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Home » Newsletter » May 2015

By Ramnish R

In March this year, we released a version of XtremeDocumentStudio Delphi that added the ability to display data-aware form fields on the VCL document viewer control. Two new properties have been introduced to make this possible - FieldDataSource and FieldMapping. You need to first connect FieldDataSource to a data source on your computer. Then, you need to use FieldMapping to map the names of the form fields in the PDF document to column names in the data source.

public property FieldDataSource: TDataSource;
public function FieldMapping(FieldName: string): TgtFieldDataLink; virtual;

public: __property TDataSource FieldDataSource;
public: virtual __fastcall TgtFieldDataLink FieldMapping(AnsiString FieldName);

In the TgtFieldDataLink type, you will be mostly interested in DataFieldName and ValueMappings properties. The former is for identifying the form field. The latter is a name-value pair that is used to set the value of the form field in the document and the actual value that is submitted when the former gets chosen by the end-user or code.

public property DataFieldName: string;
public property ValueMappings: TDictionary;

public: __property AnsiString DataFieldName;
public: __property TDictionary ValueMappings;

Here is an example of using this new feature.

1. Start your IDE and open a new VCL Forms Application project.
2. Drop the following components on the form.
   • TDBGrid
   • TDataSource
   • TgtDocumentViewer
   • TButton (2)
   The TDataSource needs to be linked to a data set object. For simplicity, I have used a TADODataSet to load values from an Access database (NorthWind). You can choose some other component for your data source.
   
3. Set up your dataset properly so that it displays data in the grid at design-time.
4. In the first button "click" event handler, set the data source of the viewer and map the form field in the document to column names in the data source. Then, load the document containing the form fields.

   gtDocumentViewer1.FieldDataSource := DataSource1;
   gtDocumentViewer1.FieldMapping('f1_1[0]').DataFieldName := 'FirstName';
   
   gtDocumentViewer1.LoadFromFile(
     'C:\Users\egg\Documents\Gnostice\XtremeDocumentStudio Delphi'+
     '\Demos\Delphi\VCL\7. Document Viewer - Data aware Interactive forms'+
     '\Sample_tax_form.pdf');
   

   
5. Set the second button's "click" event handler to save the PDF form with the values from the selected record on the DB grid.

   gtDocumentViewer1.SaveToFile('Sample_tax_form_MODIFIED.pdf');
   

6. Run the project, click the first button, select a record and click the second button to save the values from the record to the PDF.
   

Of course, this example does not exactly map the form fields to columns in the database. For that, you will need to create a specialized database "view" and then display it in the grid.