WealthScript Techniques | Trading with Trendlines in the Strategy Monitor

Problem

Solution

1. Compile the first script.
2. Draw a Trendline
3. Name the Trendline Resistance
4. Click "Go" (or hit F5) to write the TL Resistance data to the file. (*This step is imperative!)
   

Code

using System;
using System.IO;
using System.Windows.Forms;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using WealthLab;
using WealthLab.Indicators;

namespace WealthLab.Strategies
{
	public class TrendlineDataToFile : WealthScript
	{
		public void AddStringToFile(string path, string str)
		{			
			string temp = String.Empty;
			
			if (File.Exists(path))
				using (StreamReader sr = new StreamReader(path))
				{
					temp = sr.ReadToEnd();
				}
						
			using (StreamWriter file = new StreamWriter(path, true))
			{
				if (!temp.Contains(str)) 
					file.WriteLine(str);
			}
		}
		
		public void RemoveKeyRecordFromFile(string path, string key)
		{			
			string temp = String.Empty;
			
			if (!File.Exists(path))	return;
				
			using (StreamReader sr = new StreamReader(path))
			{
				temp = sr.ReadToEnd();
			}
			
			string[] lines = temp.Split(new string[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
			if (!temp.Contains(key)) return;
			
			List<string> tlist = new List<string>();			
			using (StreamWriter file = new StreamWriter(path, false))
			{			
				foreach (string s in lines)
				{
					if (!s.Contains(key))
						tlist.Add(s);						
				}											
			}
			File.WriteAllLines(path, tlist);
		}
		
		protected override void Execute()
		{	
			string TLName = "Resistance";
			int b1 =  Bars.Count - 10;
			double st1 = TrendlineValue( b1, TLName );
			
			int b2 =  Bars.Count - 5;
			double st2 = TrendlineValue( b2, TLName );			
			double slope = (st2 - st1) / (b2 - b1);
			
			string key = String.Format("{0},{1},{2},{3}", Bars.Symbol, Bars.Scale, Bars.BarInterval, TLName);
			string s = key + String.Format(",{0},{1},{2}", Date[b2].ToString("yyyyMMdd"), st2, slope);			
			
			string path = Path.Combine(Application.UserAppDataPath, @"Data\MyTrendLineAlerts.txt"); 
			
			// Always remove a previous entry and refresh if required
			RemoveKeyRecordFromFile(path, key);	
			
			if (st2 != 0)  // edit: I removed  && slope != 0, since it's possible to draw a perfectly horizontal TL
			{				
				AddStringToFile(path, s);
			}
			else
			{				
				DrawLabel(PricePane, "Could not find Trendline named '" + TLName + "'", Color.Red);
			}
		}
	}
}

using System;
using System.IO;
using System.Windows.Forms;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using WealthLab;
using WealthLab.Indicators;

namespace WealthLab.Strategies
{
	public class MyStrategy : WealthScript
	{	
		protected override void Execute()
		{
			string TLName = "Resistance";
			
			string path = Path.Combine(Application.UserAppDataPath, @"Data\MyTrendLineAlerts.txt"); 
			
			if (!File.Exists(path))
			{				
				DrawLabel(PricePane, "Could not find MyTrendLineAlerts.txt", Color.Red);
				return;
			}
			
			string temp = String.Empty;
			using (StreamReader sr = new StreamReader(path))
			{
				temp = sr.ReadToEnd();
			}
					
			string key = String.Format("{0},{1},{2},{3}", Bars.Symbol, Bars.Scale, Bars.BarInterval, TLName);
			
			if (!temp.Contains(key))
			{				
				DrawLabel(PricePane, "Could not find Trendline '" + TLName + "' for this Symbol & Scale", Color.Red);
				return;
			}
			
			// Find the Trendline value for the last bar			 
			string[] lines = temp.Split(new string[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
			
			IFormatProvider format = new System.Globalization.CultureInfo("en-US");
			foreach (string s in lines)
			{
				if (s.Contains(key))		// found the trendline for this symbol and scale
				{							
					
					string[] data = s.Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries);
					//Index sample:
					//0    1      2  3          4        5       6
					//AAPL,Minute,30,Resistance,20140321,530.827,0.0794347826087687
					
					DateTime dte = DateTime.ParseExact(data[4], "yyyyMMdd", format);
					
					int b2 = DateTimeToBar(dte, true);
					if (b2 == -1)
					{				
						DrawLabel(PricePane, "Could not recreate Trendline '" + TLName + "' for current range", Color.Red);
						break;
					}					
					
					// Note that fbar is the NEXT future bar, so y is the value of the trendline 'tomorrow'
					int fbar = Bars.Count;		
					double y = Convert.ToDouble(data[6]) * (fbar - b2) + Convert.ToDouble(data[5]);
					
					BuyAtMarket(1);
					SellAtStop(fbar, LastPosition, y, data[3]);
					
					DrawLabel (PricePane, "TL Value is: " + y.ToString("0.000"));			
					break;	
				}
			}
			
		}
	}
}