Part 5: Automating an Access Application in .NET framework

Encode Code 128 Code Set B in .NET framework Part 5: Automating an Access Application

User exits a control 5 (control BeforeUpdate and AfterUpdate events) ... User saves record 6 (form BeforeUpdate and AfterUpdate events) ...

Now that you understand events, it s useful to study the macro actions available to respond to events. Microsoft Access provides 56 macro actions. You can find these actions organized in the following functional categories:

Opening and closing Access objects tables, queries, forms, reports, data access pages, Printing data Executing a query Testing conditions and controlling action flow Setting values Searching for data Building a custom menu and executing menu commands Controlling display and focus Informing the user of actions Renaming, copying, deleting, saving, importing, and exporting objects Running another application

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and objects in an Access project file (.adp extension)

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Do I really recommend macros No, I don t! Although macros are a good way to learn to build simple automation in an Access application, they don t work well for a production application. First, as you ll see later in this chapter, the debugging facilities are very limited. If you run into any problem in your macro code, it can be very difficult to figure out the solution. Second, you cannot trap any errors in macros. In many cases, you cannot avoid errors. For example, if you attempt to GoToRecord Previous when you re on the first record, you ll get an error. Writing a test to detect that the form is already displaying the first record is difficult in a macro. If you use Visual Basic, you can trap the error and respond appropriately (ignore it!) without the user ever seeing the error. So, why am I teaching you macro actions In truth, the best (and perhaps only) way to perform certain actions in Visual Basic is to execute the equivalent macro action. For example, the only way to open a form that does not have any Visual Basic code is to execute the OpenForm action from within your Visual Basic procedure. (When a form has a module, an advanced way to open one or more copies of a form is to set a module object to the form s module.) As you ll learn in the next chapter, you execute macro actions in Visual Basic as methods of a special object called DoCmd. (In the following tables, I ll note the macro actions that have a better native equivalent in Visual Basic.)

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Closes either the specified window or, if no window is specified, the active window for a table, query, form, or report. If the Database window has the focus when you execute a Close action with no window specified, Access closes the database. You can also indicate whether to save the object when Access closes it. Opens a data access page in Browse (Page) or Design view. In an Access project file (.adp) connected to an SQL Server database, opens a table relationship diagram in the server database in Design view. You cannot execute this action in an Access desktop database (.mdb).

Opens a form in Form, Design, Datasheet, PivotTable, or PivotForm view or in Print Preview. You can also apply a filter or a Where condition in Form, Datasheet, PivotTable, or PivotForm view or in Print Preview. Access ignores any filter or Where condition when you open the object in Design view. If the form is already open, the OpenForm action puts the focus on the form and applies any new filter or Where condition you specify. From a Visual Basic procedure, you normally execute the macro action to open a form. However, you can also open a form that has a module by setting a form object equal to a new instance of the form s class module. See 22, Understanding Visual Basic Fundamentals, for details. In an Access project file (.adp) connected to an SQL Server database, opens a function in the server database in Datasheet, Design, PivotTable, or PivotChart view or in Print Preview. If the function is a data definition command or the equivalent of an Access action query, executes the function without returning data. If the function returns data that is editable, you can specify whether the function datasheet should be opened to add new records only; to add, edit, and delete records; or to provide a read-only view of the data. In Visual Basic, you can also use the Open or Execute method to open the function and return any results to a recordset. You must use the OpenFunction macro action within a Visual Basic procedure if you want the function to open in the user interface. You cannot execute this action in an Access desktop database (.mdb).