Question

我是否通过TextBox.Enter累积的简单VB程序失败。目标是：如何修复TextBox.Enter？我没有得到MsgBox，表明没有遵循动作树。

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

难道你不能正确地执行下面的方法吗？看起来你要检查的是确保它是一个输入到文本框中的整数，如果是计算它，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null值（累加器）

1 个答案: