Set Default Value to Property in C#

In the previous article, I mentioned how to Convert C# Class to JSON with Example but in this article, I have mentioned how we can set default value to a C# Class property with an example.

If we are using C# 6 or above, we can simply use the below code to set or give a value to the Auto Property

public class DefaultValue
    {
        public string FirstName { get; set; } = "John Wick"; // default value = john wick
    }

So if we consider a complete Console application example, it would be as below

using System;

namespace DefaultCSharp
{
    internal class Program
    {
        static void Main(string[] args)
        {
            DefaultValue obj = new DefaultValue();
            Console.WriteLine(obj.FirstName);
        }
    }

    public class DefaultValue
    {
        public string FirstName { get; set; } = "John Wick";
    }
}

Output:

John Wick

Using DefaultValueAttribute

We can also use DefaultValueAttribute to property default value to a property, here is an example of using it

  private string _val = "Last Name Here";

        [DefaultValue(false)]
        public string LastName
        {
            get
            {
                return _val;
            }
            set
            {
                _val = value;
            }
        }

So, if we consider complete console application example, it would be as below

using System;
using System.ComponentModel;

namespace DefaultCSharp
{
    internal class Program
    {
        static void Main(string[] args)
        {
            DefaultValue obj = new DefaultValue();
            Console.WriteLine(obj.LastName);
        }
    }

    public class DefaultValue
    {
        private string _val = "Last Name Here";

        [DefaultValue(false)]
        public string LastName
        {
            get
            {
                return _val;
            }
            set
            {
                _val = value;
            }
        }
    }
}

Output:

Last Name Here

Using Constructor (For below C# 6)

If you are using C# 5 or below version, then to set default value you will have to use Constructor

So for above example, it would go like this

 public class DefaultValue
    {
        public DefaultValue()
        {
            FirstName = "John Wick";
        }
        public string FirstName { get; set; }
    }

Complete C# example, would be as below

using System;

namespace DefaultCSharp
{
    internal class Program
    {
        static void Main(string[] args)
        {
            DefaultValue obj = new DefaultValue();
            Console.WriteLine(obj.FirstName);
        }
    }

    public class DefaultValue
    {
        public DefaultValue()
        {
            FirstName = "John Wick";
        }
        public string FirstName { get; set; }
    }
}

Output:

John Wick

That's it, hope it helps.

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