resets the message counter to zero.
SetLocation This positions the Alerter window on the screen. This takes two required parameters, Top and Left, both Single data types.
SetParentWindow This sets the parent window of the Alerter window. If this is numeric and less than or equal to zero, the Application's main window is used. If numeric and greater than zero, this is the HWnd of the window to become the parent of the Alerter window. If this is a string, it should be the Window Class of the new parent window (e.g., "XLMAIN").
Events  
AfterAlert Raised after an alert has been posted to the list.
AfterClear Raised after the message display has been cleared.
AfterPriorityChange Raised after either MinPriority or MaxPriority has been changed.
BeforeAlert Raised before an alert is posted to the list. Set Cancel to True to cancel the post operation.
BeforeClear Raised before the message list is cleared. Set Cancel to True to cancel the clear operation.
BeforeCounterReset Raised before the counter is reset to zero. Set Cancel to True to cancel the reset operation.
BeforeHide Raised before the Alerter window is hidden. Set Cancel to True to cancel the hide operation.
BeforePriorityChange Raised before the MinPriority or MaxPriority is changed. Set Cancel to True to cancel the change operation.
BeforeShow Raised before the window is made visible. Set Cancel to True to Cancel the show operation.
   

You can download the Alerter Setup program here. You can download an example workbook here.

If you are interested in the VB6 source code, email me.

This page last updated: 12-July-2007

 

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