从大型项目列表中创建位图的最快方法

Question

我目前正在创建一个班级项目列表

Public glstBeamsList As New List(Of BEAMLAYOUT)

Public Class BEAMLAYOUT
    Public sourceLocation(2) As Double
    Public pointEastingNorthingDepth As New List(Of Double())
End Class

此类列表项最多可包含256个点，数组中有3个项目。

我的问题是glstBeamsList不断被添加到，并且我通过列表读取的例程将点绘制到位图，并且一旦列表变大，在屏幕上显示需要很长时间。

这是我正在使用的代码，感谢任何帮助。

    Dim Eastlimit, WestLimit, NorthLimit, SouthLimit As Double
    Eastlimit = dblSourceLocationEastings + (gintPlanWidth / 2)
    WestLimit = dblSourceLocationEastings - (gintPlanWidth / 2)
    NorthLimit = dblSourceLocationNorthings + (gintPlanHeight / 2)
    SouthLimit = dblSourceLocationNorthings - (gintPlanHeight / 2)

    For i = 0 To glstBeamsList.Count - 1
        If glstBeamsList(i).sourceLocation(0) = 0 Or
           glstBeamsList(i).sourceLocation(1) = 0 Then GoTo nextPoint

        For ii = 0 To glstBeamsList(i).pointEastingNorthingDepth.Count - 1
            Dim point() = glstBeamsList(i).pointEastingNorthingDepth(ii)
            If point(0) < Eastlimit Then
                If point(0) > WestLimit Then
                    If point(1) < NorthLimit Then
                        If point(1) > SouthLimit Then
                            Dim x, y As Double
                            If point(0) < glstBeamsList(i).sourceLocation(0) Then x = point(0) - glstBeamsList(i).sourceLocation(0)
                            If point(0) > glstBeamsList(i).sourceLocation(0) Then x = glstBeamsList(i).sourceLocation(0) - point(0)
                            If point(1) < glstBeamsList(i).sourceLocation(1) Then y = point(1) - glstBeamsList(i).sourceLocation(1)
                            If point(1) > glstBeamsList(i).sourceLocation(1) Then y = glstBeamsList(i).sourceLocation(1) - point(1)
                            Dim clrPointColor As New Color
                            Select Case point(2)
                                Case -10 To 0
                                    clrPointColor = Color.Red
                                Case -20 To -11
                                    clrPointColor = Color.Orange
                                Case -30 To -21
                                    clrPointColor = Color.Yellow
                                Case -40 To -31
                                    clrPointColor = Color.Green
                                Case -50 To -41
                                    clrPointColor = Color.Blue
                                Case -60 To -51
                                    clrPointColor = Color.Indigo
                                Case -70 To -61
                                    clrPointColor = Color.Purple
                                Case -80 To -71
                                    clrPointColor = Color.Violet
                                Case -90 To -81
                                    clrPointColor = Color.Gray
                                Case -100 To -91
                                    clrPointColor = Color.Black
                                Case -110 To -101
                                    clrPointColor = Color.Red
                            End Select
                            Dim xLoc As Integer = ((gintPlanWidth / 2) + x) * gsngPlanScaleFactor
                            Dim yLoc As Integer = ((gintPlanHeight / 2) + y) * gsngPlanScaleFactor
                            If xLoc > 0 And xLoc < PicBox.Width Then
                                If yLoc > 0 And yLoc < PicBox.Height Then
                                    ggfxPlanViewBitmap.SetPixel(xLoc, yLoc, clrPointColor)

                                End If
                            End If
                        End If
                    End If
                End If
            End If
        Next