DataGate Print Files
A DataGate Printer File is composed of one or more record formats, each defining a template of what is to be shown in a segment of the page. A record format is a collection of fields. In DataGate Classic, each field was embodied by an OLE ActiveX. One of the main enhancements of the new print files is the use of .NET controls to embody fields within records. These are the other major differences:
- XML representation of file definition.
- Conditional attributes at the file, format and field level with the ability to provide an array of Booleans to control condition attributes.
- Capability to direct the output to a text file where the data is formatted in XML instead of being printed.
- Capability to provide alternate render engines to print output on a fast text-based printer.
The following diagram shows the processes of editing, printing, and rendering print files and their output.
Editing
DataGate provides an editor (Print File Designer) to facilitate the creation and editing of print files. The editor is hosted inside Visual Studio and operates very similarly to the Forms Designer. With the editor, a developer can create new files and record formats. A record format gets populated with fields taken from the tool palette where the developer will find DataGate-provided controls and third-party controls installed on the machine.
An alternate way of editing a print file is to request the XML description from DataGate and manipulate it directly via normal XML processing. Afterwards, a new print file can be created using the new XML description.
Printing
The user program issues operations against the print file to create a
report. After connecting to the database, the program opens the print
file. As the program executes, multiple WRITE operations against
different record formats are made. Additionally, the control property
values might be set. The write operations cause DataGate to record the
values of fields and properties in a manuscript.
The manuscript is an XML document composed of four sections:
- Schema
- References
- Initial property values
- Document pages
The Schema defines the data fields found in the document pages. The References lists the assembly details of the third party controls used in the print file. The third section lists the initial values of the properties of all controls. These values are equivalent to the design-time settings selected when the file got create. Finally, the actual data generated by the user program is recorded as a group of pages in the last section. Each page is composed of one or more sections defining an area of the page to be printed.
When the print file is opened, it is possible to provide an actual location where to store the manuscript. If no location is provided, it is left to DataGate to determine whether to create the manuscript in a default disk location or to keep it in memory.
Rendering
The final phase in the process of creating a printout is the rendering of the manuscript. DataGate provides a default Renderer which yields a printout in the image of the original print file definition produced to a system installed printer. It is possible to use alternate renderers which can process the manuscript in arbitrary ways. For instance it is possible to use a product like Crystal Reports to create a printout from the data in the manuscript. There is also the possibility of using the manuscript as input to a process which 'grabs' the data from the report much like traditional report 'scrapping'.