Question

我有这个作为我的“长度”的转换程序，我怎么能用最简单的方式来做，而不是保持if，elseif，否则太多，我没有太多经验并试图提高我的编程技巧视觉工作室2008。

基本上，我对公式感到恼火，因为我不知道它是否正确，我使用谷歌但没有帮助，因为我不知道如何在程序从类型转换为类型时正确。

Public Class Form2
    Dim Metres As Integer
    Dim Centimetres As Integer
    Dim Inches As Integer
    Dim Feet As Integer
    Dim Total As Integer

    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        ErrorMsg.Hide()
    End Sub

    Private Sub btnConvert_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnConvert.Click

        Metres = 1
        Centimetres = 0.01
        Inches = 0.0254
        Feet = 0.3048

        txtTo.Text = 0

        If txtFrom.Text <> "" Then
            If IsNumeric(txtFrom.Text) And IsNumeric(txtTo.Text) Then

                If cbFrom.Text = "Metres" And cbTo.Text = "Centimetres" Then
                    Total = txtFrom.Text * Metres
                    txtTo.Text = Total
                ElseIf cbFrom.Text = "Metres" And cbTo.Text = "Inches" Then
                    Total = txtFrom.Text * 100
                    txtTo.Text = Total
                ElseIf cbFrom.Text = "Metres" And cbTo.Text = "Feet" Then

                ElseIf cbFrom.Text = "Centimetres" And cbTo.Text = "Metres" Then

                ElseIf cbFrom.Text = "Centimetres" And cbTo.Text = "Inches" Then

                ElseIf cbFrom.Text = "Centimetres" And cbTo.Text = "Feet" Then

                ElseIf cbFrom.Text = "Inches" And cbTo.Text = "Metres" Then

                ElseIf cbFrom.Text = "Inches" And cbTo.Text = "Centimetres" Then

                ElseIf cbFrom.Text = "Inches" And cbTo.Text = "Feet" Then

                ElseIf cbFrom.Text = "Feet" And cbTo.Text = "Metres" Then

                ElseIf cbFrom.Text = "Feet" And cbTo.Text = "Centimetres" Then

                ElseIf cbFrom.Text = "Feet" And cbTo.Text = "Inches" Then

                End If

            End If
        End If
    End Sub
End Class

这是我目前所做的事情的来源。

Answer 1

一种基本方法是通过使用中间格式来分割“从” - 和“到”转换的处理。

所以程序代码类似于这样：

Dim intermediate as Double //Intermediate format in centimeters
Dim result as Double
Dim inputValue as Double = cDbl(txtFrom.Text)

If cbFrom.Text = "Metres" Then
   intermediate = inputValue  * 100
else if cbFrom.Text = "Centimetres" Then
   intermediate = inputValue  
else if 
   ...
End If

If cbTo.Text = "Metres" Then
  result = intermediate / 100
else if cbTo.Text = "Centimetres" Then
  result = intermediate
End If 

txtTo.Text = Math.Round(result, 2) //Round optional :)

使用这种方法，您只需担心转换到中间格式和从中间格式转换，您只需处理一次输入和输出格式（而不是为每个输入/输出对编写自定义转换）。

Visual Studio转换套件

1 个答案: