Sort List of Dictionaries

I have a collection of dictionary values (a List<>) that I need to sort. Basically each dictionary is a 'row' and the collection is a page of rows. A simple example;

       var data = new List<Dictionary<string,string>>();
       data.Add(new Dictionary<string,string>() {
                    { "Firstname", "Bob"},
                    { "Lastname", "Banana"}
       });
       data.Add(new Dictionary<string, string>() {
                    { "Firstname", "Amy"},
                    { "Lastname", "Apple"}
       });
       data.Add(new Dictionary<string, string>() {
                    { "Firstname", "Charlie"},
                    { "Lastname", "Coconut"}
       });
       data.Add(new Dictionary<string, string>() {
                    { "Firstname", "Andy"},
                    { "Lastname", "Apple"}
       });

The sort string generated is "SQL" like, example

 Lastname asc, Firstname desc

I have t开发者_StackOverflow社区ried .OrderBy() on the data object but that doesn't seem to work right against the KeyValuePairs.

Any idea how I could get the data list to be sorted to be in this order, using the dynamic sort statement:

 Apple, Andy
 Apple, Amy
 Banana, Bob
 Coconut, Charlie

Using .NET 4.0 if some fancy LINQ will work. Thanks for any suggestions.

data.OrderBy(dict => dict["Lastname"])
    .ThenByDescending(dict => dict["Firstname"])

If it's dynamic:

var sorted = data.OrderBy(item => 1); // identity (stable) sort
orderby = "Lastname asc, Firstname desc";
foreach (var key in orderby.Split(',').Select(clause => clause.Trim()))
{
    if (key.EndsWith(" desc", StringComparison.CurrentCultureIgnoreCase))
    {
        key = key.Substr(0, key.Length - 5);
        sorted = data.ThenByDescending(dict => dict[key]);
    } else
    {
        if (key.EndsWith(" asc", StringComparison.CurrentCultureIgnoreCase)) 
        {
            key = key.Substr(0, key.Length - 4);
        }
        sorted = data.ThenBy(dict => dict[key]);
    }
}

  private static IEnumerable<Dictionary<string, string>> Sort(IEnumerable<Dictionary<string,string>> data, string orderByString)
  {
     var orderBy =
        orderByString.Split(',').Select(
           s => s.Split(new[] {' '}, StringSplitOptions.RemoveEmptyEntries))
           .Select (a => new {Field=a[0],Descending = "desc".Equals (a[1], StringComparison.InvariantCultureIgnoreCase)})
           .ToList ();
     if (orderBy.Count == 0)
        return data;
     // First one is OrderBy or OrderByDescending.
     IOrderedEnumerable<Dictionary<string, string>> ordered =
        orderBy[0].Descending ? data.OrderByDescending (d => d[orderBy[0].Field]) : data.OrderBy (d => d[orderBy[0].Field]);
     for (int i = 1; i < orderBy.Count; i++)
     {
        // Rest are ThenBy or ThenByDescending.
        var orderClause = orderBy[i];
        ordered =
           orderBy[i].Descending ? ordered.ThenByDescending(d => d[orderClause.Field]) : ordered.ThenBy(d => d[orderClause.Field]);
     }
     return ordered;
  }

I'm not sure if you have the best implementation here, but as the above is an example and not a real world case, here you go:

data
.OrderBy(x => x["Lastname"])
.ThenByDescending(x => x["Firstname"])
.Select(x => 
    new 
    { 
        Lastname = x["Lastname"],
        Firstname = x["Firstname"],
    });

Unless there is a specific reason you need to use Dictionaries, for which I can't think, something similiar to this would be better;

public class Person
{
    public string FirstName {get; set;}
    public string LastName  {get; set;}
}

var people = new [] {
    new Person { FirstName = "Amy", LastName = "Apple" },
    new Person { FirstName = "Andy", LastName = "Apple" },
    new Person { FirstName = "Charlie", LastName = "Coconut" } 
};

var sortedPeople = people
    .OrderBy(f => f.LastName)
    .ThenByDescending(f => f.FirstName);

Updated based on comments;

See this post for a possible solution;

Entity Framework 4.1 simple dynamic expression for object.property = value

and

Dynamic linq query with multiple/unknown criteria

(the above has now been fully implemented as below)

public static int UpdateSegment(int segmentId)
{
    Table<ContactViewItem> Contacts;
    var  conditionsFormatted = new Dictionary<string, string>();

    //Retrieve all conditions
    var segmentConditions = Lists.GetSegmentConditions(segmentId);

    //Iterate through conditions and process them
    foreach (var condition in segmentConditions)
    {
        switch (condition.Operator)
        {
            case SegmentCondition.OperatorType.Equals:
                condition.Condition =  string.Format("{1}=\"{0}\"", condition.Criteria, condition.Field);
                break;
            case SegmentCondition.OperatorType.Contains:
                condition.Condition = string.Format("{1}.Contains(\"{0}\")", condition.Criteria, condition.Field);
                break;
            default:
                throw new ApplicationException("Unexpected Operator for Condition");
        }
    }


    var db = new DbContext(ConfigurationManager.ConnectionStrings["c"].ConnectionString);

    var statusConditions = "Status = 1";

    var results = (IQueryable)db.Contacts.Where(statusConditions);

    var distinctFields = (from c in segmentConditions select c.Field).Distinct();

    foreach (var distinctField in distinctFields)
    {
        var values = (from s in segmentConditions where s.Field == distinctField select s.Condition).ToArray();
        var valuesJoined = string.Join("||", values);
        results = results.Where(valuesJoined);
    }

    results = results.Select("id");


    var xml = new StringBuilder();
    xml.Append("<Ids>");

    foreach (var id in results)
    {
        xml.Append(String.Format("<Id>{0}</Id>", id));
    }
    xml.Append("</Ids>");

    var idXml = XDocument.Parse(xml.ToString());

    return Lists.UpdateSegmentContacts(idXml.ToString(), segmentId);

}

Might help, then again, might not!