NetLegacySupport

Library helps supporting old .NET frameworks like .NET 2.0 and 3.5. This is a backport from .NET Core. Following classes are provided:

• System.Action
• System.Tuple
• System.Collections.Concurrent.ConcurrentDictionary

System.Action

Action and Func is quite tricky to use in a multi target framework project because 2.0, 3.0 and 3.5 framework just provided subset of them.

• .NET Framework 2.0, 3.0 supports only Action<T>
• .NET Framework 3.5 supports Action, Func has up to 4 parameters.
• .NET Framework 4.0 supports Action, Func has up to 16 parameters.

To deal with this problem, this library provides missing classes in target framework.

Where can I get it?

PM> Install-Package NetLegacySupport.Action

Code that you can write.

Func<int, int, int, int, long> f =
    (a, b, c, d) => { return (long)a + b + c + d; };
Console.WriteLine(f(1, 2, 3, 4)); // 10

System.Tuple

Until .NET Framework 4, tuple was not supported. But it's an essential class that makes your code terse.

Where can I get it?

PM> Install-Package NetLegacySupport.Tuple

Code that you can write.

Tuple<int, string> t = Tuple.Create(1, "One");
Console.WriteLine(t); // (1, "One")

ConcurrentDictionary

ConcurrentDictionary is quite useful dictionary with a thread-safe feature. If your project is targeted toward .NET 3.5 only, Task Parallel Library for .NET 3.5 can be an option.

Where can I get it?

PM> Install-Package NetLegacySupport.ConcurrentDictionary

Code that you can write.

// New instance. (from http://www.dotnetperls.com/concurrentdictionary)
var con = new ConcurrentDictionary<string, int>();
con.TryAdd("cat", 1);
con.TryAdd("dog", 2);

// Try to update if value is 4 (this fails).
con.TryUpdate("cat", 200, 4);

// Try to update if value is 1 (this works).
con.TryUpdate("cat", 100, 1);

// Write new value.
Console.WriteLine(con["cat"]);