Custom attributes & Enum 2

Display values of custom attribute in Drop Down

Is there any advantage of adding custom attribute in Enum?

I want to bind some Cartoon Character names to drop down box; these values keep as Enum in my project. As we all know Enums doesn’t support spaces and special characters. So… use custom attribute

Method to get Enum as a collection

        public static IEnumerable<CartoonCharacters> GetCommenttype()
        {
            yield return CartoonCharacters.TinTin;
            yield return CartoonCharacters.SpongeBob;
            yield return CartoonCharacters.SpiderMan;
            yield return CartoonCharacters.BugsBunny;
            yield return CartoonCharacters.TomAndJerry;
            yield return CartoonCharacters.DonaldDuck;
        }

If you think yield keyword is new to you, I found two great articles

Using C# Yield for Readability and Performance
Behind the scenes of the C# yield keyword

Method to bind data

        public static Dictionary<CartoonCharacters, string> GetCartoonCharacters()
        {
            var list = new Dictionary<CartoonCharacters, string>();

            foreach (CartoonCharacters item in GetCommenttype())
            {
                list.Add(item, GetDescription(item));
            }
           
            return list;
        }

Don’t forget to bind data collection with drop down

 ddlCartoonCharacters.DataSource = GetCartoonCharacters();
 ddlCartoonCharacters.DataTextField = "value";
 ddlCartoonCharacters.DataValueField = "key";
 ddlCartoonCharacters.DataBind();

Final look

Custom attributes & Enum

Formal introduction to Enum: provides an efficient way to define a set of named integral constants that may be assigned to a variable.

As we use enums in our day today life, we may need small improvements and additional things integrated with enums.

This is my Enum (without custom attribute)

public enum CartoonCharacters
{
    TinTin = 1,
    SpongeBob = 2,
    SpiderMan = 3,
    BugsBunny = 4,
    TomAndJerry = 5,
    DonaldDuck = 6
}

I’m going to integrate descriptive text (some extra values) with my CartoonCharacters enum.

Enum with Description

public enum CartoonCharacters
{
    [Description("Tin Tin")]
    TinTin = 1,
 
    [Description("Sponge Bob")]
    SpongeBob = 2,
 
    [Description("Spider Man")]
    SpiderMan = 3,
 
    [Description("Bugs Bunny")]
    BugsBunny = 4,
 
    [Description("Tom And Jerry")]
    TomAndJerry = 5,
 
    [Description("Donald Duck")]
    DonaldDuck = 6
}
 
public class Description : Attribute
   {
       public string Text;
      
       public Description(string text)
       {
           Text = text;
       }
   }

  Method to read the description

    public static string GetDescription(Enum en)
    {
        Type type = en.GetType();
        MemberInfo[] memInfo = type.GetMember(en.ToString());

        if (memInfo != null && memInfo.Length > 0)
        {
            object[] attrs = memInfo[0].GetCustomAttributes(typeof(Description), false);

            if (attrs != null && attrs.Length > 0)
                return ((Description)attrs[0]).Text;
        }
        return en.ToString();
    }

Pivot with LINQ

Problem

I have SQL table with full of data and I want to present those data in my web page. The problem is SQL table & expected presentation structure was different.

SQL table:

The way I want to present:

Solution

So I have two options, pivot table with SQL query or with LINQ.

Pivot with SQL query :

select * from Package_Test

pivot (max(cost) for Staytype

in ([Home Stays],[Standard],[1st Class],[Superior],[Deluxe],[Boutique])) as packageStaytypeCost

Query result:

Pivot with LINQ:

var aa = DBContext.Package_Test

.GroupBy(a => a.BaseContent_Title)

.Select(g => new

{

Name = g.Key,

HomeStays = g.Where(c => c.StayType.Equals("Home Stays")).Select(c => c.Cost),

Standard = g.Where(c => c.StayType.Equals("Standard")).Select(c => c.Cost),

FirstClass = g.Where(c => c.StayType.Equals("1st Class")).Select(c => c.Cost),

Superior = g.Where(c => c.StayType.Equals("Superior")).Select(c => c.Cost),

Deluxe = g.Where(c => c.StayType.Equals("Deluxe")).Select(c => c.Cost),

Boutique = g.Where(c => c.StayType.Equals("Boutique")).Select(c => c.Cost),

}

).ToList();

LINQ result:

If you want to try this example, use following scripts to create table & insert data set

CREATE TABLE [dbo].[Package_Test](

[BaseContent_Title] [nvarchar](150) NULL,

[StayType] [nvarchar](50) NULL,

[Cost] [int] NULL

) ON [PRIMARY]

INSERT [dbo].[Package_Test] ([BaseContent_Title], [StayType], [Cost]) VALUES (N'One Night on Half Board Per person and Twin Sharing', N'Home Stays', 200)

INSERT [dbo].[Package_Test] ([BaseContent_Title], [StayType], [Cost]) VALUES (N'One Night on Half Board Per person and Twin Sharing', N'Standard', 70)

INSERT [dbo].[Package_Test] ([BaseContent_Title], [StayType], [Cost]) VALUES (N'One Night on Half Board Per person and Twin Sharing', N'1st Class', 110)

INSERT [dbo].[Package_Test] ([BaseContent_Title], [StayType], [Cost]) VALUES (N'One Night on Half Board Per person and Twin Sharing', N'Superior', 90)

INSERT [dbo].[Package_Test] ([BaseContent_Title], [StayType], [Cost]) VALUES (N'One Night on Half Board Per person and Twin Sharing', N'Deluxe', 200)

INSERT [dbo].[Package_Test] ([BaseContent_Title], [StayType], [Cost]) VALUES (N'One Night on Half Board Per person and Twin Sharing', N'Boutique', 400)

INSERT [dbo].[Package_Test] ([BaseContent_Title], [StayType], [Cost]) VALUES (N'Two Nights on Half Board Per person and Twin Sharing', N'Home Stays', 200)

INSERT [dbo].[Package_Test] ([BaseContent_Title], [StayType], [Cost]) VALUES (N'Two Nights on Half Board Per person and Twin Sharing', N'Standard', 100)

INSERT [dbo].[Package_Test] ([BaseContent_Title], [StayType], [Cost]) VALUES (N'Two Nights on Half Board Per person and Twin Sharing', N'1st Class', 150)

INSERT [dbo].[Package_Test] ([BaseContent_Title], [StayType], [Cost]) VALUES (N'Two Nights on Half Board Per person and Twin Sharing', N'Superior', 225)

INSERT [dbo].[Package_Test] ([BaseContent_Title], [StayType], [Cost]) VALUES (N'Two Nights on Half Board Per person and Twin Sharing', N'Deluxe', 300)

INSERT [dbo].[Package_Test] ([BaseContent_Title], [StayType], [Cost]) VALUES (N'Two Nights on Half Board Per person and Twin Sharing', N'Boutique', 400)

Hi.....

Here is Madhuka's first post.... :)