.net 如何写入数组并执行计算

我在一个.txt文件中编写了以下代码，该文件有三个等级，逗号由10行分隔。（每一行看起来像这样，94，57，84，）这段代码在文件中写起来很好，但我不知道如何使它平均分数。我肯定需要它来平均30分，是放在一个文本框，但我想它平均每行以及。我的GUI在我手动运行程序时执行此操作，但在我拉入生成的文本文件时不执行此操作。这是我的密码。第一部分是我编写的代码，第二部分是我所有的代码。谢谢你的建议

这是本书中的代码。我所做的只是添加了两个按钮，并在最后为这两个按钮编写了代码。我还将导入系统IO添加到类之前，并将dim filename的公共dim语句作为字符串添加。它将在没有差异的情况下写入，但当我调用submitbutton时，它在“grades（studentCount，0）=Concert.toInt32（test1TestBox.Text）处出现错误，因此我只从底部添加了数组代码行3,4,5。这使我的平均计算值为“0”。下面是本书中的代码，除了显示和打开按钮代码之外

       Imports System.IO ' using classes from this namespace

Public Class GradeReport
Dim fileName As String ' name of file containing account data
Dim grades(9, 2) As Integer ' stores 10 students' grades on 3 tests
Dim studentCount As Integer = 0 ' number of students entered

' display heading in gradeListBox
Private Sub GradeReport_Load(sender As Object,
   e As EventArgs) Handles MyBase.Load
    ' headings row for gradesListBox
    gradesListBox.Items.Add(vbTab & vbTab & "Test 1" & vbTab &
       "Test 2" & vbTab & "Test 3" & vbTab & "Average")
End Sub

' process one student's grades
Private Sub submitButton_Click(sender As Object,
   e As EventArgs) Handles submitButton.Click

    ' retrieve the student's grades
    grades(studentCount, 0) = Convert.ToInt32(test1TextBox.Text)
    grades(studentCount, 1) = Convert.ToInt32(test2TextBox.Text)
    grades(studentCount, 2) = Convert.ToInt32(test3TextBox.Text)

    ' begin creating String containing the student's grades and average
    Dim output As String = "Student " & studentCount & vbTab

    ' append each test grade to the output
    For column = 0 To grades.GetUpperBound(1)
        ' if the Letter RadioButton is checked
        If letterRadioButton.Checked = True Then
            ' append letter grade to the output
            output &= vbTab & LetterGrade(grades(studentCount, column))
        Else
            ' append number grade to the output
            output &= vbTab & grades(studentCount, column)
        End If
    Next

    ' append the student's test average to the output
    output &= vbTab & CalculateStudentAverage(studentCount)

    gradesListBox.Items.Add(output) ' add output to the ListBox
    studentCount += 1 ' update number of students entered
    averageLabel.Text = CalculateClassAverage() ' display class average
    DisplayBarChart() ' display the current grade distribution

    ' clear the input TextBoxes and set focus to first TextBox
    test1TextBox.Clear()
    test2TextBox.Clear()
    test3TextBox.Clear()
    test1TextBox.Focus()

    ' limit number of students
    If studentCount = grades.GetUpperBound(0) + 1 Then
        inputGradesGroupBox.Enabled = False ' disable GroupBox's controls
    End If
End Sub ' submitButton_Click

' handles Numeric and Letter RadioButtons' CheckChanged events
Private Sub RadioButton_CheckedChanged(sender As Object,
   e As EventArgs) _
   Handles numericRadioButton.CheckedChanged,
      letterRadioButton.CheckedChanged

    ' if there are grades to display, call DisplayClassGrades
    If studentCount > 0 Then
        DisplayClassGrades()
    End If
End Sub ' RadioButton_CheckedChanged

' calculates a student's test average
Function CalculateStudentAverage(row As Integer) As String
    Dim gradeTotal As Integer = 0 ' student's total grade

    ' sum the grades for the student
    For column = 0 To grades.GetUpperBound(1)
        gradeTotal += grades(row, column)
    Next

    Dim studentAverage As String = String.Empty ' output string

    ' calculate the student's test average
    If letterRadioButton.Checked = True Then
        studentAverage =
           LetterGrade(gradeTotal / (grades.GetUpperBound(1) + 1))
    Else
        studentAverage = String.Format("{0:F}",
           (gradeTotal / (grades.GetUpperBound(1) + 1)))
    End If

