DataSourceHelper.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / xsp / System / Web / UI / DataSourceHelper.cs / 1 / DataSourceHelper.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

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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