Python解释器如何查找类型？(How does Python interpreter look for types?)

 - 更新---将此部分替换为下面提供的代码区域 
 
   Dim x2 As Integer = 0 ' Keep a track of index
   For Each i As Integer In ListBox1.Items
        ' create a Point with index as x and the actual value of list item as y
         s.Points.AddXY(Convert.toDouble(x2), Convert.toDouble(i))
         x2 = x2+1
   Next
 
 图表应该是这样的 
 
 Chart1.Series.Clear() 'Empty your chart of any previous values

 Chart1.Titles.Add("My Line chart") 'Add a Title

 Dim s As New Series 'Create a new series
 s.Name = "My Line" 'Series name

 s.ChartType = SeriesChartType.Line 'Chart type

 'Most important part, the points to plot
 'Points START
  s.Points.AddXY(1, 2)
  s.Points.AddXY(3, 4)
  s.Points.AddXY(5, 9)
 'Points END

 'Add the series to the Chart1 control
 Chart1.Series.Add(s)
 
 我不确定你为什么使用RichTextBox1。 如果你正在收集用户输入（x，y）点，那么你将需要构建你的点。 使用TextBox控件而不是RichText ，只要使用给定的描述就足够了。 
 
 用这个替换上面代码中的Points位 
 
'Assume the user is entering value/numbers separated by ","
'Use the input as both x and y
'e.g 1,2,3,...
Dim textCont As String = TextBox.Text
Dim boxValues As String() = textCont.Split(New Char() {","})
For Each item In boxValues
 s.Points.AddXY(Convert.toDouble(item), Convert.toDouble(item))
 s.Points.AddXY(Convert.toDouble(item), Convert.toDouble(item))
 s.Points.AddXY(Convert.toDouble(item), Convert.toDouble(item))
Next
 
 就您提供的代码而言，本示例中没有使用ListBox控件或引用。 
 
 AddXY（双人间，双人间） 

--Update--- Replace this part in the Points region of code provided below
 
   Dim x2 As Integer = 0 ' Keep a track of index
   For Each i As Integer In ListBox1.Items
        ' create a Point with index as x and the actual value of list item as y
         s.Points.AddXY(Convert.toDouble(x2), Convert.toDouble(i))
         x2 = x2+1
   Next
 
A chart should be something like this
 
 Chart1.Series.Clear() 'Empty your chart of any previous values

 Chart1.Titles.Add("My Line chart") 'Add a Title

 Dim s As New Series 'Create a new series
 s.Name = "My Line" 'Series name

 s.ChartType = SeriesChartType.Line 'Chart type

 'Most important part, the points to plot
 'Points START
  s.Points.AddXY(1, 2)
  s.Points.AddXY(3, 4)
  s.Points.AddXY(5, 9)
 'Points END

 'Add the series to the Chart1 control
 Chart1.Series.Add(s)
 
I'm not sure why you are using a RichTextBox1. If you are gathering user input (x,y) points then you will need to construct your points. Use a TextBox control instead of RichText, it should suffice, with the given description.
 
Replace the Points bit in the above code with this 
 
'Assume the user is entering value/numbers separated by ","
'Use the input as both x and y
'e.g 1,2,3,...
Dim textCont As String = TextBox.Text
Dim boxValues As String() = textCont.Split(New Char() {","})
For Each item In boxValues
 s.Points.AddXY(Convert.toDouble(item), Convert.toDouble(item))
 s.Points.AddXY(Convert.toDouble(item), Convert.toDouble(item))
 s.Points.AddXY(Convert.toDouble(item), Convert.toDouble(item))
Next
 
As far as the code you've provided, there is no ListBox control or reference to use in this example.
 
AddXY(Double,Double)