    Return studentAverage ' return the student's average
End Function ' CalculateStudentAverage

' calculates the class average
Function CalculateClassAverage() As String
    Dim classTotal As Integer = 0 ' class's total grade

    ' loop through all rows that currently contain grades
    For row = 0 To studentCount - 1
        ' loop through all columns
        For column = 0 To grades.GetUpperBound(1)
            classTotal += grades(row, column) ' add grade to total
        Next column
    Next row

    Dim classAverage As String = String.Empty ' output string

    ' if the Letter RadioButton is checked, return letter grade
    If letterRadioButton.Checked = True Then
        classAverage = LetterGrade(classTotal /
           (studentCount * (grades.GetUpperBound(1) + 1)))
    Else ' return numeric grade
        classAverage = String.Format("{0:F}", (classTotal /
           (studentCount * (grades.GetUpperBound(1) + 1))))
    End If

    Return classAverage ' return the class average
End Function ' CalculateClassAverage

' determines a letter grade corresponding to a numeric grade
Function LetterGrade(grade As Double) As String
    Dim output As String ' the letter grade to return

    ' determine the correct letter grade
    Select Case grade
        Case Is >= 90
            output = "A"
        Case Is >= 80
            output = "B"
        Case Is >= 70
            output = "C"
        Case Is >= 60
            output = "D"
        Case Else
            output = "F"
    End Select

    Return output ' return the letter grade
End Function ' LetterGrade

' display the grades for all students entered
Sub DisplayClassGrades()
    gradesListBox.Items.Clear() ' clear the ListBox

    ' add the header to the ListBox
    gradesListBox.Items.Add(vbTab & vbTab & "Test 1" & vbTab &
       "Test 2" & vbTab & "Test 3" & vbTab & "Average")

    ' loop through all the rows
    For row = 0 To studentCount - 1
        Dim output As String = "Student " & row & vbTab

        ' loop through all the columns
        For column = 0 To grades.GetUpperBound(1)
            If letterRadioButton.Checked = True Then
                ' add letter grade to output string
                output &= vbTab & LetterGrade(grades(row, column))
            Else
                ' add number grade to output string
                output &= vbTab & (grades(row, column))
            End If
        Next column

        ' add the student's average to the output
        output &= vbTab & CalculateStudentAverage(row)

        ' add the output to the ListBox
        gradesListBox.Items.Add(output)
    Next row

    ' update the class average
    averageLabel.Text = CalculateClassAverage()
End Sub ' DisplayClassGrades

' display a bar chart of the grade distribution
Sub DisplayBarChart()
    barChartListBox.Items.Clear() ' remove current items

    ' stores frequency of grades in each range of 10 grades
    Dim frequency(10) As Integer

    ' for each grade, increment the appropriate frequency
    For row = 0 To studentCount - 1
        For column = 0 To grades.GetUpperBound(1)
            frequency(grades(row, column) \ 10) += 1
        Next column
    Next row

    ' for each grade frequency, display bar of asterisks
    For count = 0 To frequency.GetUpperBound(0)
        Dim bar As String ' stores the label and bar

        ' create bar label ( "00-09: ", ..., "90-99: ", "100: " )
        If count = 10 Then
            bar = String.Format("{0, 5:D}: ", 100)
        Else
            bar = String.Format("{0, 2:D2}-{1, 2:D2}: ",
               count * 10, count * 10 + 9)
        End If

        ' append bar of asterisks
        For stars = 1 To frequency(count)
            bar &= ("*")
        Next

        barChartListBox.Items.Add(bar) ' display bar
    Next count
End Sub ' DisplayBarChart

Private Sub Open_Click(sender As Object, e As EventArgs) Handles Open.Click

    ' opens a file in which accounts are stored

    Dim result As DialogResult ' stores result of Open dialog

    ' create dialog box enabling user to open file
    Using fileChooser As New OpenFileDialog()
        result = fileChooser.ShowDialog()
        fileName = fileChooser.FileName ' get specified file name
    End Using ' automatic call to fileChooser.Dispose() occurs here

