pageddatasource.cs

不错的人事管理系统

using System;
using System.Collections;
using System.ComponentModel;

namespace System.Web.UI.WebControls
{
	/// <summary>
	/// Summary description for PagedDataSource.
	/// </summary>
	public class PagedDataSource :System.Collections.ICollection,
		System.Collections.IEnumerable,
		System.ComponentModel.ITypedList
	{
		class EnumeratorOnArray : System.Collections.IEnumerator
		{
			private object[] array;
			private int index;
			private int indexBounds;
			private int startIndex;

			public EnumeratorOnArray(object[] array, int startIndex, int count)
			{
				this.array = array;
				this.startIndex = startIndex;
				this.index = -1;
				this.indexBounds = startIndex + count;
				if (this.indexBounds > (int) array.Length)
					this.indexBounds = (int) array.Length;
			}


			public virtual void Reset() 
			{
				this.index = -1;
			}


			public virtual bool MoveNext() 
			{
				this.index = this.index + 1;
				return this.startIndex + this.index < this.indexBounds;
			}
			public virtual object Current
			{
				get
				{
					if (this.index < 0)
						throw new InvalidOperationException("Enumerator_MoveNext_Not_Called");
					return this.array[this.startIndex + this.index];
				}
			}
		}


		class EnumeratorOnIList : System.Collections.IEnumerator
		{
			private int index;
			private int indexBounds;
			private int startIndex;
			private System.Collections.IList collection;
			
			public EnumeratorOnIList(IList collection, int startIndex, int count) : base() 
			{
				this.collection = collection;
				this.startIndex = startIndex;
				this.index = -1;
				this.indexBounds = startIndex + count;
				if (this.indexBounds > collection.Count)
					this.indexBounds = collection.Count;
			}

			public virtual bool MoveNext() 
			{
				this.index = this.index + 1;
				return this.startIndex + this.index < this.indexBounds;
			}
			public virtual void Reset() 
			{
				this.index = -1;
			}

			public virtual object Current
			{
				get
				{
					if (this.index < 0)
						throw new InvalidOperationException("Enumerator_MoveNext_Not_Called");
					return this.collection[this.startIndex + this.index];
				}
			}


		}


		class EnumeratorOnICollection : System.Collections.IEnumerator
		{
			private int index;
			private int indexBounds;
			private int startIndex;
			private System.Collections.ICollection collection;
			private System.Collections.IEnumerator collectionEnum;

			public EnumeratorOnICollection(ICollection collection, int startIndex, int count) : base() 
			{
				this.collection = collection;
				this.startIndex = startIndex;
				this.index = -1;
				this.indexBounds = startIndex + count;
				if (this.indexBounds > collection.Count)
					this.indexBounds = collection.Count;
			}

			public virtual bool MoveNext() 
			{
				int local0;

				if (this.collectionEnum == null) 
				{
					this.collectionEnum = this.collection.GetEnumerator();
					local0 = 0;
					while (local0 < this.startIndex) 
					{
						this.collectionEnum.MoveNext();
						local0++;
					}
				}
				this.collectionEnum.MoveNext();
				this.index = this.index + 1;
				return this.startIndex + this.index < this.indexBounds;
			}

			public virtual void Reset() 
			{
				this.collectionEnum = null;
				this.index = -1;
			}

			public virtual object Current
			{
				get
				{
					return this.collectionEnum.Current;
				}
			}

		}


		class EnumeratorOnIEnumerator : System.Collections.IEnumerator
		{
			private int index;
			private int indexBounds;
			private System.Collections.IEnumerator realEnum;

			public EnumeratorOnIEnumerator(IEnumerator realEnum, int count) : base() 
			{
				this.realEnum = realEnum;
				this.index = -1;
				this.indexBounds = count;
			}

			
			public virtual bool MoveNext() 
			{
				bool local0;

				local0 = this.realEnum.MoveNext();
				this.index = this.index + 1;
				if (local0)
					return this.index < this.indexBounds;
				return false;
			}

			public virtual void Reset() 
			{
				this.realEnum.Reset();
				this.index = -1;
			}

			
			public virtual object Current
			{
				get
				{
					return this.realEnum.Current;
				}
			}


