如何在没有单击按钮的情况下在文本框中显示和的值 [英] How to show the value of sum in Textbox without click Button

问题描述

大家好，我想再问一遍。

Hi guys, i would like to ask more again.

我有两个Textbox和一个Combobox。文本框名称是txStay和txPay，Combobox的名称是txChoice

I have two Textbox and one Combobox. Textbox name's are txStay and txPay, name's of Combobox is txChoice

在Combobox内部有很多案例当我点击其中一个时，它会显示如下值：

Inside Combobox there's a lot of case that when I click one of them, it will show the value like this :

        Select Case cbChoice.SelectedItem
            Case "VIP"
                txPay.Text = "750,000"
            Case "Kelas I"
                txPay.Text = "500,000"
            Case "Kelas II"
                txPay.Text = "300,000"
            Case "Kelas III"
                txPay.Text = "150,000"
        End Select

然后当我将文本框'txStay'的值添加为Integer时，我想显示"<"的值txStay * txChoice"在'txPay'里面

Then when I add value of textbox 'txStay' as Integer, I want to show the value of "txStay * txChoice" inside 'txPay'

txChoice和txPay读为Double，所以我可以格式化为Double

That txChoice and txPay read as Double so I can format as Double

请给我任何结果？我很欣赏......

Any result, please? I'm so appreciate that...

谢谢

问候，

Aga

推荐答案

您好

非常混乱。

您正在进行一些不正确的编码，您可以根据自身和另一个文本框值设置文本框文本。

You are heading for a bad bit of coding where you are setting a textbox text with a value based on itself and another textbox value.

这就是你想要的，但前面有麻烦。

Here is what you say you want, but trouble ahead.

' Form1 with txChoice, txPay and txStay
Option Strict On
Option Explicit On
Public Class Form1
  Dim temp As Double = 0D
  Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    With txChoice
      .Items.Add("VIP")
      .Items.Add("Kelas I")
      .Items.Add("Kelas II")
      .Items.Add("Kelas III")
    End With
  End Sub
  Private Sub txChoice_SelectedIndexChanged(sender As Object, e As EventArgs) Handles txChoice.SelectedIndexChanged
    Dim cb As ComboBox = DirectCast(sender, ComboBox)
    Select Case cb.SelectedItem.ToString
      Case "VIP"
        txPay.Text = "750,000"
      Case "Kelas I"
        txPay.Text = "500,000"
      Case "Kelas II"
        txPay.Text = "300,000"
      Case "Kelas III"
        txPay.Text = "150,000"
    End Select
  End Sub
  Function Getdouble(s As String) As Double
    Dim v As Double = 0D
    If Double.TryParse(s, v) Then Return v
    Return 0D
  End Function
  Private Sub txStay_TextChanged(sender As Object, e As EventArgs) Handles txStay.Validated
    ' first, store the value before overwriting it.
    temp = Getdouble(txPay.Text)

    ' now calculate and overwrite.
    txPay.Text = (temp * Getdouble(txStay.Text)).ToString
  End Sub
End Class

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