Question

我有一个Case语句，根据所选的情况返回不同数量的零。我需要一种方法，如果零的数量大于3，则修剪掉字符串中的最后3个零。我目前有返回字符串的情况，如＆＃34; 0＆＃34;或＆＃34; 000000＆＃34;。在那种情况下，代码将转为＆＃34; 000000＆＃34;进入＆＃34; 000＆＃34;。

我目前有：

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

但显然，这不起作用。任何帮助将不胜感激！

编辑：如果有人可以改进这篇文章，请做。应评论的要求，这是有问题的案例。

    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

需要考虑的一些事项：

表示条带的类将大大缩短代码：

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数据源属性将填充它。

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获取值很简单，只需将其转换回条带对象即可：

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

由于您将需要代码用于电阻器上的不同频段，因此您的代码将更加简洁。

Answer 2

首先，在Case结构中返回不同数量的零听起来有点奇怪，为什么不为不同的条件使用不同的数字或位标志呢？

NumberOfZeros.length是SO-msg中的拼写错误，还是实际代码？不应该是NumberOfZeros.Length吗？

根据条件修剪字符串中的最后3个字符

2 个答案: