developer/Samples/NET 4.6/Samples for Parallel/NQueens/NQueens_VisualBasic/MainForm.vb

   1 '--------------------------------------------------------------------------
   2 '
   3 '  Copyright (c) Microsoft Corporation.  All rights reserved.
   4 '
   5 '  File: MainForm.vb
   6 '
   7 '--------------------------------------------------------------------------
   8
   9 Imports System.Threading
  10 Imports System.Threading.Tasks
  11 Imports System.Windows.Forms.DataVisualization.Charting
  12
  13 Public Class MainForm
  14
  15     Private _uiScheduler As TaskScheduler
  16     Private _serial As DataPoint
  17     Private _parallel As DataPoint
  18     Private _max As Double = 0
  19
  20     Private Sub MainForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
  21         _uiScheduler = TaskScheduler.FromCurrentSynchronizationContext()
  22         SetupPoints()
  23     End Sub
  24
  25     Private Sub SetupPoints()
  26         _serial = chart1.Series(0).Points(chart1.Series(0).Points.AddXY("Serial", 0.0))
  27         _parallel = chart1.Series(0).Points(chart1.Series(0).Points.AddXY("Parallel", 0.0))
  28         chart1.ChartAreas(0).AxisY.Minimum = 0.0
  29         chart1.ChartAreas(0).AxisY.Maximum = 10.0
  30         ClearPointValues()
  31         Invalidate()
  32     End Sub
  33
  34     Private Sub ClearPointValues()
  35         For Each Point In New DataPoint() {_serial, _parallel}
  36             With Point
  37                 .SetValueY(0)
  38                 .ToolTip = ""
  39                 .Label = ""
  40                 .Font = New System.Drawing.Font(Point.Font, System.Drawing.FontStyle.Bold)
  41             End With
  42
  43         Next
  44         chart1.Invalidate()
  45     End Sub
  46
  47
  48     Private Sub btnSolve_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSolve.Click
  49         Dim numQueens = 0
  50         If Int32.TryParse(cbNumQueens.Text, numQueens) = False Then Return
  51
  52         btnSolve.Enabled = False
  53         progressBar1.Visible = True
  54
  55         ClearPointValues()
  56         _max = 0
  57
  58         Task.Factory.StartNew(Sub()
  59                                   Dim elapsed As TimeSpan
  60
  61                                   elapsed = Time(Sub()
  62                                                      NQueensSolver.Sequential(numQueens)
  63                                                  End Sub)
  64                                   SetPoint(_serial, elapsed.TotalSeconds)
  65
  66                                   elapsed = Time(Sub()
  67                                                      NQueensSolver.Parallel(numQueens)
  68                                                  End Sub)
  69                                   SetPoint(_parallel, elapsed.TotalSeconds)
  70                               End Sub
  71         ).ContinueWith(Sub(t)
  72                            progressBar1.Visible = False
  73                            btnSolve.Enabled = True
  74                            If t.IsFaulted Then  MessageBox.Show(t.Exception.ToString())
  75                        End Sub, _uiScheduler)
  76     End Sub
  77
  78
  79     Private Sub SetPoint(ByVal point As DataPoint, ByVal seconds As Double)
  80         Task.Factory.StartNew(Sub()
  81                                   If seconds > _max Then
  82                                       _max = seconds
  83                                       chart1.ChartAreas(0).AxisY.Maximum = _max * 1.1
  84                                   End If
  85                                   point.SetValueY(seconds)
  86                                   point.ToolTip = seconds.ToString("F3")
  87                                   point.Label = String.Format("{0:F3} secs  ({1:F2}x)", seconds, (_max / seconds))
  88                                   chart1.Invalidate()
  89                               End Sub, CancellationToken.None, TaskCreationOptions.None, _uiScheduler)
  90     End Sub
  91
  92     Private Shared Function Time(ByVal action As Action) As TimeSpan
  93         Dim sw = Stopwatch.StartNew()
  94         action()
  95         Return sw.Elapsed
  96     End Function
  97 End Class