ListViewPagedDataSource.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / xsp / System / Extensions / UI / WebControls / ListViewPagedDataSource.cs / 1305376 / ListViewPagedDataSource.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

using System; 
using System.Collections; 
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis; 
using System.Web;
using System.Web.Resources;
using System.Web.UI;
 
namespace System.Web.UI.WebControls {
    [ 
    SuppressMessage("Microsoft.Naming", "CA1710:IdentifiersShouldHaveCorrectSuffix", 
                    Justification = "Type is a generalized data structure that happens to implement ICollection"),
    ] 
    public class ListViewPagedDataSource : ICollection, ITypedList {

        private IEnumerable _dataSource;
        private bool _allowServerPaging; 

        private int _startRowIndex; 
        private int _maximumRows; 
        private int _totalRowCount;
 

        /// 
        /// Initializes a new instance of the  class.
        ///  
        public ListViewPagedDataSource() {
            _allowServerPaging = false; 
            _totalRowCount = 0; 
        }
 
        /// 
        /// Indicates whether to implement page semantics on top of the underlying datasource.
        /// 
        public bool AllowServerPaging { 
            get {
                return _allowServerPaging; 
            } 
            set {
                _allowServerPaging = value; 
            }
        }

 
        /// 
        ///     
        ///       Specifies the number of items 
        ///       to be used from the datasource.
        ///  
        [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
        public int Count {
            get {
                if (_dataSource == null) 
                    return 0;
 
                if (IsLastPage == false) { 
                    // In custom paging the datasource can contain at most
                    // a single page's worth of data. 
                    // In non-custom paging, all pages except last one have
                    // a full page worth of data.
                    if (MaximumRows >= 0) {
                        return MaximumRows; 
                    }
                    else { 
                        return DataSourceCount - StartRowIndex; 
                    }
                } 
                else {
                    // last page might have fewer items in datasource
                    return DataSourceCount - StartRowIndex;
                } 
            }
        } 
 

        ///  
        ///     Indicates the data source.
        /// 
        public IEnumerable DataSource {
            get { 
                return _dataSource;
            } 
            set { 
                _dataSource = value;
            } 
        }


        ///  
        /// 
        public int DataSourceCount { 
            get { 
                if (_dataSource == null)
                    return 0; 
                if (IsServerPagingEnabled) {
                    return _totalRowCount;
                }
                else { 
                    if (_dataSource is ICollection) {
                        return ((ICollection)_dataSource).Count; 
                    } 
                    else {
                        // The caller should not call this in the case of an IEnumerator datasource 
                        // This is required for paging, but the assumption is that the user will set
                        // up custom paging.
                        throw new InvalidOperationException(AtlasWeb.ListViewPagedDataSource_CannotGetCount);
                    } 
                }
            } 
        } 

        ///  
        /// 
        private bool IsLastPage {
            get {
                if (StartRowIndex + MaximumRows >= DataSourceCount) 
                    return true;
                else 
                    return false; 
            }
        } 

        /// 
        /// 
        public bool IsReadOnly { 
            get {
                return false; 
            } 
        }
 

        /// 
        /// Indicates whether server-side paging is enabled
        ///  
        public bool IsServerPagingEnabled {
            get { 
                return _allowServerPaging; 
            }
        } 


        /// 
        ///  
        [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
        public bool IsSynchronized { 
            get { 
                return false;
            } 
        }

        public int MaximumRows {
            get { 
                return _maximumRows;
            } 
            set { 
                _maximumRows = value;
            } 
        }

        public int StartRowIndex {
            get { 
                return _startRowIndex;
            } 
            set { 
                _startRowIndex = value;
            } 
        }

        /// 
        ///  
        [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
        public object SyncRoot { 
            get { 
                return this;
            } 
        }


        ///  
        /// 
        public int TotalRowCount { 
            get { 
                return _totalRowCount;
            } 
            set {
                _totalRowCount = value;
            }
        } 

 
        ///  
        /// 
        [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")] 
        public void CopyTo(Array array, int index) {
            for (IEnumerator e = this.GetEnumerator(); e.MoveNext(); )
                array.SetValue(e.Current, index++);
        } 

