Common-VS2019/SacsStandardDbas/Dbas/Data/DbResultSet_DataTableReader.cs

using System;
using System.Data;
using System.Data.Common;
using Sarand.Net.Standard.Base.App;
using Sarand.Net.Standard.Base.Core;
using Sarand.Net.Standard.Base.Dbas;
using Sarand.Net.Standard.Dbas.Base;

namespace Sarand.Net.Standard.Dbas.Data
{
	//=======================================================================
	public class DbResultSet_DataTableReader : DbResultSet
	{
		//-------------------------------------------------------------------
		// Data members.
		private SacsDatabase database = null;
		private String query = String.Empty;
		private DbConnection dbConnection = null;
		private DbCommand dbCommand = null;
		private DbDataAdapter dbDataAdapter = null;
		private DataTableReader dataTableReader = null;
		//-------------------------------------------------------------------
		// Construction.
		public DbResultSet_DataTableReader (SacsDatabase database, String query)
		{
			this.database = database;
			this.query = query;
			ExecuteQuery();
		}
		//-------------------------------------------------------------------
		// Execute query.
		private void ExecuteQuery ()
		{
			ClearErrorState();
			String fn = GetType().Name + ".ExecuteQuery";
			Close();
			try
			{
				dbConnection = database.CreateConnection();
				dbCommand = dbConnection.CreateCommand();
				dbDataAdapter = database.CreateDataAdapter();
				dbDataAdapter.SelectCommand = dbCommand;
				dbDataAdapter.SelectCommand.CommandText = database.GetSelectQueryPrefix() + query;
				DataTable dataTable = new DataTable();
				dbDataAdapter.Fill(dataTable);
				dataTableReader = new DataTableReader(dataTable);
				Log(fn, GetType().Name + ".ExecuteQuery Query: " + query + (HasRows ? " [has rows]" : " [no rows]"), SaMessageLevel.Debug);
			}
			catch (Exception exc)
			{
				SetErrorState(exc.GetType().Name + ": " + exc.Message);
				SaLogger.Warn(fn + " " + exc.GetType().Name + ": " + exc.Message + "\n\t Query: " + query, true);
			}
		}
		//-------------------------------------------------------------------
		protected override void Dispose (bool disposing)
		{
			Close();
		}
		public override void Close ()
		{
			// Dispose of database objects.
			if (dataTableReader != null) dataTableReader.Close();
			dataTableReader = null;
			if (dbDataAdapter != null) dbDataAdapter.Dispose();
			if (dbCommand != null) dbCommand.Dispose();
			if (dbConnection != null) dbConnection.Dispose();
			dataTableReader = null;
			dbDataAdapter = null;
			dbCommand = null;
			dbConnection = null;
		}
		//-------------------------------------------------------------------
		// Navigation.
		public override bool NextRecord ()
		{
			// Move to next result.
			bool nextRecord = false;
			if (dataTableReader != null)
			{
				nextRecord = dataTableReader.Read();
				if (!nextRecord)
				{
					Close();
				}
			}
			return nextRecord;
		}
		//-------------------------------------------------------------------
		// Attributes.
		public override int FieldCount
		{
			get
			{
				if (dataTableReader != null)
					return dataTableReader.FieldCount;
				return 0;
			}
		}
		public override bool HasRows
		{
			get
			{
				if (dataTableReader != null)
					return dataTableReader.HasRows;
				return false;
			}
		}
		public override int GetOrdinal (String columnName)
		{
			if (dataTableReader != null)
				return dataTableReader.GetOrdinal(columnName);
			return -1;
		}
		public override String GetDataTypeName (int columnIdx)
		{
			if (dataTableReader != null)
				return dataTableReader.GetDataTypeName(columnIdx);
			return String.Empty;
		}
		public override String GetName (int columnIdx)
		{
			if (dataTableReader != null)
				return dataTableReader.GetName(columnIdx);
			return String.Empty;
		}
		public override bool IsDbNull (int columnIdx)
		{
			return (GetValue(columnIdx) is System.DBNull);
		}
		public override object GetValue (int columnIdx)
		{
			if (dataTableReader != null)
				return dataTableReader.GetValue(columnIdx);
			return false;
		}
		public override bool GetBoolean (int columnIdx)
		{
			if (dataTableReader != null)
				return dataTableReader.GetBoolean(columnIdx);
			return false;
		}
		public override byte GetByte (int columnIdx)
		{
			if (dataTableReader != null)
				return dataTableReader.GetByte(columnIdx);
			return 0;
		}
		public override short GetInt16 (int columnIdx)
		{
			if (dataTableReader != null)
				return dataTableReader.GetInt16(columnIdx);
			return 0;
		}
		public override int GetInt32 (int columnIdx)
		{
			if (dataTableReader != null)
				return dataTableReader.GetInt32(columnIdx);
			return 0;
		}
		public override long GetInt64 (int columnIdx)
		{
			if (dataTableReader != null)
				return dataTableReader.GetInt64(columnIdx);
			return 0;
		}
		public override float GetFloat (int columnIdx)
		{
			if (dataTableReader != null)
				return dataTableReader.GetFloat(columnIdx);
			return 0.0f;
		}
		public override double GetDouble (int columnIdx)
		{
			if (dataTableReader != null)
				return dataTableReader.GetDouble(columnIdx);
			return 0.0;
		}
		public override decimal GetDecimal (int columnIdx)
		{
			if (dataTableReader != null)
				return dataTableReader.GetDecimal(columnIdx);
			return 0.0m;
		}
		public override String GetString (int columnIdx)
		{
			if (dataTableReader != null)
				return dataTableReader.GetString(columnIdx);
			return String.Empty;
		}
		public override DateTime GetDateTime (int columnIdx)
		{
			if (dataTableReader != null)
				return dataTableReader.GetDateTime(columnIdx);
			return DateTime.MinValue;
		}
		//-------------------------------------------------------------------
	}
	//=======================================================================
}