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//------------------------------------------------------------------------------
// <copyright file="ReadOnlyHierarchicalDataSource.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Web.UI.WebControls {
using System;
using System.Collections;
using System.ComponentModel;
using System.Web;
using System.Web.UI;
using System.Web.Util;
/// <devdoc>
/// Helper class for hierarchical data bound controls to wrap an generic
/// data source with a strongly typed IHierarchicalDataSource. This class
/// automatically handles other IHierarchicalDataSources and
/// IHierarchicalEnumerables. This class uses
/// ReadOnlyHierarchicalDataSourceView to represent individual views.
/// </devdoc>
internal sealed class ReadOnlyHierarchicalDataSource : IHierarchicalDataSource {
private object _dataSource;
public ReadOnlyHierarchicalDataSource(object dataSource) {
Debug.Assert(dataSource == null || (dataSource is IHierarchicalEnumerable || dataSource is IHierarchicalDataSource), "Expected dataSource to be either null, an IHierarchicalEnumerable, or an IHierarchicalDataSource.");
_dataSource = dataSource;
}
#region Implementation of IHierarchicalDataSource
event EventHandler IHierarchicalDataSource.DataSourceChanged {
add {
}
remove {
}
}
/// <devdoc>
/// Check for IHierarchicalDataSource and IHierarchicalEnumerable, and
/// return an approprite HierarchicalDataSourceView.
/// </devdoc>
HierarchicalDataSourceView IHierarchicalDataSource.GetHierarchicalView(string viewPath) {
// Check first for IHierarchicalDataSource
IHierarchicalDataSource ds = _dataSource as IHierarchicalDataSource;
if (ds != null) {
return ds.GetHierarchicalView(viewPath);
}
IHierarchicalEnumerable enumerable = _dataSource as IHierarchicalEnumerable;
if (enumerable != null && viewPath != null && viewPath.Length != 0) {
throw new InvalidOperationException(SR.GetString(SR.ReadOnlyHierarchicalDataSourceView_CantAccessPathInEnumerable));
}
return new ReadOnlyHierarchicalDataSourceView(enumerable);
}
#endregion
}
}
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