C# – How to define a default constructor by code using StructureMap

Your code sample does not provide enough information. Are you configuring the container owned by ObjectFactory, or are you creating your own instance of Container? ObjectFactory can only access its own Container.

You are trying to call GetAllInstances on ObjectFactory, but you call WhatDoIHave on Container. It is not clear which container you are configuring with the "Scan" statement you included.

Using the code you provided (and assuming use of ObjectFactory throughout), I was not able to reproduce your issue. Make sure you are consistently using the same container.

If that doesn't solve your problem, you might consider posting to the StructureMap mailing list, where it will get a lot more attention from StructureMap users.

Unfortunately I have little familiarity with configuring StructureMap via Xml. Let me show you how it is done using C#.

var container = new Container(config=>
{
  config.For<ISysMsgRepository>().Use<SysMsgRepository>();
});

It seems you are using the standard naming convention for your interfaces and classes (just tacking an I onto the front of the class name). If you do that for all your types you can just configure your container like this:

var container = new Container(config=>
{
    config.Scan(scan =>
    {
        scan.TheCallingAssembly();
        scan.WithDefaultConventions();
    });
});

I hope this helps. It is much easier to configure your container using code rather than Xml. Give it a try. You'll be a convert.