|
//------------------------------------------------------------------------------
// <copyright file="ListViewPagedDataSource.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
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;
/// <devdoc>
/// <para>Initializes a new instance of the <see cref='System.Web.UI.WebControls.PagedDataSource'/> class.</para>
/// </devdoc>
public ListViewPagedDataSource() {
_allowServerPaging = false;
_totalRowCount = 0;
}
/// <devdoc>
/// <para>Indicates whether to implement page semantics on top of the underlying datasource.</para>
/// </devdoc>
public bool AllowServerPaging {
get {
return _allowServerPaging;
}
set {
_allowServerPaging = value;
}
}
/// <devdoc>
/// <para>
/// Specifies the number of items
/// to be used from the datasource.</para>
/// </devdoc>
[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;
}
}
}
/// <devdoc>
/// <para> Indicates the data source.</para>
/// </devdoc>
public IEnumerable DataSource {
get {
return _dataSource;
}
set {
_dataSource = value;
}
}
/// <devdoc>
/// </devdoc>
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);
}
}
}
}
/// <devdoc>
/// </devdoc>
private bool IsLastPage {
get {
if (StartRowIndex + MaximumRows >= DataSourceCount)
return true;
else
return false;
}
}
/// <devdoc>
/// </devdoc>
public bool IsReadOnly {
get {
return false;
}
}
/// <devdoc>
/// Indicates whether server-side paging is enabled
/// </devdoc>
public bool IsServerPagingEnabled {
get {
return _allowServerPaging;
}
}
/// <devdoc>
/// </devdoc>
[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;
}
}
/// <devdoc>
/// </devdoc>
[SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
public object SyncRoot {
get {
return this;
}
}
/// <devdoc>
/// </devdoc>
public int TotalRowCount {
get {
return _totalRowCount;
}
set {
_totalRowCount = value;
}
}
/// <devdoc>
/// </devdoc>
[SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
public void CopyTo(Array array, int index) {
for (IEnumerator e = this.GetEnumerator(); e.MoveNext(); )
array.SetValue(e.Current, index++);
}
/// <devdoc>
/// </devdoc>
[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();
}
}
}
/// <devdoc>
/// </devdoc>
[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;
}
/// <devdoc>
/// </devdoc>
[SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
public string GetListName(PropertyDescriptor[] listAccessors) {
return String.Empty;
}
/// <devdoc>
/// </devdoc>
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;
}
}
/// <devdoc>
/// </devdoc>
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;
}
}
/// <devdoc>
/// </devdoc>
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;
}
}
/// <devdoc>
/// </devdoc>
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;
}
}
}
}
|