private void StripButton_Start_Click(object sender, EventArgs e)
        { 
        // zgc means Zedgraph name,mypane means graph body         
            myPane = zgc.GraphPane;
            // Draw Curve 
            myCurve = myPane.AddCurve("", list, Color.Red, SymbolType.Circle);
            myCurve.Symbol.Size = 5.0F;
            myCurve.Symbol.Fill = new Fill(Color.Black);
            // Make up some data arrays based on the Sine function
            objstream = new StreamReader("E:\\temp.txt"); //Reading data from text file//
            
            // Generate a red curve with diamond
            // symbols, and "Porsche" in the legend
            zgc.ContextMenuBuilder += new ZedGraphControl.ContextMenuBuilderEventHandler(MyContextMenuBuilder);
            // Set the Y axis intersect the X axis at an X value of 0.0
            myPane.YAxis.Cross = 0.0;
            // Calculate the Axis Scale Ranges
            zgc.AxisChange();

                //Timer Enabled
                timer1.Enabled = true;
        }

private void timer1_Tick(object sender, EventArgs e)
        {
            GraphPane myPane = zgc.GraphPane;

            // Reading the Upto End of File
            while (!objstream.EndOfStream)
            {
                zgc.AxisChange();
                zgc.Refresh();
                zgc.BringToFront();
                str = objstream.ReadLine();
                tw.WriteLine(str+"\n");
                textBox.Text = str;
                string st = textBox6.Text;
object[] myColor ={ Color.Red, Color.Blue, Color.Yellow, Color.Green, Color.HotPink };
                myCurve = myPane.AddCurve("", list, (Color)myColor[i], SymbolType.Circle);
                if (str == "")
                {
//Here I new  graph Starts I want to change colors when new PointpairList start. How can i?
                    
                    list = new PointPairList();
                    myCurve = myPane.AddCurve("",list, Color.Blue, SymbolType.Circle);
                    myCurve.Symbol.Size = 5.0F;
                    myCurve.Symbol.Fill = new Fill(Color.Red);
                    str = objstream.ReadLine() + "\n";
                    i++;

                }
                    
                else
                {
                    string str1 = str.Substring(0, st.IndexOf("\t"));
                    string str2 = str.Substring(st.IndexOf("\t"));
                    x = (float)Convert.ToDecimal(str1);
                    y = (float)Convert.ToDecimal(str2);
                    list.Add(x, y);
                }
                
              }
            timer1.Stop();
            
        }