T MyMethod<T>(T param)

Context: A generic method can take a parameter of the generic type and return a value of the same type. This ensures that input and output types are consistent without losing type information.

Usage Example

using System;

public class Manipulator
{
    public T Duplicate<T>(T original)
    {
        // For reference types, returns the same reference (simplified example)
        return original;
    }

    public T Convert<T>(object value)
    {
        return (T)Convert.ChangeType(value, typeof(T));
    }
}

class Program
{
    static void Main()
    {
        var manip = new Manipulator();
        int number = manip.Duplicate(100);
        Console.WriteLine(number);

        double decimalConverted = manip.Convert<double>("123.45");
        Console.WriteLine(decimalConverted);
    }
}

Output console

dotnet run
100
123.45

Important notes

• The type parameter T can appear as return type and as parameter type.
• This avoids explicit casts and improves type safety.

Real-world usage example

JsonSerializer.Deserialize<T>(string json) – Takes a type parameter T and returns an instance of T.
See .NET docs on JSON deserialization.

Related sections

• 11.2 Generic methods
• 11.2.2 Type inference