我正在尝试创建一个成绩计算器程序，我遇到了两个问题：
基本形式基本上是一个输入7个输入等级：
并且个人应该获得他们的数字等级，他们的字母等级和两个计数器的输出，这些计数器计算有多少人得到A's和F's。
例如，当我输入3个考试成绩时：82，87，91; Assignments: 94; Peer reviews: 100; programming language presentation: 90;和final project: 92,
我的最终数字成绩为253.90，字母成绩为F，但显然应该是A和数字89.90的字母成绩。
我的计数器也无法正常工作，因为它们没有显示count，但我觉得我把它放在正确的位置（显示输出）。我到底错在了什么？这是我的代码
Option Strict On
Public Class frmGradeCalculator
'declare Constants
Const EXAM1GRADE_WEIGHT As Decimal = 0.15D
Const EXAM2GRADE_WEIGHT As Decimal = 0.2D
Const EXAM3GRADE_WEIGHT As Decimal = 0.2D
Const HOMEWORKGRADE_WEIGHT As Decimal = 0.2D
Const HOMEWORKPEERREVIEW_WEIGHT As Decimal = 0.05D
Const LANGUAGEQUICKREFERENCE_WEIGHT As Decimal = 0.1D
Const FINALPROJECT_WEIGHT As Decimal = 0.1D
'Declare module variables
Dim mdecFinalNumericGrade As Decimal
Dim mstrFinalLetterGrade As String
Dim mintStudentsWithAs As Integer
Dim mintStudentsWithFs As Integer
Private Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click
'declare variables
Dim decExam1Grade As Decimal
Dim decExam2Grade As Decimal
Dim decExam3Grade As Decimal
Dim decHomeworkGrade As Decimal
Dim decPeerReviewGrade As Decimal
Dim decLanguageReferenceGrade As Decimal
Dim decFinalProjectGrade As Decimal
Dim decPercent As Decimal
'check for blanks
If (txtExam1Grade.Text) = "" Then
MessageBox.Show("You Can't Leave Exam 1 Blank")
Exit Sub
End If
'check for numeric
If IsNumeric(txtExam1Grade.Text) = False Then 'value is not numeric
MessageBox.Show("Please enter a numeric value for Exam 1!")
Exit Sub
End If
'check for blanks
If (txtExam2Grade.Text) = "" Then
MessageBox.Show("Please enter Exam 2!")
Exit Sub
End If
'check for everything else
If IsNumeric(txtExam2Grade.Text) = False Then 'Value is not numeric
MessageBox.Show("Please enter a numeric value for Exam 2!")
Exit Sub
End If
'check for blanks
If (txtExam3Grade.Text) = "" Then
MessageBox.Show("Please enter Exam 3!")
Exit Sub
End If
'check for numerics
If IsNumeric(txtExam3Grade.Text) = False Then
MessageBox.Show("Please enter a positive numeric value for Exam3!")
Exit Sub
End If
'check for blanks
If (txtHomeworkGrade.Text) = "" Then
MessageBox.Show("Please enter Homework Grade!")
Exit Sub
End If
'check for numerics
If IsNumeric(txtHomeworkGrade.Text) = False Then
MessageBox.Show("Please enter a numeric positive value for Homework Grade!")
Exit Sub
End If
'check for blanks
If (txtPeerReviewGrade.Text) = "" Then
MessageBox.Show("Please enter a Peer Review Grade!")
Exit Sub
End If
'check for numerics
If IsNumeric(txtPeerReviewGrade.Text) = False Then
MessageBox.Show("Please enter a numeric positive value for Peer Review Grade!")
Exit Sub
End If
'check for blanks
If (txtLanguageReferenceGrade.Text) = "" Then
MessageBox.Show("Please enter a Language Reference Grade!")
Exit Sub
End If
'check for numerics
If IsNumeric(txtLanguageReferenceGrade.Text) = False Then
MessageBox.Show("Please enter a numeric positive value for Language Reference Grade!")
Exit Sub
End If
'check for blanks
If (txtFinalProjectGrade.Text) = "" Then
MessageBox.Show("Please enter a Final Project Grade!")
Exit Sub
End If
'check for numerics
If IsNumeric(txtFinalProjectGrade.Text) = False Then
MessageBox.Show("Please enter a numeric positive value for Final Project Grade!")
Exit Sub
End If
'convert data types
decExam1Grade = Convert.ToDecimal(txtExam1Grade.Text)
decExam2Grade = Convert.ToDecimal(txtExam2Grade.Text)
decExam3Grade = Convert.ToDecimal(txtExam3Grade.Text)
decHomeworkGrade = Convert.ToDecimal(txtHomeworkGrade.Text)
decPeerReviewGrade = Convert.ToDecimal(txtPeerReviewGrade.Text)
decLanguageReferenceGrade = Convert.ToDecimal(txtLanguageReferenceGrade.Text)
decFinalProjectGrade = Convert.ToDecimal(txtFinalProjectGrade.Text)
mdecFinalNumericGrade = (decExam1Grade * EXAM1GRADE_WEIGHT) + _
(decExam2Grade * EXAM2GRADE_WEIGHT) + _
(decExam3Grade * EXAM3GRADE_WEIGHT) + _
(decHomeworkGrade * HOMEWORKGRADE_WEIGHT) + _
(decPeerReviewGrade * HOMEWORKPEERREVIEW_WEIGHT) + _
(decLanguageReferenceGrade + LANGUAGEQUICKREFERENCE_WEIGHT) + _
(decFinalProjectGrade + FINALPROJECT_WEIGHT)
'check for 0 or positive
If decExam1Grade < 0 Then
MessageBox.Show("Please enter a positive value or zero for Exam 1!")
Exit Sub
End If
'check for 0 or positive
If decExam2Grade < 0 Then
MessageBox.Show("Please enter a positive value or zero for Exam 2!")
Exit Sub
End If
'check for 0 or positive
If decExam3Grade < 0 Then
MessageBox.Show("Please enter a positive value or zero for Exam 3!")
Exit Sub
End If
'check for 0 or positive
If decHomeworkGrade < 0 Then
MessageBox.Show("Please enter a positive value or zero for Homework Grade!")
Exit Sub
End If
'check for 0 or positive
If decPeerReviewGrade < 0 Then
MessageBox.Show("Please enter a positive value or zero for Peer Review Grade!")
Exit Sub
End If
'check for 0 or positive
If decLanguageReferenceGrade < 0 Then
MessageBox.Show("Please enter a positive value or zero for Language Reference!")
Exit Sub
End If
'check for 0 or positive
If decFinalProjectGrade < 0 Then
MessageBox.Show("Please enter a positive value or zero for Final Project Grade!")
Exit Sub
End If
'make sure values are less than 100
If decExam1Grade > 100 Then
MessageBox.Show("Please enter a value thats 100 or less!")
End If
If decExam2Grade > 100 Then
MessageBox.Show("Please enter a value thats 100 or less!")
End If
If decExam3Grade > 100 Then
MessageBox.Show("Please enter a value thats 100 or less!")
End If
If decHomeworkGrade > 100 Then
MessageBox.Show("Please enter a value thats 100 or less!")
End If
If decPeerReviewGrade > 100 Then
MessageBox.Show("Please enter a value thats 100 or less!")
End If
If decLanguageReferenceGrade > 100 Then
MessageBox.Show("Please enter a value thats 100 or less!")
End If
If decFinalProjectGrade > 100 Then
MessageBox.Show("Please enter a value thats 100 or less!")
End If
'Determine grade per letter
Select Case decpercent
Case Is >= 89.5D
mstrFinalLetterGrade = "A"
mintStudentsWithAs += 1
Case Is >= 79.5D
mstrFinalLetterGrade = "B"
Case Is >= 69.5D
mstrFinalLetterGrade = "C"
Case Is >= 59.5D
mstrFinalLetterGrade = "D"
Case Else
mstrFinalLetterGrade = "F"
mintStudentsWithFs += 1
End Select
lblFinalLetterGrade.Text = mstrFinalLetterGrade
'display outputs
lblFinalNumericGrade.Text = mdecFinalNumericGrade.ToString("f2")
End Sub
Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
'clear the texboxes and labels
txtExam1Grade.Clear()
txtExam2Grade.Clear()
txtExam3Grade.Clear()
txtHomeworkGrade.Clear()
txtPeerReviewGrade.Clear()
txtLanguageReferenceGrade.Clear()
txtFinalProjectGrade.Clear()
lblFinalLetterGrade.Text = ""
lblFinalNumericGrade.Text = ""
'setcursor back to top textbox
txtExam1Grade.Focus()
End Sub
Private Sub btnReset_Click(ByVal sende As System.Object, ByVal e As System.EventArgs) Handles btnReset.Click
'reset module level variables
mdecFinalNumericGrade = 0
mstrFinalLetterGrade = ""
mintStudentsWithAs = 0
mintStudentsWithFs = 0
End Sub
Private Sub btnExit_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnExit.Click
'close the form
End
End Sub
Private Sub frmGradeCalculator_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
End Sub
End Class
答案 0 :(得分：1)
您的最终成绩总数是错误的，因为您没有将语言表达和最终项目乘以其权重，而是将权重加到得分上：
注意最后两个值的加法（而不是乘法）。总数是253.9。
将medcFinalNumericGrade的最后两个计算更改为：
(decLanguageReferenceGrade * LANGUAGEQUICKREFERENCE_WEIGHT) + _
(decFinalProjectGrade * FINALPROJECT_WEIGHT)
您将始终获得“F”，因为永远不会为decpercent分配值，因此会执行Else Case。指定decpercent值，或使用mdecFinalNumericGrade。
例如：
Select Case mdecFinalNumericGrade
而不是
Select Case decpercent
修复Select Case后，您的计数应该有效（除非您重置表单）。