// C# Extension Method

// Doc: https://csharp-extension.com/en/method/1002535/object-tonullableuint64ordefault

​

// @nuget: Z.ExtensionMethods

​

using System;

public class Program

{

    public static void Main()

    {

        object val1 = 123;

        object val2 = "10986423210";

        object thisNull = null;

        object thisInvalid = "A100";

        string format = "{0, -20} {1, -15}";

        Console.WriteLine(format, "Object", "ToNullableUInt64OrDefault");

        Console.WriteLine(format, "------", "-------------------------");

        // C# Extension Method: Object - ToNullableUInt64OrDefault

        Console.WriteLine(format, val1, val1.ToNullableUInt64OrDefault());

        Console.WriteLine(format, val2, val2.ToNullableUInt64OrDefault());

        Console.WriteLine(format, "null", thisNull.ToNullableUInt64OrDefault());

        Console.WriteLine(format, thisInvalid, thisInvalid.ToNullableUInt64OrDefault());

        Console.WriteLine(format, thisInvalid, thisInvalid.ToNullableUInt64OrDefault(1));

        Console.WriteLine(format, thisInvalid, thisInvalid.ToNullableUInt64OrDefault(() => 2));

    }

}