Why am I getting error CS0246: The type or namespace name could not be found?

Question

I am using Snarl C# API to send notifications to snarl.

Now I have saved the content of above url in a file named SnarlNetwork.cs and the content of my test.cs file are:

using SnarlNetworkProtocol; using System; class test {     public static void Main(String[] args)     {         SNP snarl_object = new SNP();         string hostname = "localhost";         string hostport = "9887";         string appName = "Spotify";          bool val = snarl_object.register(hostname, hostport, appName);          if (val == true)         {             string title = "hello";             string message = "world";             string timeout = "5";             bool newval = snarl_object.notify(hostname, hostport, appName, null, title, message, timeout);              if (newval == true)             {                 Console.WriteLine("sucessfull");              }         }     }  } 

Now when I try to compile my test.cs file using csc test.cs I get the following error:

C:\Users\Noob\csharp>csc test.cs Microsoft (R) Visual C# 2008 Compiler version 3.5.30729.4926 for Microsoft (R) .NET Framework version 3.5 Copyright (C) Microsoft Corporation. All rights reserved.  test.cs(1,7): error CS0246: The type or namespace name 'SnarlNetworkProtocol' could not be found (are you missing a using directive or an assembly reference?) 

So, what am I doing wrong here because according to me I am not missing any using directive.

Answer 1

I was using .NET Framework 4.5 but my new library had .NET Framework 4.5.2 and I got the same issue when I tried to build. I solved it by updating my project from 4.5 to 4.5.2 (same as my library).

Answer 2

1. On the Solution Explorer tab right click and select Properties

2. Resolve this issue by updating the Target Framework in the project application settings.

For instance, In my case the project was compiling with .net framework version 4.5.1 but the dll which were referenced were compiled with the version 4.6.1. So have updated the my project version. I hope it works for you.