tablemanager.cs

一个通用的数据库访问层

using System;
using System.Data;
using System.Data.OleDb;
using System.Windows.Forms;
using YariSoft.DBUtil;
//using Hargal;

namespace YariSoft.DBCommander
{
	public class TableManager : IManager
	{
		#region Local variables
		#endregion

		#region Properties
		#endregion

		#region Constructor/Destructor
		public TableManager( OleDbConnection Connecton, SchemaGenerator SchemaGenerator )
			: base ( Connecton, SchemaGenerator )
		{
		}

		public override void Dispose(){
		}
		#endregion

		#region Public functions
		public override DataView FillData( object SelectValue )
		{
			DataView result = null;
			string tableName = SelectValue.ToString().Trim();
			if( tableName == "" ){
				return result;
			}

			result = this.GetData( tableName );
			if( result != null ){
				return result;
			}

			if( !this.OpenConnection() ){
				return result;
			}
			try {
				
				YOleDbAdapter adapter = null;
				if( this.schema.Adapters.ContainsKey( tableName ) ){
					adapter = ( YOleDbAdapter )this.schema.Adapters[ tableName ];
				} else {
					adapter = this.PrepareDataAdapter ( tableName );
					this.schema.Adapters.Add( tableName, adapter );
				}
				
				adapter.DataAdapter.Fill( this.schema.Schema, tableName );
				result = this.schema.Schema.Tables[tableName].DefaultView;
				this.needRefresh = false;
			} catch(Exception Exp ) {
				YariSoft.Utils.YMessages.Show( Exp.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error );
				if( result != null ){
					result.Dispose();
				}
			}

			this.CloseConnection();
			return result;
		}

		public override DataView GetData( object SelectValue )
		{
			this.schema.Schema.Tables[SelectValue.ToString()].DefaultView.RowFilter = "";
			if( this.schema.Schema.Tables[SelectValue.ToString()].DefaultView.Count > 0 ){
				return this.schema.Schema.Tables[SelectValue.ToString()].DefaultView;
			}
			return null;
		}


		public override DataView RefreshData( object SelectValue )
		{
			DataView result = null;
			string tableName = SelectValue.ToString().Trim();
			if( tableName == "" ){
				return result;
			}

			if( this.schema.Schema.Tables[tableName] != null ){
				while( this.schema.Schema.Tables[tableName].Rows.Count < this.schema.Schema.Tables[tableName].DefaultView.Count ){
					this.schema.Schema.Tables[tableName].DefaultView.Delete( this.schema.Schema.Tables[tableName].DefaultView.Count - 1 );
				}
				this.schema.Schema.Tables[tableName].Clear();
			}

			return this.FillData( SelectValue ) ;
		}


		public override bool UpdateData( object UpdateObject )
		{
			bool result = true;
			if( (( DataTable )UpdateObject).GetChanges() == null ){
				return result;
			}
		
			YOleDbAdapter adapter = null;
			try{
				DataTable changes = (( DataTable )UpdateObject);
				if( changes == null ){
					return true;
				}
				adapter = ( YOleDbAdapter )this.schema.Adapters[(( DataTable )UpdateObject).TableName];
				if( adapter != null ){
					adapter.DataAdapter.Update( changes );
				}
			} catch( Exception Exp ) {
				result = false;
				if ( Exp is DBConcurrencyException && adapter != null ){
					result = YariSoft.DBUtil.Util.TryToSaveConcurrencyData ( ( DBConcurrencyException )Exp, adapter.DataAdapter );
				}
				if( !result ){
					YariSoft.Utils.YMessages.Show( Exp.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error );
				}
				(( DataTable )UpdateObject).RejectChanges();

				this.needRefresh = true;
			}

			return result;
		}

		public override bool FillTableDataByFK ( string FKName )
		{
			string childTableName = YariSoft.DBUtil.Util.GetTableNameByFK( FKName, this.schema.Schema );

			if( childTableName != "" ){
				if( this.schema.Schema.Tables[childTableName].Rows.Count > 0 ){
					return true;
				}
				this.FillData( childTableName );	
				return true;
			}
			return false;
		}
		#endregion

		#region Private functions
		private YOleDbAdapter PrepareDataAdapter ( string TableName )
		{
			OleDbDataAdapter dataAdapter = new System.Data.OleDb.OleDbDataAdapter( "SELECT * FROM "+ DBUtil.Util.GetTableName( TableName ), this.connecton );
			OleDbCommandBuilder commandBuilder = new OleDbCommandBuilder( dataAdapter );

			commandBuilder.QuotePrefix = "[";
			commandBuilder.QuoteSuffix = "]";
			return new YOleDbAdapter ( dataAdapter, commandBuilder );
		}

		private void OnListChanged(object sender, System.ComponentModel.ListChangedEventArgs args)
		{
			if( args.ListChangedType == System.ComponentModel.ListChangedType.ItemAdded ||
				args.ListChangedType == System.ComponentModel.ListChangedType.ItemChanged ||
				args.ListChangedType == System.ComponentModel.ListChangedType.ItemDeleted ){
				this.UpdateData( (( DataView )sender).Table );
			}
		}

		private void OnDataTableChanged(object sender, System.Data.DataRowChangeEventArgs e) 
		{ 
			this.UpdateData( sender );
		}

		#endregion
	}
}