使用Activator.CreateInstance创建类的实例并将Interface注入构造函数

Question

My goal is to create an instance of a class from it's AssemblyQualifiedName. The problem is that this class requires an interface to be passed in it's constructor and I am having trouble doing this with Activator.CreateInstance.

Thanks in advance for the help.

Once i have the AssemblyQualifiedName of the class I want to instantiate I got it's type using Type.GetType(AQN), used that type to find the constructor and get the required parameters.

I get stuck when calling Activator.CreateInstance and passing the parameters.

var objectType = Type.GetType(AQN);

var constructors = objectType.GetConstructors();

foreach (ConstructorInfo constructor in constructors)
{
    var parameters = constructor.GetParameters();                   
    var instantiatedObj = Activator.CreateInstance(objectType,parameters);
}

Once I do this i get the error "Constructor on Type xxx not found."

Answer 1

There's a Activator.CreateInstance that simply takes the type and the parameters to pass. So you can just say:

ISomeInterface something = null;

var objectType = Type.GetType(AQN);
var instance = Activator.CreateInstance(objectType, something);

Answer 2

if you want to create an instance of the class dynamically then you can do it like this too

        Type type = Type.GetType(AQN);
        PropertyInfo[] properties = type.GetProperties();
        var instance = (BaseClass)Activator.CreateInstance(type);

        for (int i = 0; i < properties.Length; i++)
        {
            PropertyInfo propertyInfo = type.GetProperty(properties[i].Name);
            var propertyVal = Convert.ChangeType(yourpropertyvalue,  
                             properties[i].PropertyType);
            propertyInfo.SetValue(instance, propertyVal);
        }
        return instance;