How Filter Criteria is Set
One of the benefits of this sample application is that the code can return an element and its contents from any XML document. To achieve this, the Command1_Click() procedure contains a statement that calls the SetFilterCriteria method in the ContentHandlerImpl class and passes it the value of the Text3 text box, as shown in the following code.
cnth.SetFilterCriteria (Text3.Text)
The following shows the SetFilterCriteria method in the ContentHandlerImpl class. The FilterCriteria variable is declared in the general section of the ContentHandlerImpl class.
Public Sub SetFilterCriteria(elementname)
FilterCriteria = elementname
End Sub
The value of the FilterCriteria variable is then tested in the startElement method in the ContentHandlerImpl class to determine if the specified element is within scope. The code to test FilterCriteria in the ContentHandler methods, along with a full code listing for the ContentHandlerImpl class, is included in the following topic.