实例化实现接口C＃的通用类型

Question

I have the following generic type:

public class CommandFlow<T> : IFlow where T: IFlow
{
    private T _flow;
    public CommandFlow(T flow)
    {
        _flow= flow;
    }    
}

where IFlow has some implementations: StaticFlow, DynamicFlow, CombinedFlow. I want to instantiate the generic type with Active.CreateInstance, so I have the code:

var flowType = typeof(CommandFlow<>).MakeGenericType(nominalFlowType);
//nominalFlowType is one of the types: StaticFlow, DynamicFlow, CombinedFlow

Then I try to instantiate the generic type:

var commandFlow = Activator.CreateInstance(flowType, new object[] {new StaticFlow()});

I get the error:

"Constructor on type 'CommandFlow`1[[DynamicFlow, ...]]' not found"

Answer 1

The error indicates that you are trying to construct an object of type CommandFlow<DynamicFlow> , so nominalFlowType must have been DynamicFlow .

As you're trying to pass a StaticFlow as a constructor argument, there isn't any constructor that can do this; you'd need to pass a DynamicFlow value.