Linq if-elseif-else在asp.net中使用linq查询

Question

In my asp.net application i am using linq. I need a help what is the syntax for if-elseif-else using linq in single line.

genericReportList =
    (from CD in list
    select new GENERICREPORT
        {
            CITATIONNO = CD.CITATIONNO,
            DATE = CD.DATE,
            LOCATION = CD.LOCATION,
            //STATUS = CD.STATUS,
            PLATENO = Utilities.DecryptData(CD.PLATENO),
            PSOURCE = CD.PSOURCE,
            MAKE = CD.MAKE,
            ID = Utilities.DecryptData(CD.ID),
            NATIONALITY = CD.NATIONALITY,
            SOURCE = CD.SOURCE,
            NAME = Utilities.DecryptData(CD.NAME),
            VIOLATION = CD.VIOLATION,
            STATUS = CD.STATUS == short.Parse("1") ? "Complete" : "Incomplete"
        }).ToList();


If STATUS = CD.STATUS == short.Parse("1") ? "Complete" : and 2 for "Incomplete" and 3 for "Void"

Answer 1

I don't understand why you are doing short.Parse("1") . This will always be 1. If you want multiple if-else in a one-liner, combine ternary operators:

STATUS = CD.STATUS == 1 ? "Complete" : CD.STATUS == 2 ? "Incomplete" : "Void"

If this is going to be used in the context of Entity Framework (or other ORM with IQueryable support), it will translate to a CASE WHEN SQL statement.

Answer 2

What I understand from your question if I'm not wrong, is that you might be asking about where clause.

if yes then you can always use multiple where in your query.

example : 
Collection.Where(x => x.Age == 10)
      .Where(x => x.Name == "Fido")
      .Where(x => x.Fat == true)

more about LINQ query

http://msdn.microsoft.com/en-us/library/gg509017.aspx

Answer 3

您可以继续使用已有的内容。

STATUS = CD.STATUS == 1 ? "Complete" : (CD.STATUS == 2 ? "Incomplete" : "InProgress")

Answer 4

There nothing wrong with writing your own method and using it in a LINQ query. It will be far more understandable and readable than a long conditional operator.

Consider using something like:

private String GetStatus(int value)
{
    if (value == 1)
        return "Complete";
    if (value == 2)
        return "Incomplete";
    if (value == 3)
        return "Void";

}

Then you would call it like:

STATUS = GetStatus(CD.STATUS)