Why "DisplayAlerts = False" Makes Access Queries Jump Into Debugging Mode
Have you ever tried to export data from an Access query using VBA and found yourself unexpectedly diving into debug mode? The culprit might be the infamous DisplayAlerts property. While seemingly simple, its interaction with export operations can lead to frustrating behavior, especially when set to False.
The Scenario:
Let's say you have a simple VBA function to export data from an Access query to a CSV file:
Sub ExportQueryToCSV()
Dim strFileName As String
Dim strQueryName As String
strFileName = "C:\MyData\Export.csv"
strQueryName = "MyQuery"
DoCmd.TransferText acExportDelim, , strFileName, strQueryName
End Sub
This code is designed to export the data from the query "MyQuery" to the specified CSV file. However, when DisplayAlerts is set to False in your Access application (typically in the AutoExec macro), this seemingly innocent export operation can trigger an unexpected jump into debug mode.
The Explanation:
The issue arises because Access has a built-in safety mechanism. When DisplayAlerts is set to False, Access is essentially told to suppress any warnings or prompts that might otherwise pop up during actions like exporting data. This can include warnings about potential data loss, overwriting existing files, or other potential issues.
However, Access still needs to check for these potential issues before executing the export. And when it encounters a scenario where it would normally display a warning (for example, if the target file already exists), it might trigger the "Step Into" debug mode instead of simply suppressing the alert.
The Solution:
There are two main ways to address this issue:
-
Enabling
DisplayAlerts: The simplest solution is to setDisplayAlertstoTruefor your export operation. While this will re-enable warnings, it allows you to be aware of potential issues and react accordingly. You can either change theDisplayAlertssetting in your VBA code temporarily before running the export, or revert to usingDoCmd.OutputTowhich allows forOutputFormatspecification and can accommodateacFormatCSV. -
Addressing the Warning: Instead of suppressing the warning altogether, you can identify the specific reason for the warning and handle it directly in your code. For instance, if the problem is a pre-existing target file, you can use the
FileExistsfunction to check before exporting and either delete the existing file or choose an alternative filename.
Examples:
1. Enabling DisplayAlerts:
Sub ExportQueryToCSV()
Dim strFileName As String
Dim strQueryName As String
strFileName = "C:\MyData\Export.csv"
strQueryName = "MyQuery"
DoCmd.SetWarnings True ' Temporarily enable DisplayAlerts
DoCmd.TransferText acExportDelim, , strFileName, strQueryName
DoCmd.SetWarnings False ' Revert to original setting
End Sub
2. Handling the Warning:
Sub ExportQueryToCSV()
Dim strFileName As String
Dim strQueryName As String
strFileName = "C:\MyData\Export.csv"
strQueryName = "MyQuery"
If Dir(strFileName, vbDirectory) <> "" Then ' Check if file exists
' Handle existing file: Delete, Rename, etc.
Else
DoCmd.TransferText acExportDelim, , strFileName, strQueryName
End If
End Sub
Conclusion:
Understanding the intricacies of the DisplayAlerts property and its impact on Access' export operations is crucial to avoiding unexpected debugging sessions. By either enabling warnings or proactively handling potential issues in your code, you can ensure a smoother and more predictable export process.
Remember: Always test your code thoroughly to prevent data loss or unexpected behavior.
References:
