You will need to add your dllSource.dll to the
of your other project.
In the code for that project include a line
Now you can use the class in your dll like any other class or type. E.g.
private void button1_Click(object sender, EventArgs e)
Operation o = new Operation();
int i = o.Add(5, 10);
To get the parameter type(s) and return type ...
A) Manually - Right-click on the dllSource in the References section of Solution Explorer and select "View in Object Browser"
B) Whilst typing code - using my code above as an example type
and allow the intellisense to display then hover your mouse over the function you want the information on.
C) Programmatically - Use Reflection - have a look at this article
[Edit] prompted by comment below ... you will need to declare the class and function as
for any of the above to work