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CHAPTER 5 Enhancing DataWindow Objects
DataWindow Designer User’s Guide 187
What happens at runtime
Data stored in a DataWindow object is stored within the actual object itself, so
when a window opens showing such a DataWindow, the data is already there.
There is no need to issue
Retrieve to get the data.
DataWindow .NET never retrieves data into a drop-down DataWindow that
already contains data. For all other DataWindow objects, if you retrieve data
into a DataWindow object stored with data, DataWindow .NET handles it the
same as a DataWindow object that is not stored with data: DataWindow .NET
gets the latest data by retrieving rows from the database.
Retrieving data
In a DataWindow object, you can prompt for retrieval criteria, retrieve rows as
needed, and save retrieved rows to disk.
Prompting for retrieval criteria in a DataWindow object
You can define your DataWindow object so that it always prompts for retrieval
criteria just before it retrieves data.
❖ To prompt for retrieval criteria in a DataWindow object:
1 If the Column Specifications view is not already displayed, select
View>Column Specifications from the menu bar.
In the default layout for the DataWindow painter, the Column
Specifications view displays in a stacked pane under the Properties view.
All columns defined for the DataWindow object are listed in the view.
2 Select the Prompt check box next to each column for which you want to
specify retrieval criteria at runtime.
When you specify prompting for criteria, DataWindow Designer displays the
Specify Retrieval dialog box just before a retrieval is to be done.
Each column you selected in the Column Specification view displays in the
grid. Users can specify criteria here exactly as in the grid in the Quick Select
dialog box. Criteria specified here are added to the
WHERE clause for the SQL
SELECT statement defined for the DataWindow object.