Viewmodel to allow sorting and filtering for mvc contrib grid

In my attempt to enable sorting and filtering in conjunction with the MVC contrib. grid I have decided to use a Viewmodel which contains the grid data plus the sorting and filtering information. I added a form under the grid and the Viewmodel is used to maintain the state of the form and to carry the data for the grid:

public class GridViewModel<T>
    {
        public int Page {get; set;} // current page of grid
        public string OrderBy {get; set;} // name of the column
        public bool Asc {get; set;} 
        public string Operation {get; set;} // SW - Startswith, C - Contains
        public string Column {get; set;} // name of the column where operation takes place
        public string Argument {get; set;} // argument for operation
        public int RowsPerPage {get; set;} // visible number of rows per page

        public List<T> Data {get; set;}

        public GridViewModel(List<T> Data)
        {
            this.Data = Data;
        }
        public GridViewModel()
        {
            Page = 1;
            Asc = true;
            RowsPerPage = 10;
            Argument = "";
        }

        public int getNumberofPages()
        {
            return (int) Math.Ceiling(Convert.ToDouble(Data.Count) / Convert.ToDouble(RowsPerPage));
        }
    }

The form is created using HTMLHelpers and by passing in the Viewmodel.

The Viewmodel is created in a service method like this (not complete):

public GridViewModel<Bla> GetGridData(GridViewModel<Bla> GridViewModel)
        {
            IOrderedEnumerable<Bla> list = GetAllBlas();

            string Argument = GridViewModel.Argument.Trim();
            switch (GridViewModel.Column)
            {
                case "Age":
                    switch (GridViewModel.Operation)
                    {
                        case "SW":
                            list = list.Where(c => c.Age.ToString().StartsWith(Argument)).OrderBy(c => c.ProposalDateTime);
                            break;
                        case "C":
                            list = list.Where(c => c.Age.ToString().Contains(Argument)).OrderBy(c => c.ProposalDateTime);
                            break;
                        default:
                            break;
                    }
                    break;

                default:
                    break;
            }

            int start_index = (GridViewModel.RowsPerPage * GridViewModel.Page) - GridViewModel.RowsPerPage;

            switch (GridViewModel.OrderBy)
            {
                case "Age":
                    list = GridViewModel.Asc == true ? list.OrderBy(c => c.Age) : list.OrderByDescending(c => c.Age);
                    break;
                case "ProposalDateTime":
                    list = GridViewModel.Asc == true ? list.OrderBy(c => c.ProposalDateTime) : list.OrderByDescending(c => c.ProposalDateTime);
                    break;
                case "UpdateDateTime":
                    list = GridViewModel.Asc ==开发者_开发问答 true ? list.OrderBy(c => c.UpdateDateTime) : list.OrderByDescending(c => c.UpdateDateTime);
                    break;
                default:
                    list = GridViewModel.Asc == true ? list.OrderBy(c => c.ProposalDateTime) : list.OrderByDescending(c => c.ProposalDateTime);
                    break;
            }

            int number_of_rows = list.Count();
            if (start_index > number_of_rows)
            {
                start_index = 0;
            }

            GridViewModel.Data = list.Skip<Bla>((int)start_index).Take<Bla>((int)GridViewModel.RowsPerPage).ToList();

            return GridViewModel;
        }

This works but does not feel right yet ...

I am just wondering whether this code could be improved – has someone done something similar? Any feedback would be very much appreciated. Many thanks in advance.

Best wishes,

Christian

The closest thing to an answer can be found here (proposed by: Sergey Prokhorenko):

http://sprokhorenko.blogspot.com/2009/12/dedicated-to-my-wife.html

It is jqgrid specific but provided me with some ideas.

Christian