		}

		private System.Collections.IEnumerable dataSource;
		private int currentPageIndex;
		private int pageSize;
		private bool allowPaging;
		private bool allowCustomPaging;
		private int virtualCount;

		public PagedDataSource()
		{
			//
			// TODO: Add constructor logic here
			//
		}

		public virtual PropertyDescriptorCollection GetItemProperties(System.ComponentModel.PropertyDescriptor[] listAccessors) 
		{
			if (this.dataSource == null)
				return null;
			if (this.dataSource as ITypedList != null)
				return ((ITypedList) this.dataSource).GetItemProperties(listAccessors);
			return null;
		}

		public IEnumerable DataSource
		{
			get
			{
				return this.dataSource;
			}
			set
			{
				this.dataSource = value;
			}
		}

		public virtual void CopyTo(Array array, int index) 
		{
			IEnumerator local0;

			local0 = this.GetEnumerator();
			while (local0.MoveNext()) 
			{
				index = index + 1;
				array.SetValue(local0.Current, index);
			}
		}

		public virtual IEnumerator GetEnumerator() 
		{
			int local0;
			int local1;

			local0 = this.FirstIndexInPage;
			local1 = -1;
			if (this.dataSource as ICollection != null)
				local1 = this.Count;
			if (this.dataSource as IList != null)
				return new EnumeratorOnIList((IList) this.dataSource, local0, local1);
			if (this.dataSource as Array != null)
				return new EnumeratorOnArray((object[]) this.dataSource, local0, local1);
			if (this.dataSource as ICollection != null)
				return new EnumeratorOnICollection((ICollection) this.dataSource, local0, local1);
			if (this.allowCustomPaging)
				return new EnumeratorOnIEnumerator(this.dataSource.GetEnumerator(), this.Count);
			return this.dataSource.GetEnumerator();
		}

		public virtual string GetListName(System.ComponentModel.PropertyDescriptor[] listAccessors) 
		{
			return System.String.Empty;
		}

		
		public virtual int Count
		{
			get
			{
				if (this.dataSource == null)
					return 0;
				if (this.IsPagingEnabled) 
				{
					if (this.IsCustomPagingEnabled || !(this.IsLastPage))
						return this.pageSize;
					return this.DataSourceCount - this.FirstIndexInPage;
				}
				return this.DataSourceCount;
			}
		}

		public bool IsCustomPagingEnabled
		{
			get
			{
				if (this.IsPagingEnabled)
					return this.allowCustomPaging;
				return false;
			}
		}

		public bool IsLastPage
		{
			get
			{
				if (this.IsPagingEnabled)
					return this.CurrentPageIndex == this.PageCount - 1;
				return true;
			}
		}
		
		public virtual bool IsSynchronized
		{
			get
			{
				return false;
			}
		}

		public bool IsPagingEnabled
		{
			get
			{
				if (this.allowPaging)
					return this.pageSize != 0;
				return false;
			}
		}


		public virtual object SyncRoot
		{
			get
			{
				return this;
			}
		}

		public int FirstIndexInPage
		{
			get
			{
				if (this.dataSource == null || !(this.IsPagingEnabled))
					return 0;
				if (this.IsCustomPagingEnabled)
					return 0;
				return this.currentPageIndex * this.pageSize;
			}
		}

		public int CurrentPageIndex
		{
			get
			{
				return this.currentPageIndex;
			}
			set
			{
				this.currentPageIndex = value;
			}
		}

		public int DataSourceCount 
		{
			get
			{
				if (this.dataSource == null)
					return 0;
				if (this.IsCustomPagingEnabled)
					return this.virtualCount;
				if (this.dataSource as ICollection != null)
					return ((ICollection)this.dataSource).Count;
				throw new System.Web.HttpException(
					System.Web.HttpRuntime.FormatResourceString("PagedDataSource_Cannot_Get_Count")
					);
			}
		}

		public int PageCount
		{
			get
			{
				int local0;

				if (this.dataSource == null)
					return 0;
				local0 = this.DataSourceCount;
				if (this.IsPagingEnabled && local0 != 0)
					return local0 + this.pageSize - 1 / this.pageSize;
				return 1;
			}
		}

	}
}