        ///  
        ///  
        [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
        public IEnumerator GetEnumerator() { 
            int startRowIndex = 0;
            int count = -1;

            if (!IsServerPagingEnabled) { 
                startRowIndex = StartRowIndex;
            } 
 
            if (_dataSource is ICollection) {
                count = Count; 
            }

            if (_dataSource is IList) {
                return new EnumeratorOnIList((IList)_dataSource, startRowIndex, count); 
            }
            else if (_dataSource is Array) { 
                return new EnumeratorOnArray((object[])_dataSource, startRowIndex, count); 
            }
            else if (_dataSource is ICollection) { 
                return new EnumeratorOnICollection((ICollection)_dataSource, startRowIndex, count);
            }
            else {
                if (_allowServerPaging) { 
                    // startRowIndex does not matter
                    // however count does... even if the data source contains more than 1 page of data in 
                    // it, we only want to enumerate over a single page of data 
                    // note: we can call Count here, even though we're dealing with an IEnumerator
                    //       because by now we have ensured that we're in custom paging mode 
                    return new EnumeratorOnIEnumerator(_dataSource.GetEnumerator(), Count);
                }
                else {
                    // startRowIndex and count don't matter since we're going to enumerate over all the 
                    // data (either non-paged or custom paging scenario)
                    return _dataSource.GetEnumerator(); 
                } 
            }
        } 


        /// 
        ///  
        [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
        public PropertyDescriptorCollection GetItemProperties(PropertyDescriptor[] listAccessors) { 
            if (_dataSource == null) 
                return null;
 
            if (_dataSource is ITypedList) {
                return ((ITypedList)_dataSource).GetItemProperties(listAccessors);
            }
            return null; 
        }
 
 
        /// 
        ///  
        [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
        public string GetListName(PropertyDescriptor[] listAccessors) {
            return String.Empty;
        } 

 
 
        /// 
        ///  
        private sealed class EnumeratorOnIEnumerator : IEnumerator {
            private IEnumerator realEnum;
            private int index;
            private int indexBounds; 

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

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

            public bool MoveNext() { 
                bool result = realEnum.MoveNext();
                index++;
                return result && (index < indexBounds);
            } 

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


        ///  
        /// 
        private sealed class EnumeratorOnICollection : IEnumerator { 
            private ICollection collection; 
            private IEnumerator collectionEnum;
            private int startRowIndex; 
            private int index;
            private int indexBounds;

            public EnumeratorOnICollection(ICollection collection, int startRowIndex, int count) { 
                this.collection = collection;
                this.startRowIndex = startRowIndex; 
                this.index = -1; 

                this.indexBounds = startRowIndex + count; 
                if (indexBounds > collection.Count) {
                    indexBounds = collection.Count;
                }
            } 

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

            public bool MoveNext() {
                if (collectionEnum == null) { 
                    collectionEnum = collection.GetEnumerator();
                    for (int i = 0; i < startRowIndex; i++) 
                        collectionEnum.MoveNext(); 
                }
                collectionEnum.MoveNext(); 
                index++;
                return (startRowIndex + index) < indexBounds;
            }
 
            public void Reset() {
                collectionEnum = null; 
                index = -1; 
            }
        } 



        ///  
        /// 
        private sealed class EnumeratorOnIList : IEnumerator { 
            private IList collection; 
            private int startRowIndex;
            private int index; 
            private int indexBounds;

            public EnumeratorOnIList(IList collection, int startRowIndex, int count) {
                this.collection = collection; 
                this.startRowIndex = startRowIndex;
                this.index = -1; 
 
                this.indexBounds = startRowIndex + count;
                if (indexBounds > collection.Count) { 
                    indexBounds = collection.Count;
                }
            }
 
            public object Current {
                get { 
                    if (index < 0) { 
                        throw new InvalidOperationException(AtlasWeb.ListViewPagedDataSource_EnumeratorMoveNextNotCalled);
                    } 
                    return collection[startRowIndex + index];
                }
            }
 
            public bool MoveNext() {
                index++; 
                return (startRowIndex + index) < indexBounds; 
            }
 
            public void Reset() {
                index = -1;
            }
        } 

 
 
        /// 
        ///  
        private sealed class EnumeratorOnArray : IEnumerator {
            private object[] array;
            private int startRowIndex;
            private int index; 
            private int indexBounds;
 
            public EnumeratorOnArray(object[] array, int startRowIndex, int count) { 
                this.array = array;
                this.startRowIndex = startRowIndex; 
                this.index = -1;

                this.indexBounds = startRowIndex + count;
                if (indexBounds > array.Length) { 
                    indexBounds = array.Length;
                } 
            } 

            public object Current { 
                get {
                    if (index < 0) {
                        throw new InvalidOperationException(AtlasWeb.ListViewPagedDataSource_EnumeratorMoveNextNotCalled);
                    } 
                    return array[startRowIndex + index];
                } 
            } 

            public bool MoveNext() { 
                index++;
                return (startRowIndex + index) < indexBounds;
            }
 
            public void Reset() {
                index = -1; 
            } 
        }
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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ListViewPagedDataSource.cs source code in C# .NET

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