    ' if user did not click Cancel, enable Buttons
    If result <> Windows.Forms.DialogResult.Cancel Then
        Display.Enabled = True

    End If
End Sub ' OpenToolStripMenuItem_Click


Private Sub Display_Click(sender As Object, e As EventArgs) Handles Display.Click

    ' display accounts of specified type

    Dim fileReader As StreamReader = Nothing

    ' read and display file information
    Try
        gradesListBox.Text = "The accounts are:" & vbCrLf

        ' open file for reading
        fileReader = New StreamReader(fileName)

        ' read file and display lines that match the balance type
        Do While Not fileReader.EndOfStream ' while not end of file
            Dim line As String = fileReader.ReadLine() ' read line
            Dim fields() As String = line.Split(","c) ' split into fields
            'Dim fields() As String = line.Split(CChar(","))

            ' get data from fields array

            Dim Test1 As String = fields(0)             'Integer = Convert.ToInt32(fields(0))
            Dim Test2 As String = fields(1)
            Dim Test3 As String = fields(2)

            ' If ShouldDisplay(balance, accountType) Then
            gradesListBox.Items.Add(vbTab & vbTab & Test1 & vbTab &
               Test2 & vbTab & Test3 & vbCrLf)

        Loop
    Catch ex As IOException
        MessageBox.Show("Cannot Read File", "Error",
           MessageBoxButtons.OK, MessageBoxIcon.Error)
    Finally ' ensure that file gets closed
        If fileReader IsNot Nothing Then
            Try
                fileReader.Close() ' close StreamReader
            Catch ex As IOException
                MessageBox.Show("Error closing file", "Error",
                   MessageBoxButtons.OK, MessageBoxIcon.Error)
            End Try
        End If
    End Try


    ' submitButton.PerformClick


    studentCount += 1 ' update number of students entered
    averageLabel.Text = CalculateClassAverage() ' display class average
    DisplayBarChart() ' display the current grade distribution



