Working with assemblies

[Max]

I made a class library which I want to load when something happens.
How can I load this library and then pass in a paramter?

I tried:

Assembly asm = Assembly.Load("mylibrary");
Type t = asm.GetType("MyClass");
Object obj = Activator.CreateInstance(t, new object[] {myargument});

and I get an exception:

Exception caught: System.ArgumentNullException: Value cannot be null.
Parameter name: type
at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[]
activationAttributes)
at System.Activator.CreateInstance(Type type, Object[] args)

 

[Nicholas Paldino [.NET/C# MVP]]

Max,

The reason you are getting this is that the type, t, is null. When you
make the call to GetType (on the Assembly instance asm), you need to pass
the namespace-qualified type name. Change the string to that, and it should
work.

Hope this helps.

 

[Max]

What is the namespace-qualified type name?
I changed the code to this and t is still null.

Assembly asm = Assembly.Load("mylibraryfile");
Type t = asm.GetType("mylibraryNamespace");
Object obj = Activator.CreateInstance(t, new object[] {myargument});

Max,

The reason you are getting this is that the type, t, is null. When you
make the call to GetType (on the Assembly instance asm), you need to pass
the namespace-qualified type name. Change the string to that, and it should
work.

Hope this helps.


--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

I made a class library which I want to load when something happens.
How can I load this library and then pass in a paramter?

I tried:

Assembly asm = Assembly.Load("mylibrary");
Type t = asm.GetType("MyClass");
Object obj = Activator.CreateInstance(t, new object[] {myargument});

and I get an exception:

Exception caught: System.ArgumentNullException: Value cannot be null.
Parameter name: type
at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr,
Binder binder, Object[] args, CultureInfo culture, Object[]
activationAttributes)
at System.Activator.CreateInstance(Type type, Object[] args)

 

[Willy Denoyette [MVP]]

I made a class library which I want to load when something happens.
How can I load this library and then pass in a paramter?

I tried:

Assembly asm = Assembly.Load("mylibrary");
Type t = asm.GetType("MyClass");
Object obj = Activator.CreateInstance(t, new object[] {myargument});

and I get an exception:

Exception caught: System.ArgumentNullException: Value cannot be null.
Parameter name: type
at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr,
Binder binder, Object[] args, CultureInfo culture, Object[]
activationAttributes)
at System.Activator.CreateInstance(Type type, Object[] args)

That means that t is null. Are you sure "MyClass" exists in "myLibary"?

Willy.

 

[Nicholas Paldino [.NET/C# MVP]]

Max,

You need the namespace and the type, like this:

Type t = asm.GetType("mylibrarynamespace.mytype");


--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

What is the namespace-qualified type name?
I changed the code to this and t is still null.

Assembly asm = Assembly.Load("mylibraryfile");
Type t = asm.GetType("mylibraryNamespace");
Object obj = Activator.CreateInstance(t, new object[] {myargument});

Max,

The reason you are getting this is that the type, t, is null. When
you make the call to GetType (on the Assembly instance asm), you need to
pass the namespace-qualified type name. Change the string to that, and
it should work.

Hope this helps.


--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

I made a class library which I want to load when something happens.
How can I load this library and then pass in a paramter?

I tried:

Assembly asm = Assembly.Load("mylibrary");
Type t = asm.GetType("MyClass");
Object obj = Activator.CreateInstance(t, new object[] {myargument});

and I get an exception:

Exception caught: System.ArgumentNullException: Value cannot be null.
Parameter name: type
at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr,
Binder binder, Object[] args, CultureInfo culture, Object[]
activationAttributes)
at System.Activator.CreateInstance(Type type, Object[] args)

 

[Max]

Yes the class exists.
Anyways I got it to work by getting all the Types and then getting the method I wanted...

I made a class library which I want to load when something happens.
How can I load this library and then pass in a paramter?

I tried:

Assembly asm = Assembly.Load("mylibrary");
Type t = asm.GetType("MyClass");
Object obj = Activator.CreateInstance(t, new object[] {myargument});

and I get an exception:

Exception caught: System.ArgumentNullException: Value cannot be null.
Parameter name: type
at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr,
Binder binder, Object[] args, CultureInfo culture, Object[]
activationAttributes)
at System.Activator.CreateInstance(Type type, Object[] args)

That means that t is null. Are you sure "MyClass" exists in "myLibary"?

Willy.