This article will show how to create a DLL file in .NET framework using Visual Studio.

Creating a dll file

To create a DLL follow the below steps

Open 'Visual Studio' and select File -> Open -> New ->Project

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Click on OK Button. Once you click on Ok 'Button' your Class Library looks as
follows.

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Now you can add whatever code that you need to. Here I have String as the return data type for the function. I will use this function in another project (.aspx) and show the Result in a TextBox.

namespace MyClassLibraryConsole
{
public class Class1
{
public string strfunction(string input)
{
string strmessage = input;
return strmessage;
}
}
}

Now you have to call this function in another project. Add New (or) Existing Project to your Solution. Here I am adding Existing .asp WebPages to my solution as follows.

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Once you have added your New or Existing Project your Solution will looks as follows.

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Adding created dll file in Solution Explorer:

Right click on DllDemo(.asp) solution and click on the select 'Add Reference'.

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Now you can find dialog Box. Select 3rd tab 'Projects'. Now can find your created ClassLibrary (dll) as 'MyClassLibraryconsole'.Select it and click 'OK' button.

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Now your dll is added successfully to your website. You can see your added dll in solution Explorer.

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Calling dll file function in .aspx.cs page:

protected void Button1_Click(object sender, EventArgs e)
{
MyClassLibraryConsole.Class1 obj = new MyClassLibraryConsole.Class1();
TextBox1.Text = obj.strfunction("Hellow World");
}

Showing the Result in TextBox:

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Thanks for Reading my Article!

Shakeer