dbenumerator.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Data / System / Data / Common / dbenumerator.cs / 1305376 / dbenumerator.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
// [....]
//----------------------------------------------------------------------------- 
 
namespace System.Data.Common {
 
    using System;
    using System.Collections;
    using System.Data;
    using System.Data.ProviderBase; 
    using System.Diagnostics;
    using System.ComponentModel; 
 
    public class DbEnumerator : IEnumerator {
 
        internal IDataReader _reader;
        internal IDataRecord _current;
        internal SchemaInfo[] _schemaInfo; // shared schema info among all the data records
        internal PropertyDescriptorCollection _descriptors; // cached property descriptors 
        private FieldNameLookup _fieldNameLookup; // MDAC 69015
        private bool closeReader; 
 
        // users must get enumerators off of the datareader interfaces
        public DbEnumerator(IDataReader reader) { 
            if (null == reader) {
                throw ADP.ArgumentNull("reader");
            }
            _reader = reader; 
        }
 
        public DbEnumerator(IDataReader reader, bool closeReader) { // MDAC 68670 
            if (null == reader) {
                throw ADP.ArgumentNull("reader"); 
            }
            _reader = reader;
            this.closeReader = closeReader;
        } 

 
        public object Current { 
            get {
                return _current; 
            }
        }

        /*public IDataRecord Current { 
            get {
                return _current; 
            } 
        }*/
 
/*
        virtual internal IDataRecord NewRecord(SchemaInfo[] si, object[] values, PropertyDescriptorCollection descriptors) {
            return new DbDataRecord(si, values, descriptors);
        } 

        virtual internal void GetValues(object[] values) { 
            _reader.GetValues(values); 
        }
*/ 

        public bool MoveNext() {

            if (null == _schemaInfo) { 
                  BuildSchemaInfo();
            } 
 
            Debug.Assert(null != _schemaInfo && null != _descriptors, "unable to build schema information!");
            _current = null; 

            if (_reader.Read()) {
                // setup our current record
                object[] values = new object[_schemaInfo.Length]; 
                _reader.GetValues(values); // this.GetValues()
                _current = new DataRecordInternal(_schemaInfo, values, _descriptors, _fieldNameLookup); // this.NewRecord() 
                return true; 
            }
            if (closeReader) { 
                _reader.Close();
            }
            return false;
        } 

        [ EditorBrowsableAttribute(EditorBrowsableState.Never) ] // MDAC 69508 
        public void Reset() { 
            throw ADP.NotSupported();
        } 

        private void BuildSchemaInfo() {
            int count = _reader.FieldCount;
            string[] fieldnames = new string[count]; 
            for (int i = 0; i < count; ++i) {
                fieldnames[i] = _reader.GetName(i); 
            } 
            ADP.BuildSchemaTableInfoTableNames(fieldnames); // MDAC 71401
 
            SchemaInfo[] si = new SchemaInfo[count];
            PropertyDescriptor[] props = new PropertyDescriptor[_reader.FieldCount];
            for (int i = 0; i < si.Length; i++) {
                SchemaInfo s = new SchemaInfo(); 
                s.name = _reader.GetName(i);
                s.type = _reader.GetFieldType(i); 
                s.typeName = _reader.GetDataTypeName(i); 
                props[i] = new DbColumnDescriptor(i, fieldnames[i], s.type);
                si[i] = s; 
            }

            _schemaInfo = si;
            _fieldNameLookup = new FieldNameLookup(_reader, -1); // MDAC 71470 
            _descriptors = new PropertyDescriptorCollection(props);
        } 
 
        sealed private class DbColumnDescriptor : PropertyDescriptor {
            int _ordinal; 
            Type _type;

            internal DbColumnDescriptor(int ordinal, string name, Type type)
                : base(name, null) { 
                _ordinal = ordinal;
                _type = type; 
            } 

            public override Type ComponentType { 
                get {
                    return typeof(IDataRecord);
                }
            } 

            public override bool IsReadOnly { 
                get { 
                    return true;
                } 
            }

            public override Type PropertyType {
                get { 
                    return _type;
                } 
            } 

            public override bool CanResetValue(object component) { 
                return false;
            }

            public override object GetValue(object component) { 
                return ((IDataRecord)component)[_ordinal];
            } 
 
            public override void ResetValue(object component) {
                throw ADP.NotSupported(); 
            }

            public override void SetValue(object component, object value) {
                throw ADP.NotSupported(); 
            }
 
            public override bool ShouldSerializeValue(object component) { 
                return false;
            } 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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dbenumerator.cs source code in C# .NET

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