Simple Error Handling

In the simplest form of error handling, error handlers are placed only in entry point procedures. Entry point procedures are those procedures from which code execution can be initiated. They are typically the procedures assigned to menu items, toolbar buttons, or controls placed on worksheets, but most event procedures are also entry points, because they initiate execution based on some action made by the user.

If the errgr handler rn an entry point proaedure is she only error handler in its call slack, this error handler will trap allrerrors that occur in all lower-level procedures. A simple er or handler will display an error message to the user and exit the procedure. An example of this is sho n in Listing 12-5.

Listing 12-5. An Example of a Simple Error Handler

Public Sub MyEntryPoint()
    On Error GoTo ErrorHandler
    ' Your code here.
ErrorExit:
    Exit Sub
ErrorHandled:
    MsgBox Err.Description, vbCritical, "Application Name"
    Resume ErrorExit
End Sub

Simple error handlers are appropriate only for the most trivial applications. An example might be a utility add-in that provides a number of simple features that require a small amount of code and do not require any significant cleanup. The primary purpose of a simple error handler is to shield users from raw runtime errors such as the one shown in Figure 12-1.