How can I add one more column to List<Products> ?

Question

1.00/5 (1 vote)

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I have a data table in db.

C#

ID || ProductName  || SoldDateTime
==================================
1  || Books         || 6543213571
2  || Pencils       || 1594563215
3  || Paint         || 5411865446
4  || Markers       || 2421375125
5  || Copies        || 5546423010
.  || .             || 7568714312

I added it in my project as ProdutEntityModel

Now i want to convert SoldDateTime into 01/24/2015 and the resultant i want List<product> how can i achieve this.

VB

ID || ProductName  || SoldDateTime ||      SDateTime
==========================================================
1  || Books         || 6543213571  || 01/01/2015  06:22:15
2  || Pencils       || 1594563215  || 01/08/2015  15:25:55
3  || Paint         || 5411865446  || 01/15/2015  23:45:32
4  || Markers       || 2421375125  || 01/22/2015  00:56:33
5  || Copies        || 5546423010  || 02/12/2015  18:04:50
.  || .             || .           || .

How can i do this in Linq to Entity.

Posted 11-Jan-15 0:12am

shaprpuff

Updated 11-Jan-15 0:15am

v2

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Comments

Tomas Takac 11-Jan-15 6:18am

What does the number in SoldDateTime mean? Is it ticks or what?

shaprpuff 11-Jan-15 6:21am

this is unix Numbers in seconds i converted it like this way,

DateTime s_date;
s_date = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
s_date = s_date.AddSeconds(Convert.ToDouble(item.SoldDateTime )).ToLocalTime();

Zoltán Zörgő 11-Jan-15 6:36am

1) code first or database first?
2) you want to add this calculated field to the table or to the model?

shaprpuff 11-Jan-15 7:11am

this is database first approach i want to add this new column into the existing list

List<Products> list=ctx.Products.ToList();

i want to add this new column list.

Zoltán Zörgő 11-Jan-15 8:36am

Supposing you have downvoted my answer, may I ask you why?

shaprpuff 12-Jan-15 5:18am

I did not down voted your answer.

3 solutions

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**Zoltán Zörgő** · Accepted Answer · 2015-01-11T01:32:00

Solution 1

This is the way: http://robbincremers.me/2012/01/31/entity-framework-using-partial-classes-to-add-business-logic-and-validation-to-generated-entities/[^]

Posted 11-Jan-15 1:32am

Zoltán Zörgő

Comments

Maciej Los 11-Jan-15 11:48am

+5! Sounds reasonable ;)

BillWoodruff 11-Jan-15 12:21pm

+5 That's a very good tutorial with excellent use of graphic design, and clear writing. Too bad the author uses bit-maps for all the code, and gives you no way to download it.

Maciej Los · Accepted Answer · 2015-01-11T06:03:00

As per my understanding, you can achieve that using 2 ways:
1. add partial class
See solution 1 by Zoltan Zorgo[^]
or
2. add not mapped field to your model

C#

[NotMapped]
public DateTime SDateTime {get; set;}

But you tag your question: Linq, so it might means you want to create query based on your model...

C#

var qry = from emd in EntityModelData
        select new {
            //get collection of your fields
            ID = ID,
            ProductName = ProductName,
            SoldDateTime = SoldDateTime,
            SDateTime = YourExtensionMethodToConvert(SoldDateTime)
        };

shaprpuff · Accepted Answer · 2015-01-11T23:36:00

Step1: Select only the required data.

C#

 List<products> prodlist = ctx.Products
                          .Where(
                          x => SqlFunctions.DateAdd("s", x.SoldDateTime , "1970-01-01").Value.Year==DateTime.Now.Year &&
                           SqlFunctions.DateAdd("s", x.SoldDateTime , "1970-01-01").Value.Month==DateTime.Now.Month  ).ToList();
                                               
                                              
</products>

Step2: I added Partial Class and not Mapped Property

C#

namespace MyShop
{
  public partial class Products
  {
    private DateTime s_date = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
    public DateTime SDateTime
    { 
      get 
      {
        return s_date.AddSeconds(Convert.ToDouble(this.SoldDateTime)).ToLocalTime();
      }
    } 
  }
}

I would like to thanks "Zoltan Zorgo" for this help.

How can I add one more column to List<Products> ?

3 solutions

Solution 1

Solution 2

Solution 3

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