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//------------------------------------------------------------------------------
// <copyright file="DataSourceHelper.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Web.UI {
using System;
using System.Collections;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Data;
internal sealed class DataSourceHelper {
private DataSourceHelper() {
}
internal static IEnumerable GetResolvedDataSource(object dataSource, string dataMember) {
if (dataSource == null)
return null;
IListSource listSource = dataSource as IListSource;
if (listSource != null) {
IList memberList = listSource.GetList();
if (listSource.ContainsListCollection == false) {
// the returned list is itself the list we need to bind to
// NOTE: I am ignoring the DataMember parameter... ideally we might have
// thrown an exception, but this would mess up design-time usage
// where the user may change the data source from a DataSet to a
// DataTable.
return (IEnumerable)memberList;
}
if ((memberList != null) && (memberList is ITypedList)) {
ITypedList typedMemberList = (ITypedList)memberList;
PropertyDescriptorCollection propDescs = typedMemberList.GetItemProperties(new PropertyDescriptor[0]);
if ((propDescs != null) && (propDescs.Count != 0)) {
PropertyDescriptor listProperty = null;
if (String.IsNullOrEmpty(dataMember)) {
listProperty = propDescs[0];
}
else {
listProperty = propDescs.Find(dataMember, true);
}
if (listProperty != null) {
object listRow = memberList[0];
object list = listProperty.GetValue(listRow);
if ((list != null) && (list is IEnumerable)) {
return (IEnumerable)list;
}
}
throw new HttpException(SR.GetString(SR.ListSource_Missing_DataMember, dataMember));
}
else {
throw new HttpException(SR.GetString(SR.ListSource_Without_DataMembers));
}
}
}
if (dataSource is IEnumerable) {
return (IEnumerable)dataSource;
}
return null;
}
}
}
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