Native CollectionView for swapping, sorting and filtering

Question

I implemented my own CollectionView to bind a data collection to a DataGrid in WPF.

The main goal is pagination, which works quite well. I wrote the following C # code:

public class SchemesCollectionView : CollectionView { private readonly IList<Scheme> innerList; private readonly int itemsPerPage; private int currentPage = 1; public SchemesCollectionView(IList<Scheme> source, int itemsPerPage) : base(source) { innerList = source; this.itemsPerPage = itemsPerPage; } public override int Count { get { return itemsPerPage; } } public int CurrentPage { get { return currentPage; } set { currentPage = value; OnPropertyChanged(new PropertyChangedEventArgs("CurrentPage")); OnPropertyChanged(new PropertyChangedEventArgs("FirstItemNumber")); OnPropertyChanged(new PropertyChangedEventArgs("LastItemNumber")); } } public int ItemsPerPage { get { return this.itemsPerPage; } } public int PageCount { get { return (this.innerList.Count() + this.itemsPerPage - 1) / this.itemsPerPage; } } public int LastItemNumber { get { var end = currentPage * itemsPerPage - 1; end = (end > innerList.Count()) ? innerList.Count() : end; return end + 1; } } public int StartIndex { get { return (currentPage - 1) * itemsPerPage; } } public int FirstItemNumber { get { return ((currentPage - 1) * itemsPerPage) + 1; } } public override object GetItemAt(int index) { var offset = index % (ItemsPerPage); var position = StartIndex + offset; if (position >= innerList.Count) { position = innerList.Count - 1; } return innerList[position]; } public void MoveToNextPage() { if (CurrentPage < PageCount) { CurrentPage += 1; } Refresh(); } public void MoveToPreviousPage() { if (CurrentPage > 1) { CurrentPage -= 1; } Refresh(); } public void MoveToFirstPage() { CurrentPage = 1; Refresh(); } public void MoveToLastPage() { CurrentPage = PageCount; Refresh(); } } 

As already mentioned, pagination works very well. But I can not do filtering and sorting. When I add my own filter to the Filter property, it is completely ignored. Same thing with sorting. I see arrows on the column headers after I clicked them, but different sorting is not reflected in the DataGrid.

What am I missing here? Hope someone can help.

Answer 1

As already mentioned, you can take the code from Silverlight and use it in WPF.

Paged Collection View in WPF

Answer 2

Here is a solution for filtering and paging using only the CollectionView class.

You just need to set the current page index and the maximum number of elements on the page to fit your needs.

  // obtenir la CollectionView ICollectionView cvCollectionView = CollectionViewSource.GetDefaultView(this.Suivis); if (cvCollectionView == null) return; // filtrer ... exemple pour tests DI-2015-05105-0 cvCollectionView.Filter = p_oObject => { return true; /* use your own filter */ }; // page configuration int iMaxItemPerPage = 2; int iCurrentPage = 0; int iStartIndex = iCurrentPage * iMaxItemPerPage; // déterminer les objects "de la page" int iCurrentIndex = 0; HashSet<object> hsObjectsInPage = new HashSet<object>(); foreach (object oObject in cvCollectionView) { // break if MaxItemCount is reached if (hsObjectsInPage.Count > iMaxItemPerPage) break; // add if StartIndex is reached if (iCurrentIndex >= iStartIndex) hsObjectsInPage.Add(oObject); // increment iCurrentIndex++; } // refilter cvCollectionView.Filter = p_oObject => { return cvCollectionView.Contains(p_oObject) && hsObjectsInPage.Contains(p_oObject); };