C#•2y ago

✅ Using Activator.CreateInstance() when the constructor has arguments - not finding constructor

I'm trying to create a class instance dynamically using Activator.CreateInstance(), and it's crashing and not finding the constructor. My object looks like this:

public class MyClass : MyBaseClass
{
    MyClass(ILogger logger) : base(logger)
    {}
}

public class MyClass : MyBaseClass
{
    MyClass(ILogger logger) : base(logger)
    {}
}

And I'm creating it like this:

Type myClassType = typeof(MyClass);
LoggerFactory loggerFactory = new();
ILogger logger = loggerFactory.CreateLogger(myClassType);
MyBaseClass? myInstance = (MyBaseClass?)Activator.CreateInstance(myClassType, logger);

Type myClassType = typeof(MyClass);
LoggerFactory loggerFactory = new();
ILogger logger = loggerFactory.CreateLogger(myClassType);
MyBaseClass? myInstance = (MyBaseClass?)Activator.CreateInstance(myClassType, logger);

However, when it hits the CreateInstance() line, an exception occurs:

An exception of type 'System.MissingMethodException' occurred in System.Private.CoreLib.dll but was not handled in user code: 'Constructor on type 'MyClass' not found.'

An exception of type 'System.MissingMethodException' occurred in System.Private.CoreLib.dll but was not handled in user code: 'Constructor on type 'MyClass' not found.'

Any idea what I'm doing wrong here?

5 Replies

Anton•2y ago

it doesn't call private constructors by default it needs an extra parameter

HughOP•2y ago

It should be a public constructor that's available to it, and I'm passing the logger in as a second parameter to CreateInstance()

Anton•2y ago

it's literally private in the code above

HughOP•2y ago

oh, sorry - that's my mistake when typing up the code in this question let me check my actual code too Ah shit, yes - it's private in my actual code Thanks - silly mistake! 🤦‍♂️

Anton•2y ago

Gaming

Programming

✅ Using Activator.CreateInstance() when the constructor has arguments - not finding constructor