ListViewPagedDataSource.cs :  » 2.6.4-mono-.net-core » System.Web » System » Web » UI » WebControls » C# / CSharp Open Source

//
// System.Web.UI.WebControls.ListView
//
// Authors:
//   Marek Habersack (mhabersack@novell.com)
//
// (C) 2007-2008 Novell, Inc
//

//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
#if NET_3_5
using System;
using System.Collections;
using System.ComponentModel;

namespace System.Web.UI.WebControls{
  public class ListViewPagedDataSource : ICollection, IEnumerable, ITypedList
  {
    sealed class ListEnumerator : IEnumerator
    {
      int index;
      int startIndex;
      int end;
      IList list;
      
      public object Current {
        get { return list [startIndex + index]; }
      }
      
      public ListEnumerator (IList list, int startIndex, int end)
      {
        this.list = list;
        this.index = -1;
        this.startIndex = startIndex;
        this.end = startIndex + end;
      }
      
      public bool MoveNext ()
      {
        index++;
        return (startIndex + index) < end;
      }

      // See:
      // http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.listviewpageddatasource.getenumerator.aspx
      // (Note 1)
      public void Reset ()
      {
        index = -1;
      }
    }

    sealed class CollectionEnumerator : IEnumerator
    {
      int index;
      int startIndex;
      int end;
      ICollection collection;
      IEnumerator enumerator;
      
      public object Current {
        get {
          if (enumerator != null)
            return enumerator.Current;

          return null;
        }
      }
      
      public CollectionEnumerator (ICollection collection, int startIndex, int end)
      {
        this.collection = collection;
        this.index = -1;
        this.startIndex = startIndex;
        this.end = end;
      }
      
      public bool MoveNext ()
      {
        if (enumerator == null) {
          enumerator = collection.GetEnumerator ();
          for (int i = 0; i < startIndex; i++)
            enumerator.MoveNext ();
        }
        
        index++;
        enumerator.MoveNext ();
        return (startIndex + index) < end;
      }

      // See:
      // http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.listviewpageddatasource.getenumerator.aspx
      // (Note 1)
      public void Reset ()
      {
        index = -1;
        enumerator = null;
      }
    }
    
    public ListViewPagedDataSource ()
    {
      StartRowIndex = 0;
      MaximumRows = 0;
      AllowServerPaging = false;
      TotalRowCount = 0;
    }
    
    public void CopyTo (Array array, int index)
    {
    }
    
    public IEnumerator GetEnumerator ()
    {
      IEnumerable ds = DataSource;

      if (ds == null)
        return null;

      IList list = ds as IList;
      if (list != null)
        return new ListEnumerator (list, AllowServerPaging ? 0 : StartRowIndex, Count);

      ICollection collection = ds as ICollection;
      if (collection != null)
        return new CollectionEnumerator (collection, AllowServerPaging ? 0 : StartRowIndex, Count);
      
      return ds.GetEnumerator ();
    }
    
    public PropertyDescriptorCollection GetItemProperties (PropertyDescriptor [] listAccessors)
    {
      IEnumerable ds = DataSource;

      if (ds == null || !(ds is ITypedList))
        return null;

      return ((ITypedList) ds).GetItemProperties (listAccessors);
    }
    
    public string GetListName (PropertyDescriptor [] listAccessors)
    {
      return String.Empty;
    }
    
    public bool AllowServerPaging {
      get;
      set;
    }
    
    public int Count {
      get {
        IEnumerable ds = DataSource;
        if (ds == null)
          return 0;

        bool onLastPage = OnLastPage;
        int maxRows = MaximumRows;
        if (!onLastPage && maxRows >= 0)
          return maxRows;

        // LAMESPEC: MSDN says that DataSourceCount should be subtracted
        // from StartRowIndex
        return DataSourceCount - StartRowIndex;
      }
    }
    
    public IEnumerable DataSource {
      get;
      set;
    }
    
    public int DataSourceCount {
      get {
        IEnumerable ds = DataSource;
        if (ds == null)
          return 0;

        if (!(ds is ICollection))
          throw new InvalidOperationException ("The data source object does not implement the System.Collections..::.ICollection interface.");

        if (IsServerPagingEnabled)
          return TotalRowCount;        

        return ((ICollection) ds).Count;
      }
    }
    
    public bool IsReadOnly {
      get { return false; }
    }
    
    public bool IsServerPagingEnabled {
      get { return AllowServerPaging; }
    }
    
    public bool IsSynchronized {
      get { return false; }
    }
    
    public int MaximumRows {
      get;
      set;
    }
    
    public int StartRowIndex {
      get;
      set;
    }
    
    public object SyncRoot {
      get { return this; }
    }
    
    public int TotalRowCount {
      get;
      set;
    }

    bool OnLastPage {
      get { return ((StartRowIndex + MaximumRows) >= DataSourceCount); }
    }
    
  }
}
#endif