---
title: "Creating C# Class Library (DLL) Using Visual Studio .NET"
description: "Creating C# Class Library in Visual Studio .NET is an easy way. Here I have described, How to create DLL in Visual Studio and"
author: "AVADHESH PATEL"
published: 2012-08-16
updated: 2020-07-24
canonical: https://www.mindstick.com/articles/980/creating-c-sharp-class-library-dll-using-visual-studio-dot-net
category: ".net"
tags: [".net"]
reading_time: 2 minutes
---
# Creating C# Class Library (DLL) Using Visual Studio .NET
## Creating C# Class Library (DLL) Using Visual Studio .NET
First of all, Creating C# [Class Library](https://www.mindstick.com/forum/158577/what-is-the-significance-of-the-base-class-library-bcl-in-the-dot-net-framework) in Visual Studio .NET is an easy way. Here I have described, How to create DLL in [Visual Studio and](https://www.mindstick.com/articles/618/create-microsoft-word-document-by-using-c-sharp) How to access this DLL in our project. Here I used Visual Studio 2010.\
##### Steps for Creating DLL
**Step 1:-** **File->New->Project->Visual [C# Projects](https://answers.mindstick.com/qa/93921/what-are-the-uses-of-partial-class-and-methods-in-c-sharp-and-why-are-use-in-c-sharp-projects)->Class Library.** Select [your project](https://www.mindstick.com/forum/156583/best-way-to-link-bootstrap-file-in-your-project) name and appropriate directory click OK
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After Clicking on button ‘OK’, solution explorer adds one C# class ‘Class1.cs’. In this class, we can write our code.
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When we [double click](https://www.mindstick.com/forum/156225/differentiate-between-google-adword-and-double-click) on Class1.cs, we see a [namespace](https://www.mindstick.com/articles/28/namespace-in-dot-net) CreatingDLL. We will be using this namespace in our project to access this class library.
**Step 2:-** Within Class1.cs we create a method named ‘sum’ that takes two integers value and returns the sum to which method passed numbers.
```
using System;namespace CreatingDLL{ public class Class1 { /// /// sum is method that take two integer value and return that sum /// /// /// /// public int sum(int x, int y) { return x + y; } }}
```
**Step 3:-** Now build the Application and see the bin\debug directory of our project. ‘CreatingDLL.dll’ is created. Now we create another application and take this DLL (CreatingDLL.dll) reference for accessing DLL’s method.
##### Steps for Accessing Created DLL
**Step 4:-** File->New->Project->Visual C# Projects->Windows [Form Application](https://www.mindstick.com/forum/34200/system-data-sqlclient-sqlexception-occurred-while-using-checked-or-radio-button-in-form-application).
**Step 5:-** Designed windows form as a bellow figure.
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**Step 6:-** [Add reference](https://www.mindstick.com/forum/548/how-to-add-reference-to-system-web-optimization) of DLL (CreatingDLL) which we created before few minutes.
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After adding reference of DLL, following windows will appear.
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**Step 7:-** Write code on [button click](https://www.mindstick.com/forum/568/check-condion-before-post-page-on-button-click-in-jquery-or-javascript) of Windows Form Application. Before creating an object and making the method of Add DLL, add namespace CreatedDLL in the project as bellow code.
```
using System;using System.Windows.Forms;using CreatingDLL;namespace AccessingDLL{ public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void btnAdd_Click(object sender, EventArgs e) { Class1 c1 = new Class1(); try { txtResult.Text
= Convert.ToString(c1.sum(Convert.ToInt32(txtNumber1.Text), Convert.ToInt32(txtNumber2.Text))); } catch(Exception ex) { MessageBox.Show(ex.Message); } } }}
```
**Step 8:-** Now build the application and execute the project and see the output.
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---
Original Source: https://www.mindstick.com/articles/980/creating-c-sharp-class-library-dll-using-visual-studio-dot-net
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