Sorting a collection by multiple fields

Question

I need to sort a collection. For example, I have

Austin 12/3/2012   
Sam 100 12/3/2012   
Sam 200 14/3/2012   
Bubly 300 12/3/2012   
Bubly 300 15/3/2012  
         


        

Answer 1

I would create a class to hold your information

public class NameDate
{
    private string name;
    private DateTime date;
    public string Name
    {
        get { return name; }
        set { name = value; }
    }
    public DateTime Date
    {
        get { return date; }
        set { date = value; }
    }
}

I would then populate a List<NameDate> to hold your items. When this is done, to sort the items you can use LINQ

List<NameDate> someList = new List<NameDate>();
someList = GetNameDateList();
var orderedByNameList = someList.OrderBy(e => e.Name);
var orderedByDateTimeList = someList.OrderBy(e => e.Date);

I hope this helps.

Answer 2

You can use Linq function ThenBy after using OrderBy to perform further sorting.

listOfRecords.OrderBy(p => p.Name).ThenBy(p => p.Date)

Answer 3

Something like this:

yourList.OrderBy(o => o.DateTime).ThenBy(o => o.Number);

Answer 4

First you create two functions:

var SortByDate=(p=>p.Date);
var SortByName=(p=>p.Name);

Then you have, for example, a List containing the two

var SortDimensions=new List<object>({SortByDate,SortByName});

Then you if you want to sort by first date then name you do:

myList.OrderBy(SortDimensions[0]).ThenBy(SortDimensions[1]);

Now, here is the tricky part, if you want to sort by name first then date you just alter the order of the functions in the SortDimensionsList:

SortDimensions.Remove(SortByName);
SortDimensions.Insert(0,SortByName);

This way, the same OrderBy statement will give you a different result.

PS. Admittedly, this is rather close to being pseudocode since you may have to use something other than List<object> for the SortDimensions collection to avoid compiler errors, but I don't have access to an IDE at the moment, but the spirit of the answer remains the same. Create a collection, store delegate functions in it, then alter the order within the collection to achieve different sorting dimensions using the same generic code.