Making a DLL file
In this tutorial, we are going to make a simple calculator library that does addition, subtraction, multiplication, and division using C# in Visual Studio.
Create the project (library) in Visual Studio as follows
- Create new project
- Select C# Class Library (.Net Standard)
- Project name -> MyCalculator
The code for your library
Add the following code:
using System;
namespace MyCalculator
{
public class Calculator
{
//Our addition function
public double add(double num_one, double num_two)
{
return num_one + num_two;
}
//Our subtraction function
public double subtract(double num_one, double num_two)
{
return num_one - num_two;
}
//Our multiplication function
public double multiply(double num_one, double num_two)
{
return num_one * num_two;
}
//Our division function
public double divide(double num_one, double num_two)
{
return num_one / num_two;
}
}
}
Building your library project
Click on: Build -> Build Solution
Locating your Calculator Library
Your MyCalculator.dll is located in:
Your project folder -> MyCalculator -> MyCalculator -> bin -> debug
Using the DLL file in .Net
We are going to use our Calculator library MyCalculator.dll in a simple C# application.
Create a c# console application in Visual Studio as follows:
- File -> New -> Project
- Select: C# Console App
- Project name: MyProject
Importing our calculator library
- Copy
MyCalculator.dllfrom: Your library project folder -> MyCalculator -> MyCalculator -> bin -> debug - Paste
MyCalculator.dllto Your project folder -> MyProject -> MyProject -> bin -> debug - Add reference to your dll file: In solution explorer: Under MyProject -> Right click MyProject -> add -> Project reference
- Browse: Go to (Your project folder -> MyCalculator -> MyCalculator -> bin -> debug ->
MyCalculator.dll - Click add
The code for your project (MyProject)
Edit your code as follows:
using System;
using MyCalculator; // importing our calculator library
namespace MyProject
{
class Program
{
static void Main(string[] args)
{
Calculator calc = new Calculator(); //Our Acalculator class object
Console.WriteLine("Addition: "+calc.add(3, 2));
Console.WriteLine("Subtraction: " + calc.subtract(3, 2));
Console.WriteLine("Multiplication: " + calc.multiply(3, 2));
Console.WriteLine("Division: " + calc.divide(3, 2));
}
}
}
Using the DLL file in Python
Install pythonnet
pip install pythonnet
Python code
import clr #import clr from pythonnet
#load our dll file(mine is in my C: folder)
clr.AddReference("C:MyCalculator.dll")
#import our calculator class from Our C# namespace MyCalculator
from MyCalculator import Calculator
calc = Calculator() #create our Calculator object
#calling our methoths and printing
print("Addition: "+str(calc.add(3, 2)))
print("Subtraction: "+str(calc.subtract(3, 2)))
print("Multiplication: "+str(calc.multiply(3, 2)))
print("Division: "+str(calc.divide(3, 2)))