Added vNext versions of Data Readers

yuramag · May 19, 2017 · 4369334 · 4369334
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diff --git a/BulkInsertDemo/API/vNext/DynamicDataReader.cs b/BulkInsertDemo/API/vNext/DynamicDataReader.cs
@@ -0,0 +1,217 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Data;
+using System.Data.Common;
+using System.Linq;
+
+/*
+ * This version of DynamicDataReader is inherited from DbDataReader, but not IDataReader, 
+ * which is particularly useful in .NET Core, since it does not define IDataReader interface.
+ */
+
+namespace BulkInsertDemo.API.vNext
+{
+    public sealed class DynamicDataReader<T> : DbDataReader
+    {
+        private readonly IList<SchemaFieldDef> m_schema;
+        private readonly IDictionary<string, int> m_schemaMapping;
+        private readonly Func<T, string, object> m_selector;
+        private IEnumerator<T> m_dataEnumerator;
+
+        public DynamicDataReader(IList<SchemaFieldDef> schema, IEnumerable<T> data, Func<T, string, object> selector)
+        {
+            m_schema = schema;
+            m_schemaMapping = m_schema.Select((x, i) => new { x.FieldName, Index = i }).ToDictionary(x => x.FieldName, x => x.Index);
+            m_selector = selector;
+            m_dataEnumerator = data.GetEnumerator();
+        }
+
+        #region IDataReader Members
+
+        public override int Depth => 1;
+
+        public override bool IsClosed => m_dataEnumerator == null;
+
+        public override bool NextResult()
+        {
+            return false;
+        }
+
+        public override bool Read()
+        {
+            if (IsClosed)
+                throw new ObjectDisposedException(GetType().Name);
+            return m_dataEnumerator.MoveNext();
+        }
+
+        public override int RecordsAffected => -1;
+
+        public override IEnumerator GetEnumerator()
+        {
+            return m_dataEnumerator;
+        }
+
+        public override bool HasRows { get; } = true;
+
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                if (m_dataEnumerator != null)
+                {
+                    m_dataEnumerator.Dispose();
+                    m_dataEnumerator = null;
+                }
+            }
+        }
+
+        #endregion
+
+        #region IDataRecord Members
+
+        public override int FieldCount => m_schema.Count;
+
+        public override int GetOrdinal(string name)
+        {
+            int ordinal;
+            if (!m_schemaMapping.TryGetValue(name, out ordinal))
+                throw new InvalidOperationException("Unknown parameter name: " + name);
+            return ordinal;
+        }
+
+        public override object GetValue(int i)
+        {
+            if (m_dataEnumerator == null)
+                throw new ObjectDisposedException(GetType().Name);
+
+            var value = m_selector(m_dataEnumerator.Current, m_schema[i].FieldName);
+
+            if (value == null)
+                return DBNull.Value;
+
+            var strValue = value as string;
+            if (strValue != null)
+            {
+                if (strValue.Length > m_schema[i].Size && m_schema[i].Size > 0)
+                    strValue = strValue.Substring(0, m_schema[i].Size);
+                if (m_schema[i].DataType == DbType.String)
+                    return strValue;
+                return SchemaFieldDef.StringToTypedValue(strValue, m_schema[i].DataType) ?? DBNull.Value;
+            }
+
+            return value;
+        }
+
+        #region Not Implemented Members
+
+        public override bool GetBoolean(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override byte GetByte(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override long GetBytes(int ordinal, long dataOffset, byte[] buffer, int bufferOffset, int length)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override char GetChar(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override long GetChars(int ordinal, long dataOffset, char[] buffer, int bufferOffset, int length)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override string GetDataTypeName(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override DateTime GetDateTime(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override decimal GetDecimal(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override double GetDouble(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override Type GetFieldType(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override float GetFloat(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override Guid GetGuid(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override short GetInt16(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override int GetInt32(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override long GetInt64(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override string GetName(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override string GetString(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override int GetValues(object[] values)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override bool IsDBNull(int ordinal)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override object this[int ordinal]
+        {
+            get { throw new NotImplementedException(); }
+        }
+
+        public override object this[string name]
+        {
+            get { throw new NotImplementedException(); }
+        }
+
+        #endregion
+
+        #endregion
+    }
+}