PDFlib 8 Windows COM/.NET Tutorial

eference calls for an int type argument, Visual Basic programmers should translate this
to long (although VB will correctly translate if int values are supplied).
A Visual Basic program can detect when an error happens, and react upon the error.
Catching Exceptions in Visual Basic is achieved with an On Error GoTo clause:
Sub main()
Dim oPDF As PDFlib_com.PDF
On Error GoTo ErrExit
...some PDFlib instructions...
End
ErrExit:
MsgBox Hex(Err.Number) & ": " & Err.Description
End Sub
Using the PDFlib COM edition with .NET. As an alternative to the PDFlib.NET edition
(see Section 2.7, ».NET Binding«, page 44) the COM edition of PDFlib can also be used
with .NET. First, you must create a .NET assembly from the PDFlib COM edition using the
tlbimp.exe utility:
tlbimp pdflib_com.dll /namespace:pdflib_com /out:Interop.pdflib_com.dll
You can use this assembly within your .NET application. If you add a reference to pdflib_
com.dll from within Visual Studio .NET an assembly will be created automatically.
The following code fragment shows how to use the PDFlib COM edition with VB.NET:
Imports PDFlib_com
...
Dim p As PDFlib_com.IPDF
...
p = New PDF()
...
buf = p.get_buffer()
The following code fragment shows how to use the PDFlib COM edition with C#:
using PDFlib_com;
...
static PDFlib_com.IPDF p;
...
p = New PDF();
...
buf = (byte[])p.get_buffer();
The rest of your code works as with the .NET version of PDFlib. Note that in C# you have
to cast the result of get_buffer( ) since there is no automatic conversion from the VARI-
ANT data type returned by the COM object here (similar casts are necessary for create_
pfv( )).
2.3 COM Binding 33