Re: Twain inheritance

Hello,

I am using LeadTools v17. and the VB.NET class library.

It would be difficult to me to explain what I want to achieve but I will try it:

We are developing a .Net project for scanning images. As we do not want to add leadtools references to this project, we are also developing a class library proyect with leadtools references and some "custom" functions and properties. Then, we will add to the scanning project, a reference to our class library project.

So, I need some help to do this class library project. Making a class that inherits from TwainSession, how could I overload the AcquirePage event??? My purpose is something like this:

Our Class Library Project:

Imports Leadtools
Imports Leadtools.Twain

Public Class Digitalizador17
    Inherits TwainSession
.
.
.
.
.
.
End Class

Scanning Project

Imports Our Class Library Project namespace

Dim oDigitalizador as Digitalizador17
.
.
.
.
 AddHandler oDigitalizador."Our Event", AddressOf  "Any function"


So, in the Scanning project we cannot make a function with this signature :
(ByVal sender As Object, ByVal e As TwainAcquirePageEventArgs)
because we do not want to have the leadtools references on it.


I hope you could understand what we want to do.

Thanks very much,

Pablo L.G.

Pablo,
If you want to use any data type (such as TwainAcquirePageEventArgs) or enumeration defined in a Leadtools assembly, you must add a reference to that Leadtools assembly in the project that will use the data type. This is a .NET rule and not something specific to our toolkit.

Also, creating a project that uses a User ClassLibrary that uses Leadtools is allowed by our toolkit license agreement, but on the condition that every programmer who uses this User ClassLibrary must have a toolkit license seat.

This means if your User ClassLibrary will be used by 4 programmers (for example), you must own 4 copies of LEADTOOLS, and each of them must install our toolkit on his or her computer.

Furthermore, when you build an EXE that uses the User ClassLibrary, this EXE must be made to 'see' both your library DLL and the LEADTOOLS DLLs. The easiest way to do that is to copy your DLL and our toolkit files to the same folder that has the EXE, which can be done by adding references to the EXE project.

This means I suggest you do the following:
1. Do not create your own Class Library to wrap LEADTOOLS in it. Instead, add Leadtools references to your EXE project and use our classes directly in that project.
2. If you must create your own class library, add Leadtools references to your library and also add Leadtools references to your EXE project.

Understood :) Thanks very much Basel.