Question

我的目标是这样做：将文件中的数据读入数组，加载列表框，计算每个学生的平均值并确定字母等级，并计算班级平均值：

我声明的变量（全局）：

Dim project，midterm，hw1，hw2，final，count，average As Integer

Dim letterGrade, lastName, firstName As String
Dim classAverage As Double

我的代码：

Dim array1 As String（）= New String（6）{}

    Dim streamreader1 As StreamReader = File.OpenText("grades.csv")
    count = 0
    classAverage = 0
    Do While (streamreader1.Peek() <> -1)
        array1 = Strings.Split(streamreader1.ReadLine(), ",", -1)
        firstName(count) = array1(0)
        lastName(count) = array1(1)
        lstNames.Items.Add(lastName(count) & ", " & firstName(count))
        hw1(count) = Convert.ToString(array1(2))
        hw2(count) = Convert.ToString(array1(3))
        project(count) = Convert.ToString(array1(4))
        midterm(count) = Convert.ToString(array1(5))
        final(count) = Convert.ToString(array1(6))
        average(count) = Math.Round(Math.Truncate((((((hw1(count) + hw2(count)) + (2 * project(count))) + (4 * (midterm(count) + final(count)))) / 12) + 0.5)))
        classAverage = (classAverage + ((((hw1(count) + hw2(count)) + (2 * project(count))) + (4 * (midterm(count) + final(count)))) / 12))
        Dim num1 As Integer = average(count)
        If (num1 >= 93) Then
            letterGrade(count) = "A"
        ElseIf (num1 >= 90) Then
            letterGrade(count) = "A-"
        ElseIf (num1 >= 87) Then
            letterGrade(count) = "B+"
        ElseIf (num1 >= 83) Then
            letterGrade(count) = "B"
        ElseIf (num1 >= 80) Then
            letterGrade(count) = "B-"
        ElseIf (num1 >= 77) Then
            letterGrade(count) = "C+"
        ElseIf (num1 >= 73) Then
            letterGrade(count) = "C"
        ElseIf (num1 >= 70) Then
            letterGrade(count) = "C-"
        ElseIf (num1 >= 67) Then
            letterGrade(count) = "D+"
        ElseIf (num1 >= 63) Then
            letterGrade(count) = "D"
        ElseIf (num1 >= 60) Then
            letterGrade(count) = "D"
        Else
            letterGrade(count) = "E"
        End If
        count = (count + 1)

    Loop
    classAverage = (classAverage / count)
    lstNames.SelectedIndex = 0
    PopulateLabels(0)
    streamreader1.Close()

Answer 1

看起来letterGrade是String，而不是字符串数组。您需要将其正确地声明为数组。

编辑后......

我建议创建一个Student类，其中包含文本文件中的值。它还包含针对对象本身执行的CalculateAverage()和CalculateLetterGrade()的方法。然后将文本文件中的每一行转储到Student对象中，并添加到List(Of Student)。获得此列表后，您可以遍历一个很好的简单对象列表来计算类平均值。

这样的事情：

Public Class Student
    Public FirstName As String
    Public LastName As String
    Public Project As Integer
    ...
    Public Final As Integer

    Public Function CalculateAverage() As Integer
        ... ' Your calculation function
    End Function

    Public Function CalculateLetterGrade() As String
        ... ' Your calculation function
    End Function
End Class

Dim students As New List(Of Student)

'Inside your loop:
    Dim student As New Student()
    student.Project = Convert.ToString(array1(4))
    ... ' etc.
    students.Add(student)

此时你将拥有一个简单的学生集合，你可以循环学习，计算你的班级平均水平或其他你需要的东西。

什么是＃34;属性字符是只读的＃34;在Visual Basic中，我该如何解决？

1 个答案: