Update mongodb

Src/Asp.NetCore2/MongoDb.Ado.data/MongoDbDataReader.cs

@@ -9,13 +9,13 @@ using System.Collections;
 namespace MongoDb.Ado.data
 {
  
-    public class MongoDbDataReader : DbDataReader
+    public class MongoDbIAsyncCursorDataReader : DbDataReader
     {
         private readonly IAsyncCursor<BsonDocument> _cursor;
         private IEnumerator<BsonDocument> _enumerator;
         private BsonDocument _current;
 
-        public MongoDbDataReader(IAsyncCursor<BsonDocument> cursor)
+        public MongoDbIAsyncCursorDataReader(IAsyncCursor<BsonDocument> cursor)
         {
             _cursor = cursor;
             _enumerator = cursor.ToEnumerable().GetEnumerator();
@@ -119,4 +119,111 @@ namespace MongoDb.Ado.data
         public override int Depth => 0;
     }
 
+    public class MongoDbBsonDocumentDataReader : DbDataReader
+    {
+        private readonly IEnumerator<BsonDocument> _enumerator;
+        private BsonDocument _current;
+
+        public MongoDbBsonDocumentDataReader(IEnumerable<BsonDocument> documents)
+        {
+            _enumerator = documents.GetEnumerator();
+        }
+
+        public override bool Read()
+        {
+            if (_enumerator.MoveNext())
+            {
+                _current = _enumerator.Current;
+                return true;
+            }
+            return false;
+        }
+
+        public override int FieldCount => _current?.ElementCount ?? 0;
+
+        public override int Depth => throw new NotImplementedException();
+
+        public override bool HasRows => true;
+        public override bool IsClosed => false;
+        public override int RecordsAffected => -1;
+        public override bool NextResult() => false;
+
+        public override object this[int ordinal] => GetValue(ordinal);
+        public override object this[string name] => GetValue(GetOrdinal(name));
+
+        // 下面这些可以根据需要进一步实现或抛异常
+        public override bool GetBoolean(int ordinal) => (bool)GetValue(ordinal);
+        public override byte GetByte(int ordinal) => (byte)GetValue(ordinal);
+        public override long GetBytes(int ordinal, long dataOffset, byte[] buffer, int bufferOffset, int length) => throw new NotSupportedException();
+        public override char GetChar(int ordinal) => (char)GetValue(ordinal);
+        public override long GetChars(int ordinal, long dataOffset, char[] buffer, int bufferOffset, int length) => throw new NotSupportedException();
+        public override string GetDataTypeName(int ordinal) => GetFieldType(ordinal).Name;
+        public override DateTime GetDateTime(int ordinal) => (DateTime)GetValue(ordinal);
+        public override decimal GetDecimal(int ordinal) => (decimal)GetValue(ordinal);
+        public override double GetDouble(int ordinal) => (double)GetValue(ordinal);
+        public override Type GetFieldType(int ordinal) => GetValue(ordinal)?.GetType() ?? typeof(object);
+        public override float GetFloat(int ordinal) => (float)GetValue(ordinal);
+        public override Guid GetGuid(int ordinal) => (Guid)GetValue(ordinal);
+        public override short GetInt16(int ordinal) => (short)GetValue(ordinal);
+        public override int GetInt32(int ordinal) => (int)GetValue(ordinal);
+        public override long GetInt64(int ordinal) => (long)GetValue(ordinal);
+        public override string GetString(int ordinal) => (string)GetValue(ordinal);
+
+        public override IEnumerator GetEnumerator()
+        {
+            throw new NotImplementedException();
+        }
+
+        public override int GetValues(object[] values)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override bool IsDBNull(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override string GetName(int ordinal)
+        {
+            var element = GetElementByOrdinal(ordinal);
+            return element.Name;
+        }
+
+        public override int GetOrdinal(string name)
+        {
+            int i = 0;
+            foreach (var elem in _current.Elements)
+            {
+                if (elem.Name.Equals(name, StringComparison.OrdinalIgnoreCase))
+                    return i;
+                i++;
+            }
+            throw new IndexOutOfRangeException($"Field '{name}' not found.");
+        }
+
+        public override object GetValue(int ordinal)
+        {
+            if (_current == null)
+                throw new InvalidOperationException("No current document.");
+
+            var element = GetElementByOrdinal(ordinal);
+            return BsonTypeMapper.MapToDotNetValue(element.Value);
+        }
+        private BsonElement GetElementByOrdinal(int ordinal)
+        {
+            if (_current == null)
+                throw new InvalidOperationException("No current document.");
+
+            int i = 0;
+            foreach (var elem in _current.Elements)
+            {
+                if (i == ordinal)
+                    return elem;
+                i++;
+            }
+            throw new IndexOutOfRangeException();
+        }
+    }
+
 }