根据条件修剪字符串的后3个字符

Question

我有一个Case语句，根据选择的大小写返回不同数量的零。 我需要一种方法，如果零的数量大于3，则修剪掉字符串的最后3个零。 我目前有返回“ 0”或“ 000000”之类的字符串的情况。 在这种情况下，代码会将“ 000000”变成“ 000”。

我目前有：

If NumberOfZeros.Length > 3 Then  
    NumberOfZeros.Remove(0, NumberOfZeros.Length - 3)  
End If

但是显然，这是行不通的。 任何帮助将不胜感激！

编辑：如果有人可以完善此职位，请这样做。 应评论要求，这里是有问题的案例。

    Dim Colour As String = " "
    Colour = Cmbl3.SelectedItem

    Select Case Colour
        Case "Black"
            NumberOfZeros = "0"
            lblcolour3.BackColor = Color.Black
            Cmbr.Enabled = True
        Case "Brown"
            NumberOfZeros = "00"
            lblcolour3.BackColor = Color.SaddleBrown
            Cmbr.Enabled = True
        Case "Red"
            ValueOf0s = "000"
            lblcolour3.BackColor = Color.Red
            Cmbr.Enabled = True
        Case "Orange"
            NumberOfZeros = "0000"
            lblcolour3.BackColor = Color.Orange
            Cmbr.Enabled = True
        Case "Yellow"
            NumberOfZeros = "00000"
            lblcolour3.BackColor = Color.Yellow
            Cmbr.Enabled = True
        Case "Green"
            ValueOf0s = "000000"
            lblcolour3.BackColor = Color.Green
            Cmbr.Enabled = True
        Case "Blue"
            NumberOfZeros = "0000000"
            lblcolour3.BackColor = Color.Blue
            Cmbr.Enabled = True
        Case "Violet"
            NumberOfZeros = "00000000"
            lblcolour3.BackColor = Color.DarkViolet
            Cmbr.Enabled = True
        Case "Grey"
            NumberOfZeros = "000000000"
            lblcolour3.BackColor = Color.Gray
            Cmbr.Enabled = True
        Case "White"
            NumberOfZeros = "0000000000"
            lblcolour3.BackColor = Color.White
            Cmbr.Enabled = True

        Case Else
            MsgBox("You must enter a colour choice from the third option box!")

    End Select 

            If NumberOfZeros.length > 3 Then
                NumberOfZeros.Remove(0, NumberOfZeros.Length - 3)
            End If
End Sub 

Answer 1

要考虑的一些事情：

代表条纹的类将大大简化代码：

Public Class Stripe
    Public colour As Color
    Public value As Int64
    Public name As String
    Sub New(_colour As Color, _value As Int64, _name As String)
        colour = _colour
        value = _value
        name = _name
    End Sub
    Public Overrides Function ToString() As String
        Return name
    End Function
End Class

创建此类的列表并将其分配给组合框的datasource属性将填充它。

Public stripes As New List(Of Stripe)
Public Sub New()

    ' This call is required by the designer.
    InitializeComponent()

    ' Add any initialization after the InitializeComponent() call.
    stripes.AddRange(
        {
        New Stripe(Color.Black, 1, "Black"),
        New Stripe(Color.Brown, 10, "Brown"),
        New Stripe(Color.Red, 100, "Red"),
        New Stripe(Color.Orange, 1000, "Orange"),
        New Stripe(Color.Yellow, 10000, "Yellow"),
        New Stripe(Color.Green, 100000, "Green"),
        New Stripe(Color.Blue, 1000000, "Blue"),
        New Stripe(Color.DarkViolet, 10000000, "Violet"),
        New Stripe(Color.Gray, 100000000, "Grey"),
        New Stripe(Color.White, 1000000000, "White")
        })
    cmbl3.DataSource = stripes
End Sub

现在，从selecteditem获取值是将其转换回条纹对象的简单问题：

Private Sub cmbl3_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cmbl3.SelectedIndexChanged
    Dim selectedStripe As Stripe = DirectCast(cmbl3.SelectedItem, Stripe)
    lblcolour3.BackColor = selectedStripe.colour
    'This assumes you have a label named lblvalue3 to display the value
    If selectedStripe.value < 1000 Then
        lblvalue3.Text = selectedStripe.value.ToString
    Else
        lblvalue3.Text = (selectedStripe.value / 1000).ToString & "K"
    End If
End Sub

由于您将需要针对电阻器上不同频段的代码，因此代码将变得更加简洁。

Answer 2

首先，在该Case结构中返回不同数量的零听起来有点奇怪，为什么不针对不同的条件使用不同的数字或位标记呢？

NumberOfZeros.length是SO-msg中的错字还是实际代码？ 它不是NumberOfZeros.Length吗？