Enum datatype conversion to string

Question

How do I convert an enum datatype from int to string?

Here is my code below

public class Users_Accounts
{
    [Key]
    public int AccountID { get; set; }
    public Guid UniqueID { get; set; }

    [EnumDataType(typeof(string), ErrorMessage = "{0} Opps")]
    public Title Title { get; set; }
    public string First_Name { get; set; }
    public string Last_Name { get; set; }
}

and here is my Title enum:

public enum Title
{
    Mr, Mrs, Miss, Chief 
}

I get the error

InvalidCastException: Unable to cast object of type 'System.String' to type 'System.Int32'.

I know enums are strongly type and have a value of int, and in my database its nvarchar(20)

How do I convert it?

Many thanks

An enum for an honorific seems a bad idea since they are so often optional - some people do not like to say and if their title was Khaleesi of the Great Grass Sea, Breaker of Chains, Mother of Dragons well, you missed that one — Ňɏssa Pøngjǣrdenlarp
– Ňɏssa Pøngjǣrdenlarp, Commented Nov 18, 2018 at 17:26
@TânNguyễn because the values in the database are of string. By the way, i watched your videos on youtube ? Great vids — Ehi
– Ehi, Commented Nov 18, 2018 at 20:35

Tân · Accepted Answer · 2018-11-19 05:28:56Z

I will provide you an example that you can try but it's just a quick solution since you didn't design database structure.

Enum item:

public enum Title
{
    Mr, 
    Mrs, 
    Miss, 
    Chief 
}

By default, Title.Mr should have the default value 0, Mrs has value 1..., same to the orthers.

If you have 256 items or lower in the enum, you could try:

public enum Title : byte
{
    Mr = 0, 
    Mrs = 1, 
    Miss = 2, 
    Chief = 3
}

Title.Mr still has value 0.

The entity:

public class Users_Accounts
{
    [Key]
    public int AccountID { get; set; }
    public Guid UniqueID { get; set; }

    //You can change the returned type of `Title` property from `Title` to `string` here
    public string Title { get; set; }
    public string First_Name { get; set; }
    public string Last_Name { get; set; }
}

The model:

public class AddUserViewModel
{
    public Title Title { get; set; }
    public string First_Name { get; set; }
    public string Last_Name { get; set; }
}

When updating to database, you need to convert enum to a string:

public IActionResult AddUser(AddUserViewModel model)
{
    // title contains value like: 0, 1, 2... as string
    string title = ((int)model.Title).ToString();

    var user = new Users_Accounts
    {
        AccountID = ...
        UniqueID = ...
        Title = title,
        First_Name = model.First_Name,
        Last_Name = model.Last_Name
    };

    _dbContext.UserAccounts.Add(user);

    _dbContext.SaveChanges();
}

When you get some user, you can convert the Title as string to enum:

var user = _dbContext.UserAccounts.SingleOrDefault(x => x.AccountID == 1);
Title userTitle = (Title)Convert.ToInt32(user.Title);

userTitle would return Title.Mr or Title.Mrs...

NOTE: If you decide to use

public enum Title : byte {}

You need to change Convert.ToInt32 to Convert.ToByte instead.

Must say, this is quite intelligent coding and it works. Thank you

Ehi · Accepted Answer · 2018-11-30 15:07:45Z

0

I also found this online, and though its MVC 5 changing View.Bag to View["Data"] it works

https://www.c-sharpcorner.com/article/different-ways-bind-the-value-to-razor-dropdownlist-in-aspnet-mvc5/

answered Nov 30, 2018 at 15:07

Ehi

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