End Sub ' submitButton_Click

使用来自此命名空间的类导入System.IO'
公开课成绩报告
Dim fileName作为包含帐户数据的文件的字符串名称
将分数（9,2）作为整数“存储10名学生在3次测试中的分数”
Dim studentCount为整数=0'输入的学生数
'在分级列表框中显示标题
私有子等级报告加载（发送者作为对象，
e作为EventArgs）处理MyBase.Load
'成绩列表框的标题行
gradesListBox.Items.Add（vbTab和vbTab&“测试1”和vbTab&
“测试2”&vbTab和“测试3”&vbTab和“平均值”）
端接头
“处理一名学生的成绩
私有子提交按钮单击（发送者作为对象，
e作为事件参数）处理submitButton。单击
'检索学生的成绩
成绩（studentCount，0）=转换为32（test1TextBox.Text）
成绩（studentCount，1）=转换为32（test2TextBox.Text）
成绩（学生人数，2）=转换为32（test3TextBox.Text）
'开始创建包含学生成绩和平均成绩的字符串
将输出设置为String=“Student”&studentCount&vbTab
'将每个测试等级附加到输出
对于列=0到坡度。GetUpperBound（1）
'如果选中了字母单选按钮
如果letterRadioButton.Checked=True，则
'将字母级别附加到输出
输出&=vbTab和LetterGrade（成绩（学生人数，列））
其他的
'将数字等级附加到输出
输出&=vbTab和成绩（学生人数，列）
如果结束
下一个
'将学生的测试平均值附加到输出
输出&=vbTab&CalculateStudentAverage（studentCount）
gradesListBox.Items.Add（输出）'将输出添加到列表框
studentCount+=1'更新输入的学生数
averageLabel.Text=CalculateClassAverage（）'显示类平均值
DisplayBarChart（）'显示当前等级分布
'清除输入文本框并将焦点设置为第一个文本框
test1TextBox.Clear（）
test2TextBox.Clear（）
test3TextBox.Clear（）
test1TextBox.Focus（）
“限制学生人数
如果studentCount=grades.GetUpperBound（0）+1，则
inputGradesGroupBox.Enabled=False“禁用GroupBox的控件
如果结束
结束子“提交”按钮单击
“处理数字和字母单选按钮”CheckChanged事件
私用子单选按钮\u CheckedChanged（发送者作为对象，
e作为事件参数）_
处理numericRadioButton.CheckedChanged，
letterRadioButton.CheckedChanged
'如果要显示等级，请调用DisplayClassGrades
如果studentCount>0，则
DisplayClassGrades（）
如果结束
“结束子”单选按钮已选中已更改
'计算学生的平均考试成绩
函数将culatestudentaverage（行作为整数）计算为字符串
Dim gradeTotal为整数=0'学生的总成绩
“给学生加总分数
对于列=0到坡度。GetUpperBound（1）
成绩合计+=成绩（行、列）
下一个
Dim studentAverage As String=String.Empty“输出字符串
'计算学生的平均考试成绩
如果letterRadioButton.Checked=True，则
学生平均=
字母等级（总等级/（等级.上界（1）+1））
其他的
studentAverage=String.Format（“{0:F}”，
（gradeTotal/（grades.GetUpperBound（1）+1）））
如果结束
Return studentAverage'返回学生的平均值
结束函数“CalculateStudentAverage”
'计算班级平均数
函数CalculateClassAverage（）作为字符串
Dim classTotal作为整数=0'类的总成绩
'循环浏览当前包含等级的所有行
对于行=0到studentCount-1
'循环遍历所有列
对于列=0到坡度。GetUpperBound（1）
classTotal+=等级（行、列）'将等级添加到总等级
下一栏
下一排
Dim classAverage As String=String.Empty“输出字符串
'如果选中字母单选按钮，则返回字母等级
如果letterRadioButton.Checked=True，则
类别平均=字母等级（类别总数）/
（学生人数*（grades.GetUpperBound（1）+1）））
Else返回数值等级
classAverage=String.Format（“{0:F}”，（classTotal）/
（学生人数*（grades.GetUpperBound（1）+1）））
如果结束
Return classAverage'返回类平均值
结束函数“计算平均值”
'确定与数字等级相对应的字母等级
函数LetterGrade（级别为双精度）作为字符串
将输出设置为字符串“要返回的字母等级”
'确定正确的字母等级
选择案例等级
案例>=90
输出=“A”
案例>=80
输出=“B”
案例>=70
输出=“C”
案例>=60
输出=“D”
其他情况
输出=“F”
EN
Private Sub Display_Click(sender As Object, e As EventArgs) Handles Display.Click

    ' display accounts of specified type

    Dim fileReader As StreamReader = Nothing

    ' read and display file information
    Try
        gradesListBox.Text = "The accounts are:" & vbCrLf

        ' open file for reading
        fileReader = New StreamReader(fileName)

        ' read file and display lines that match the balance type
        Dim Counter As Integer = 0
        Do While Not fileReader.EndOfStream ' while not end of file
            Dim line As String = fileReader.ReadLine() ' read line
            Dim fields() As String = line.Split(","c) ' split into fields
            'Dim fields() As String = line.Split(CChar(","))

            ' get data from fields array

            For I = 0 To 2
                Grades(Counter,I) = Integer.Parse(fields(I))
            Next


            ' If ShouldDisplay(balance, accountType) Then
            gradesListBox.Items.Add(vbTab & vbTab & Grades(Counter,0) & vbTab &
               Grades(Counter,1) & vbTab & Grades(Counter,2) & vbCrLf)
            If Counter <= 8 Then
                 Counter += 1
            Else
               Exit Do
            End If
        Loop
    Catch ex As IOException
        MessageBox.Show("Cannot Read File", "Error",
           MessageBoxButtons.OK, MessageBoxIcon.Error)
    Finally ' ensure that file gets closed
        If fileReader IsNot Nothing Then
            Try
                fileReader.Close() ' close StreamReader
            Catch ex As IOException
                MessageBox.Show("Error closing file", "Error",
                   MessageBoxButtons.OK, MessageBoxIcon.Error)
            End Try
        End If
    End Try


    ' submitButton.PerformClick


    studentCount += 1 ' update number of students entered
    averageLabel.Text = CalculateClassAverage() ' display class average
    DisplayBarChart() ' display the current grade distribution



End Sub ' submitButton_Click