Question

嘿伙计们，我的程序遇到了这个崩溃的问题。

我正在尝试创建一个程序，通过输入其期初余额，信用额度，总费用和总积分来计算个人帐户余额。在这种情况下，我对总费用和总积分代码有特定问题。

我设置了一个消息框，如果“总费用”和“总信用额”框为空，则会显示“请输入......的数值”。问题是，当我运行它并输入空白时，消息显示然后程序崩溃。

崩溃后，程序会以黄色突出显示特定的转换代码（在这种情况下为decTotalCharges = Convert.ToDecimal(txtTotalCharges.Text))，错误显示为Input string was not in correct format。

发生了什么事，我把它转换成了正确的格式吗？（十进制到十进制？）。以下是我的代码的深入分析：

Public Class frmEndingBalance

'Declare module level variables
Dim mdecEndingBalance As Decimal
Dim mdecAllCharges As Decimal
Dim mdecAllCredits As Decimal
Dim mintCustomersOverLimit As Integer

Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
    'clears the form
    'clears the labels
    txtAccountNumber.Text = ""
    txtBeginningBalance.Text = ""
    txtTotalCharges.Text = ""
    txtTotalCredits.Text = ""
    txtCreditLimit.Text = ""
    lblEndingBalance.Text = ""
    lblCreditMessage.Text = ""
    lblAllCharges.Text = ""
    lblAllCredits.Text = ""
    lblCustomersOverLimit.Text = ""
    lblCreditMessage.Text = ""

    'clear the textboxes
    txtAccountNumber.Clear()
    txtBeginningBalance.Clear()
    txtTotalCredits.Clear()
    txtTotalCharges.Clear()
    txtCreditLimit.Clear()

    'clear module level variables
    mdecEndingBalance = 0
    mdecAllCharges = 0
    mdecAllCredits = 0
    mintCustomersOverLimit = 0
End Sub

Private Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click

    'Declare Variables
    Dim intAccountNumber As Integer
    Dim intBeginningBalance As Integer
    Dim decTotalCharges As Decimal
    Dim decTotalCredits As Decimal
    Dim decCreditLimit As Decimal
    Dim mdecEndingBalance As Decimal 'Beginning Balance + Charges - Credits()
    Dim decCreditMessage As Decimal

    'check for numeric
    If IsNumeric(txtAccountNumber.Text) = False Then 'value is not numeric
        MessageBox.Show("You can't enter anything blank!")
        Exit Sub
    End If

    'convert to a numeric data type
    intAccountNumber = Convert.ToInt32(txtAccountNumber.Text)

    'check for numeric
    If String.IsNullOrEmpty(txtBeginningBalance.Text) Then MessageBox.Show("Beginning Balance Cannot Be Blank!")

    'check for everything else
    If IsNumeric(txtBeginningBalance.Text) = False Then 'Value is not numeric
        MessageBox.Show("Please enter a numeric value for Beginning Balance!")
        Exit Sub
    End If
    'convert to a numeric data type
    intBeginningBalance = Convert.ToInt32(txtBeginningBalance.Text)

    'check for numeric
    If IsNumeric(txtTotalCharges.Text) = False Then 'value is not numeric
        MessageBox.Show("Please enter a numeric value for Total Charges!")
    End If

    'convert 
    decTotalCharges = Convert.ToDecimal(txtTotalCharges.Text)

    'check for 0 or positive
    If decTotalCharges < 0 Then
        MessageBox.Show("Please enter a positive value or zero for number of Total Charges!")
        Exit Sub
    End If

    'check for numeric
    If IsNumeric(txtTotalCredits.Text) = False Then 'value is not numeric 
        MessageBox.Show("Please enter a numeric value for Total Credits")
    End If

    'convert to a numeric data type
    decTotalCredits = Convert.ToDecimal(txtTotalCredits.Text)


    'check for 0 or positive
    If decTotalCredits < 0 Then
        MessageBox.Show("Please enter a positive value or zero for total credits!")
    End If

    'check numeric
    If IsNumeric(txtCreditLimit.Text) = False Then 'value is not numeric
        MessageBox.Show("Please enter a numeric value for the Credit Limit!")
    End If

    'convert to a numeric data type
    decCreditLimit = Convert.ToDecimal(txtCreditLimit.Text)


    'check for a 0 or positive
    If decCreditLimit < 0 Then
        MessageBox.Show("Please enter a positive value or zero for Credit Limit!")
    End If

    'check for customers over limit
    decCreditMessage = decCreditLimit - (mdecEndingBalance)

    'running totals
    mdecAllCharges += decTotalCharges
    mdecAllCredits += decTotalCredits

    'calculate Ending Balance
    mdecEndingBalance = Convert.ToDecimal(intBeginningBalance + decTotalCharges - (decTotalCredits))

    'display outputs
    lblEndingBalance.Text = mdecEndingBalance.ToString("c")
    lblAllCharges.Text = mdecAllCharges.ToString("c")
    lblAllCredits.Text = mdecAllCredits.ToString("c")
    lblCustomersOverLimit.Text = mintCustomersOverLimit.ToString("n0")
End Class

非常感谢任何帮助！

由于

Answer 1

你错过了退出Sub的测试

If IsNumeric(txtTotalCharges.Text) = False Then 'value is not numeric
 MessageBox.Show("Please enter a numeric value for Total Charges!")
End If

你也是在其他几个地方完成的（事实上，我们所有人都是这样做的:(）。值得用一些辅助方法或类似方法进行重构。

If IsValidDecimal(txtTotalCharges.Text, "Total Charges") 
  ' etc
End If

VB.net：输入字符串格式不正确？

1 个答案: