DataTable Transaction Logger

using System;
using System.Collections.Generic;
using System.Data;
using System.Windows.Forms;

using System.Reflection;

using Clifton.Tools.Data;
using MyXaml.Core;

namespace DataTableUndoRedo
{
	public class Program
	{
		protected DataTable dt;
		protected DataTableTransactionLog tlog;

		[MyXamlAutoInitialize]
		DataGrid dgTransactions = null;

		[MyXamlAutoInitialize]
		Button btnUndo = null;

		[MyXamlAutoInitialize]
		Button btnRedo = null;

		protected bool columnErrorOnChange;
		protected bool rowErrorOnChange;
		protected bool revertFieldValue;
		
		/// <summary>
		/// Gets/sets revertFieldValue
		/// </summary>
		public bool RevertFieldValue
		{
			get { return revertFieldValue; }
			set { revertFieldValue = value; }
		}
		
		/// <summary>
		/// Gets/sets rowErrorOnDelete
		/// </summary>
		public bool RowErrorOnChange
		{
			get { return rowErrorOnChange; }
			set { rowErrorOnChange = value; }
		}
		
		/// <summary>
		/// Gets/sets columnErrorOnChange
		/// </summary>
		public bool ColumnErrorOnChange
		{
			get { return columnErrorOnChange; }
			set { columnErrorOnChange = value; }
		}

		[STAThread]
		static void Main()
		{
			Application.EnableVisualStyles();
			Application.SetCompatibleTextRenderingDefault(false);
			new Program();
		}

		int undoRow = 0;

		public Program()
		{
			tlog = new DataTableTransactionLog();
			tlog.TransactionAdding += new DataTableTransactionLog.TransactionDlgt(OnTransactionAdding);
			tlog.TransactionAdded += new DataTableTransactionLog.TransactionDlgt(OnTransactionAdded);
			string names="Marc.Clifton,Karen.Linder,Ian.Clifton,Chris.Maunder,Anders.Molin,Tom.Archer,Justin.Dunlap,Bill.Sergio";
			dt = new DataTable();
			dt.Columns.Add(new DataColumn("LastName", typeof(string)));
			dt.Columns.Add(new DataColumn("FirstName", typeof(string)));

			string[] name = names.Split(',');
			int i = 0;

			foreach (string s in name)
			{
				string[] fl = s.Split('.');
				DataRow dr = dt.NewRow();
				dr["FirstName"] = fl[0];
				dr["LastName"] = fl[1];
				dt.Rows.Add(dr);
				++i;
			}

			// sync up.
			dt.AcceptChanges();

			DataView dv = new DataView(dt);
			dv.Sort = "LastName, FirstName";

			tlog.SourceTable = dt;

			// Add our validation event handlers after the transaction log event handlers, just for fun.
			dt.ColumnChanging += new DataColumnChangeEventHandler(OnColumnChanging);
			dt.RowChanging += new DataRowChangeEventHandler(OnRowChanging);

			Parser.AddExtender("MyXaml.WinForms", "MyXaml.WinForms", "WinFormExtender"); 
			Parser p = new Parser();
			p.AddReference("app", this);
			p.AddReference("view", dv);
			p.AddReference("transactions", tlog.Log);
			Form form = (Form)p.Instantiate("app.myxaml", "*");
			p.InitializeFields(this);

			btnUndo.Enabled = false;
			btnRedo.Enabled = false;

			// Test collecting uncommitted rows.
			//DataRow dr1 = dt.NewRow();
			//dr1["LastName"] = "Foo";
			//DataRow dr2 = dt.NewRow();
			//dr2["FirstName"] = "Bar";
			//tlog.CollectUncommittedRows();

			Application.Run(form);
		}

		void OnColumnChanging(object sender, DataColumnChangeEventArgs e)
		{
			if (columnErrorOnChange)
			{
				e.Row.SetColumnError(e.Column, "Column Error");

				if (revertFieldValue)
				{
					e.ProposedValue = e.Row[e.Column];
				}
			}
			else
			{
				e.Row.SetColumnError(e.Column, null);
			}
		}

		void OnRowChanging(object sender, DataRowChangeEventArgs e)
		{
			if (rowErrorOnChange)
			{
				e.Row.RowError = "Row Error";
			}
			else
			{
				e.Row.RowError = null;
			}
		}

		void OnTransactionAdding(object sender, TransactionEventArgs e)
		{
			btnRedo.Enabled = false;
			
			if (undoRow < tlog.Log.Count - 1)
			{
				tlog.Log.RemoveRange(undoRow + 1, tlog.Log.Count - (undoRow + 1));
				tlog.AcceptChanges();  // We have to accept changes at this point to sync the table.
			}
		}

		void OnTransactionAdded(object sender, TransactionEventArgs e)
		{
			dgTransactions.DataSource = null;
			dgTransactions.DataSource = tlog.Log;
			undoRow = tlog.Log.Count - 1;
			dgTransactions.CurrentRowIndex = undoRow;
			dgTransactions.Invalidate();
			btnUndo.Enabled = true;
		}

		void OnUndo(object sender, EventArgs e)
		{
			tlog.Revert(undoRow);
			--undoRow;

			if (undoRow < 0)
			{
				btnUndo.Enabled = false;
			}

			dgTransactions.CurrentRowIndex = undoRow;
			dgTransactions.Invalidate();
			btnRedo.Enabled = true;
		}

		void OnRedo(object sender, EventArgs e)
		{
			++undoRow;
			tlog.Apply(undoRow);

			if (undoRow == tlog.Log.Count - 1)
			{
				btnRedo.Enabled = false;
			}

			dgTransactions.CurrentRowIndex = undoRow;
			dgTransactions.Invalidate();
			btnUndo.Enabled = true;
		}

		void OnAcceptChanges(object sender, EventArgs e)
		{
			tlog.AcceptChanges();
		}

		void OnRejectChanges(object sender, EventArgs e)
		{
			// Redo any "undone" changes to sync the table with
			// the transaction log.
			while (undoRow < tlog.Log.Count - 1)
			{
				OnRedo(sender, e);
			}

			tlog.RejectChanges();
			dgTransactions.DataSource = null;
			dgTransactions.DataSource = tlog.Log;
			undoRow = tlog.Log.Count - 1;
			dgTransactions.CurrentRowIndex = undoRow;
			dgTransactions.Invalidate();
		}

		void OnClear(object sender, EventArgs e)
		{
			dt.Clear();
			dgTransactions.DataSource = null;
			dgTransactions.DataSource = tlog.Log;
		}

		void OnCollect(object sender, EventArgs e)
		{
			tlog.CollectUncommittedRows();
			dgTransactions.DataSource = null;
			dgTransactions.DataSource = tlog.Log;
			dgTransactions.CurrentRowIndex = tlog.Log.Count - 1;
			dgTransactions.Invalidate();
		}
	}
}