轉換字符串錯誤

Question

每當我嘗試運行我的節目，我不斷收到，「從字符串轉換‘59 60 65 75個國家

錯誤’鍵入‘雙師型’是無效的。」

我從一個名爲scores.txt的文件中獲取我的數據，該文件包含整數59,60,65,75。我不太清楚如何解決這個問題，VB已經提出了一些諸如確保該值小於無窮大（顯然是），並確保源類型轉換爲目標類型。（這個我是如何調試不確定）有什麼建議？這是我的代碼

Public Class Form1 

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnanalyze.Click 


     Dim scores() As String = 
      IO.File.ReadAllLines("scores.txt") 
     Dim intdata(scores.length - 1) As Double 'declare an array of type double to store the data of text file 

     Dim mean As Double 
     Dim sdeviation As Double = 0 
     For i As Integer = 0 To scores.length - 1 
      intdata(i) = CDbl(scores(i)) 

     Next 
     mean = intdata.Average 'mean is the average of the numbers in the collection 
     For j As Integer = 0 To intdata.Length - 1 
      sdeviation = +Math.Pow(intdata(j) - mean, 2) 

     Next 
     sdeviation = sdeviation/(intdata.Length) 
     sdeviation = Math.Sqrt(sdeviation) 
     lblmean.text = FormatNumber(mean) 
     lblsd.text = FormatNumber(sdeviation) 
     lblnumofexams.text = scores.length 
     Dim query = From score In scores 
        Let Sscore = score 
        Let grade = getGrade(score, mean, sdeviation) 
        Select Sscore, grade 
     dvgoutput.datasource = query.tolist 
     dvgoutput.currentcell = Nothing 
     dvgoutput.columns("Sscore").headertext = "score" 
     dvgoutput.columns("grade").headertext = "grade" 




    End Sub 
    Public Function getGrade(ByVal ES, ByVal m, ByVal s) As String 
     If ES >= m + (1.5 * s) Then 
      Return "A" 
     End If 
     If m + (0.5 * s) < +ES And ES < m + (1.5 * s) Then 
      Return "B" 
     End If 

     If m - (0.5 * s) <= ES And ES < m + (0.5 * s) Then 
      Return "C" 
     End If 

     If m - (1.5 * s) <= ES And ES < +m - (0.5 * s) Then 
      Return "D" 
     End If 

     If ES < m - (1.5 * s) Then 
      Return "F" 
     End If 
     Return "" 
    End Function 

End Class 

Answer 1

您需要在文本文件中每行有一個分數。