Hi List,
I want to run a development technique past the experts in the list to get
comments and suggestions:
We need to write a large and extensible application using WinForms. I have
worked out a design strategy but would appreciate any commentes from the
experts in the list. The idea I have in mind is to have a container program
coded as an EXE, based on an MDI form. This will not do any application
processing but will load and run the other programs. These will be coded as
single classes inheriting from System.Windows.Forms. A number of these
classes can be compiled into a single DLL assembly which can be put on an
Intranet web server. The code to load and run the form in the DLL is as
follows:
Dim ClassName As String ' Name of the class to be instantiated
Dim AssemblyFileName As String ' URL where we look for the
assembly
Dim AssemblyName As String ' Name of the Assembly
Dim Assem As System.Reflection.Assembly
Dim ProgObj As Object
Dim ProgType As Type
' For the sake of demonstration, set these values explicitly.
' In the real app they will be read in from a database
AssemblyFileName = "C:\VBDotNet\TestProject\bin\TestProject.dll"
AssemblyName = "TestProject"
ClassName = "MyForm" ' MyForm is a class in TestProject inherited
from Windows.Forms.Form
Assem = System.Reflection.Assembly.LoadFrom(AssemblyFileName) '
Load the assembly
ProgType = Assem.GetType(AssemblyName & "." & ClassName) '
Get the Type
ProgObj = Activator.CreateInstance(ProgType) '
Create an Instance
ProgObj.MDIParent = mvarMDIMain ' Put it in as a child
of the MDI form...
ProgObj.Show() ' ... and show!
I have found this to work, and it seems to have enormous possibilities:
- We can group logically related applications in the same DLL assembly
- We can easily implement new versions of apps by either overwriting the
DLL assembly or simply by changing the value of AssemblyFileName so the
program looks in a different place for the new version.
I am happy about other aspects of this development, e.g. passing data
between the loaded form and the container. What I really want a warm
feeling about is whether this use of System.Reflection is a viable way of
creating an extensible application, or whether I am storing up trouble for
myself further down the line. I await your gracious comments.
Regards,
Jay Ayliff
Stalis Ltd
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