mcs/class/referencesource/System.Data/System/Data/OleDb/OleDbEnumerator.cs

   1 //------------------------------------------------------------------------------
   2 // <copyright file="OleDbEnumerator.cs" company="Microsoft">
   3 //      Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 // <owner current="true" primary="true">Microsoft</owner>
   6 // <owner current="true" primary="false">Microsoft</owner>
   7 //------------------------------------------------------------------------------
   8
   9 namespace System.Data.OleDb {
  10
  11     using System;
  12     using System.ComponentModel;
  13     using System.Data.Common;
  14     using System.Globalization;
  15     using System.Security;
  16     using System.Security.Permissions;
  17
  18     public sealed class OleDbEnumerator  {
  19
  20         public OleDbEnumerator() {
  21         }
  22
  23         public DataTable GetElements() {
  24             OleDbConnection.ExecutePermission.Demand();
  25
  26             DataTable dataTable = new DataTable("MSDAENUM"); // WebData 112482
  27             dataTable.Locale = CultureInfo.InvariantCulture;
  28             OleDbDataReader dataReader = GetRootEnumerator();
  29             OleDbDataAdapter.FillDataTable(dataReader, dataTable);
  30             return dataTable;
  31         }
  32
  33         static public OleDbDataReader GetEnumerator(Type type) {
  34             OleDbConnection.ExecutePermission.Demand();
  35
  36             return GetEnumeratorFromType(type);
  37         }
  38
  39         static internal OleDbDataReader GetEnumeratorFromType(Type type) { // WebData 99005
  40             // will demand security appropriately
  41             object value = Activator.CreateInstance(type, System.Reflection.BindingFlags.Public|System.Reflection.BindingFlags.Instance, null, null, CultureInfo.InvariantCulture, null);
  42             return GetEnumeratorReader(value);
  43         }
  44
  45         static private OleDbDataReader GetEnumeratorReader(object value) {
  46             NativeMethods.ISourcesRowset srcrowset = null;
  47
  48             try {
  49                 srcrowset = (NativeMethods.ISourcesRowset) value;
  50             }
  51             catch(InvalidCastException) {
  52                 throw ODB.ISourcesRowsetNotSupported();
  53             }
  54             if (null == srcrowset) {
  55                 throw ODB.ISourcesRowsetNotSupported();
  56             }
  57             value = null; // still held by ISourcesRowset, reused for IRowset
  58
  59             int propCount = 0;
  60             IntPtr propSets = ADP.PtrZero;
  61
  62             Bid.Trace("<oledb.ISourcesRowset.GetSourcesRowset|API|OLEDB> IID_IRowset\n");
  63             OleDbHResult hr = srcrowset.GetSourcesRowset(ADP.PtrZero, ODB.IID_IRowset, propCount, propSets, out value);
  64             Bid.Trace("<oledb.ISourcesRowset.GetSourcesRowset|API|OLEDB|RET> %08X{HRESULT}\n", hr);
  65
  66             Exception f = OleDbConnection.ProcessResults(hr, null, null);
  67             if (null != f) {
  68                 throw f;
  69             }
  70
  71             OleDbDataReader dataReader = new OleDbDataReader(null, null, 0, CommandBehavior.Default);
  72             dataReader.InitializeIRowset(value, ChapterHandle.DB_NULL_HCHAPTER, ADP.RecordsUnaffected);
  73             dataReader.BuildMetaInfo();
  74             dataReader.HasRowsRead();
  75             return dataReader;
  76         }
  77
  78         static public OleDbDataReader GetRootEnumerator() {
  79             OleDbConnection.ExecutePermission.Demand();
  80
  81             IntPtr hscp;
  82             Bid.ScopeEnter(out hscp, "<oledb.OleDbEnumerator.GetRootEnumerator|API>\n");
  83             try {
  84                 //readonly Guid CLSID_MSDAENUM = new Guid(0xc8b522d0,0x5cf3,0x11ce,0xad,0xe5,0x00,0xaa,0x00,0x44,0x77,0x3d);
  85                 //Type msdaenum = Type.GetTypeFromCLSID(CLSID_MSDAENUM, true);
  86                 const string PROGID_MSDAENUM = "MSDAENUM";
  87                 Type msdaenum = Type.GetTypeFromProgID(PROGID_MSDAENUM, true);
  88                 return GetEnumeratorFromType(msdaenum);
  89             }
  90             finally {
  91                 Bid.ScopeLeave(ref hscp);
  92             }
  93         }
  94     }
  95 }
  96