c# - How to use string as generic type

Question

This question already has answers here: question from:https://stackoverflow.com/questions/65877533/how-to-use-string-as-generic-type

Answer 1

Take a look at Type.GetType(string):

string name = GetClassName();

Type klass = Type.GetType("Namespace." + name); // Replace "Namespace." with all the namespaces the classes live in, as the argument to `Type.GetType()` should be a fully-qualified name
if (klass is null)
{
    // Class was not found
}

Of course, you also need to create an instance of Generic<klass>:

Type genericOfKlass = typeof(Generic<>).MakeGenericType(klass);

Then instantiate it:

object instance = Activator.CreateInstance(genericOfKlass);

Then call .DoSomething() on it:

MethodInfo doSomething = genericOfKlass.GetMethod("DoSomething", BindingFlags.Public | BindingFlags.Instance);
doSomething.Invoke(instance, new object[] { });

As you can see, reflection (this kind of dynamic programming is called reflection) is not easy, but possible in .NET.

Edit: Complete example with request data:

Request request = GetClientRequst();

//container is IContainer of Autofac.

Type requestType = Type.GetType("Namespace." + requestType); // Replace "Namespace." with all the namespaces the classes live in, as the argument to `Type.GetType()` should be a fully-qualified name
Type entityDao = typeof(EntityDao<>).MakeGenericType(requestType);
MethodInfo containerResolve = container.GetType().GetMethod("Resolve");
MethodInfo genericContainerResolve = containerResolve.MakeGenericMethod(entityDao);
object resolveResult = genericContainerResolve.Invoke(container, new object[] { });
MethodInfo create = resolveResult.GetType().GetMethod("Create");
create.Invoke(resolveResult, new object[] { request.Data });