NBuilder Usage On Collection

Question

I found this implementation of NBuilder here: https://gist.github.com/markgibaud/4150878

This works like a charm until I need to add some collection inside.
For example:

public class UserDto
{
    public string UserName {get;set;}
    public List<AddressDto> Addresses {get;set;} //this will be null
}

public class AddressDto
{
    public string Street {get;set;}
    //...
}

I want to fill any collection with at least one record.

I end up with this piece of code:

private static object BuildObjectList(Type type)
    {
        try
        {
            var builderClassType = typeof (Builder<>);
            Type[] args = {type};
            var genericBuilderType = builderClassType.MakeGenericType(args);
            var builder = Activator.CreateInstance(genericBuilderType);

            var createListOfSizeMethodInfo = builder.GetType().GetMethod("CreateListOfSize", new[] {typeof (int)});

            var objectBuilder = createListOfSizeMethodInfo.Invoke(builder, new object[] {1});
            var buildMethodInfo = objectBuilder.GetType().GetMethod("Build");
            return buildMethodInfo.Invoke(objectBuilder, null);
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex);
            return null;
        }
    }

But there's some issue also when I try to invoke build method.

Your code is right and returns a List of types that are passed. I think your problems stems from how you try to assigne the result of this method. Please add information on how you use it. — samy, Oct 15 '14 at 11:26
ShP, could you add the minimal code that reproduces the problem to your question, and add the error you encounter as well? — samy, Oct 15 '14 at 13:45
Sure, here's the exception: http://prntscr.com/4we88w This is the call: if (type.GetInterface("ICollection") != null) { baseType = BuildObjectList(type); } I get exception at this line: return buildMethodInfo.Invoke(objectBuilder, null); — ShP, Oct 15 '14 at 13:49
Please edit your question with the info you just gave, and also please add the type you're trying to create a list of. — samy, Oct 15 '14 at 13:53

Evil Dog Pie · Answer 1 · 2014-10-20T10:24:28.100

It looks like the Build method you are trying to invoke requires parameters, but you're not passing it anything when you call buildMethodInfo.Invoke(objectBuilder, null);

The exception being thrown is TargetParameterCountException. From MSDN:

The exception that is thrown when the number of parameters for an invocation does not match the number expected.

You should step through the code using the debugger and inspect the prototype of the method that is being invoked to see what parameters it takes. Considering your comment that the same issue is seen when the Build method is called in different ways (with no parameters passed to it), the implication is that the implementation of this method requires one or more parameters.

Alternatively, you could try calling the method statically, rather than through reflection, just to make sure that it can be called in the way the Invoke is calling it.

This case also failed: Builder>.CreateListOfSize(1).Build() ...and this one: Builder.CreateNew().Build() — ShP, Oct 17 '14 at 14:11

NBuilder Usage On Collection

1 Answers1