VB textbox.enter 给出空值（累加器）

Question

我有一个简单的 VB 程序，通过 TextBox.Enter 累积失败。目标是：如何修复TextBox.Enter？我没有收到 MsgBox，表明尚未遵循操作树。

Option Explicit On
Public Class MainForm

Public decexpenses, decincome As Decimal
Public dectotalexpenses As Decimal = 0
Public dectotalincome As Decimal = 0

Private Sub MainForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    MsgBox("Use Enter key to enter values.")
End Sub

Private Sub expensesTextBox_Enter(sender As Object, e As EventArgs) Handles expensesTextBox.Enter
    Do Until expensesTextBox.Text = String.Empty
        Dim expenses = expensesTextBox.Text
        MsgBox(expenses) ' i dont get a msgbox for this indicating this value is null
        Do Until IsNumeric(expenses)
            MsgBox("Please enter numeric value for expenses.")
        Loop
        decexpenses = CDec(expenses)
        dectotalexpenses = decexpenses + dectotalexpenses
    Loop
End Sub

Private Sub incomeTextBox_Enter(sender As Object, e As EventArgs) Handles incomeTextBox.Enter
    Do Until incomeTextBox.Text = String.Empty
        Dim income = incomeTextBox.Text
        Do Until IsNumeric(income)
            MsgBox("Please enter numeric value for income.")
        Loop
        decincome = CDec(income)
        dectotalincome = decincome + dectotalexpenses
    Loop
End Sub

End Class

Answer 1

你就不能正确地使用一个方法来执行下面的操作吗？看起来您所做的一切都是为了检查以确保它是输入到文本框中的整数，如果它是计算它，否则显示一个消息框告诉用户输入一个数字。

 Private Sub expensesTextBox_Enter(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles expensesTextBox.KeyPress
    Dim dectotalexpenses As Decimal = 0
    Dim dectotalincome As Decimal = 0

    Dim income As String = expensesTextBox.Text

    If Keys.E + Keys.Enter Then


        If IsNumeric(income) = True Then
            dectotalincome = income + dectotalexpenses

        Else
            MessageBox.Show("Please Enter A Number")
        End If
    End If
End Sub

VB textbox.enter 给出空值（累加器）

VB textbox.enter gives null value (accumulator)

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enter