How make default value in ASP.NET MVC

Question

I want to create a default color when I add a new event.

Now the color is set to NULL.

[HttpPost]
public JsonResult SaveEvent(Event e)
{
        var status = false;

        if (e.EventID > 0)
        {
            //Update the event
            var v = db.Events.Where(a => a.EventID == e.EventID).FirstOrDefault();
            if (v != null) 
            {
                v.EventTitle = e.EventTitle;

                v.EventDescription = e.EventDescription;
                v.ThemeColor = e.ThemeColor;
            }
        }
        else
        {
            db.Events.Add(e);
        }

        db.SaveChanges();
        status = true;

        return new JsonResult { Data = new { status = status } };
    }

How make ThemeColor red when I add the event ?

                public partial class Event
{
    public int EventID { get; set; }
    public string EventTitle { get; set; }
    public string EventDescription { get; set; }
    public Nullable<System.DateTime> StartDate { get; set; }
    public Nullable<System.DateTime> EndDate { get; set; }
    public string ThemeColor { get; set; }
}

you can override getter and setter: private string _themeColor; public string ThemeColor{ get => string.IsNullOrEmpty(_themeColor) ? "Red" : _themeColor; set => _themeColor = value;} — Dmitry
– Dmitry, Commented Jun 5, 2020 at 6:52

Borka · Accepted Answer · 2020-06-04 14:49:34Z

1

If you use c# 6 or higher, you can use this syntax to set the default value to a property

public string ThemeColor { get; set; } = "Red";

Otherwise you can initialize via constructor.

But if you are explicitly sending the ThemeColor as null in the payload, when invoking the method then you'll need to manually check if ThemeColor is null and set it in the controller

For example:

v.ThemeColor = e.ThemeColor ?? "Red";

EDIT:

You can add the null check on top of the method and with that you'll cover both cases

if(e.ThemeColor == null)
{
    e.ThemeColor = "Red";
}

edited Jun 4, 2020 at 14:49

answered Jun 4, 2020 at 7:39

Borka

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2 Comments

Aymen Ben Hassine Over a year ago

thank you but your solutions not work for me when i add a new event make me color is NULL and not red color

Borka Over a year ago

You went with the second example, with checking yourself in the code?

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