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From: gajendra.baragur on 25 Feb 2008 09:34 Hi Marc Gravell, Even i have similar problem what you have explained earlier for the above thread. I just want to clarify my doubt regarding IBindingListView. In my application i have used BindingSource that i have binded to a DataGridView that, BindingSource i have associated to a class with four properties. I'm able to display those property contents in the DataGridView but unable to filter it. I have 50 records in the BindingSource in that i need to filter only those records starting from the Itemid greater than 10 and lesser than or equal to 30. I have tried the below methods.... 1) itemsBindingSource.Filter = "Itemid > =" + 10 + " and Itemid <=" + 30; 2) temsBindingSource.Filter="Slno between " + startno + " and " + Endno; (This is what you have suggested in the last discussion) I tried itemsBindingSource.SupportsFiltering property eventhough it always returns false. Actually i'm implementing the above code for DataGridView paging, so that i can display few records using filter in a single page. Thanks in advance, Gajendra
From: Marc Gravell on 25 Feb 2008 09:51 I don't think it would be simple to apply paging using a filter; in particular, the code for adding/removing items (at the bottom of the DataGridView) would be a real pain. As it happens I do have a (predicate-oriented) filtered-list implementation up my sleeve, but I don't think it is a good fit for what you are doing... Being pragmatic, for paging, would it not be easier to simply copy the page that you want from your original list into the data-bound list? > (This is what you have suggested in the last discussion) Did I? I don't remember that, and can't see it in the archive... For info, this discussion was really about sorting, not filtering; they are very different beasts... If you are paging over a very large result, consider also "virtual mode". Marc
From: Gajendra on 26 Feb 2008 02:31 Hi Marc, Thanx for your reply... Basically I have an example of datagridview paging using dataset where he used to show the records in pages through filter condition. The following line is used for filter condition in that example. bindingSource1.Filter = "RecordID >= " + RecordID1 + " and RecordID <= " + RecordID2; GridView1.DataSource = bindingSource1; For your kind reference follow the link which has the above code.. http://www.codeproject.com/KB/miscctrl/Pagable_DatagridView.aspx The project which includes the above two statements is working fine & the supportsFiltering is also returning true. So now I want to implement the same through BindingSource using collections. Hence I have binded to a class which has four properties. The binding part & displaying in gridview is working fine.Now what I want exactly is, I want to display only 100 records in first page among 500 records. So i need to filter for a certain range so that it fulfils my requirement. Hope you understood my requirement. I am struggling for this part from past few days, so if u please help me in this regard as soon as possible, it will be very much appreciable. Thanks once again... Marc Gravell wrote: >I don't think it would be simple to apply paging using a filter; in >particular, the code for adding/removing items (at the bottom of the >DataGridView) would be a real pain. As it happens I do have a >(predicate-oriented) filtered-list implementation up my sleeve, but I >don't think it is a good fit for what you are doing... > >Being pragmatic, for paging, would it not be easier to simply copy the >page that you want from your original list into the data-bound list? > >> (This is what you have suggested in the last discussion) >Did I? I don't remember that, and can't see it in the archive... > >For info, this discussion was really about sorting, not filtering; >they are very different beasts... > >If you are paging over a very large result, consider also "virtual >mode". > >Marc
From: Marc Gravell on 26 Feb 2008 03:08
I understand whay you are trying to do... but using a filter is probably not going to be your best option here. The point is that BindingList<T> etc don't support filter "out of the box". I have a filtering example, but it is 556 LOC (mainly due to the complexities of dealing with full property notification over bound data. And this is the *simple* version that uses a predicate filter (not a parser). Quite simply - I think that a filtered list would be the wrong answer to your problem; all you need is paging... You don't indicate whay .NET version you are using - if you have 3.5 this would be even easier (Skip() and Take()), but since paging is so simple how about simply something like (note most of this code is the example; the list itself is very simple): using System; using System.Collections.Generic; using System.ComponentModel; using System.Windows.Forms; class DemoData { private int value1; private double value2; [DisplayName("Value 1")] public int Value1 { get { return value1; } set { value1 = value; } } [DisplayName("Value 2")] public double Value2 { get { return value2; } set { value2 = value; } } } static class Program { [STAThread] static void Main() { List<DemoData> data = new List<DemoData>(); Random rand = new Random(); for (int i = 0; i < 10000; i++) { DemoData dd = new DemoData(); dd.Value1 = rand.Next(500); dd.Value2 = rand.NextDouble() * 500; data.Add(dd); } Application.EnableVisualStyles(); using(Form form = new Form()) using (DataGridView view = new DataGridView()) using (Button next = new Button()) using (Button prev = new Button()) { PagedList<DemoData> paged = new PagedList<DemoData>(data, 0, 50); next.Click += delegate { paged.PageIndex += 1; }; prev.Click += delegate { paged.PageIndex -= 1; }; view.Dock = DockStyle.Fill; view.DataSource = paged; next.Dock = prev.Dock = DockStyle.Bottom; next.Text = ">"; prev.Text = "<"; form.Controls.AddRange(new Control[] { view, next, prev }); Application.Run(form); } } } class PagedList<T> : BindingList<T> { private readonly IList<T> source; public PagedList(IList<T> source) { if (source == null) throw new ArgumentNullException("source"); this.source = source; SetPage(0, source.Count); } public PagedList(IList<T> source, int pageIndex, int pageSize) { if (source == null) throw new ArgumentNullException("source"); this.source = source; SetPage(pageIndex, pageSize); } private int pageIndex, pageSize; public int PageIndex { get { return pageIndex; } set { SetPage(value, PageSize); } } public int PageSize { get { return pageSize; } set { SetPage(PageIndex, value); } } public void SetPage(int pageIndex, int pageSize) { if (pageIndex < 0) throw new ArgumentOutOfRangeException("pageIndex"); if (pageSize <= 0) throw new ArgumentOutOfRangeException("pageSize"); this.pageIndex = pageIndex; this.pageSize = pageSize; bool wasRaising = RaiseListChangedEvents; RaiseListChangedEvents = false; try { Clear(); int start = pageSize * pageIndex, end = start + pageSize; if (end > source.Count) end = source.Count; for (int i = start; i < end; i++) { Add(source[i]); } } finally { RaiseListChangedEvents = wasRaising; ResetBindings(); } } } |