如果位数超过 5，则以科学记数法设置文本框输出的格式

Question

我对编程完全陌生，但昨天我设法用 VBA for Excel 编写了一个简单的转换计算器。由于代码并不真正需要Excel，我发现我想让它成为一个独立的应用程序并下载了Visual Basic。

在工作了一晚上将VBA for Excel代码迁移到Visual Basic之后，我终于设法使主要代码功能正常工作。

但是，如果位数超过 5，我想以科学记数法输出文本框1结果。我尝试直接使用VBA代码，虽然它没有导致错误，但它也没有改变任何东西。

这是我的 VBA 代码：

Private Sub CommandButton1_Click()
Dim rates(0 To 5, 0 To 5) As Double, i As Integer, j As Integer
rates(0, 0) = 1
rates(0, 1) = 86400
rates(0, 2) = 100
rates(0, 3) = 8640000
rates(0, 4) = 283460
rates(0, 5) = 2120428.8
rates(1, 0) = 0.000011574
rates(1, 1) = 1
rates(1, 2) = 0.0011574
rates(1, 3) = 100
rates(1, 4) = 3.2808
rates(1, 5) = 24.542
rates(2, 0) = 0.01
rates(2, 1) = 864
rates(2, 2) = 1
rates(2, 3) = 86400
rates(2, 4) = 2834.6
rates(2, 5) = 21204.288
rates(3, 0) = 0.00000011574
rates(3, 1) = 0.01
rates(3, 2) = 0.000011574
rates(3, 3) = 1
rates(3, 4) = 0.032808
rates(3, 5) = 0.24542
rates(4, 0) = 0.0000035278
rates(4, 1) = 0.3048
rates(4, 2) = 0.00035278
rates(4, 3) = 30.4805
rates(4, 4) = 1
rates(4, 5) = 7.4333
rates(5, 0) = 4.74600000000001E-07
rates(5, 1) = 4.10054400000001E-02
rates(5, 2) = 4.74600000000001E-05
rates(5, 3) = 4.10054400000001
rates(5, 4) = 0.134530116
rates(5, 5) = 1
For i = 0 To 5
    For j = 0 To 5
        If ListBox1.ListIndex = i And ListBox2.ListIndex = j Then TextBox2.Value = TextBox1.Value * rates(i, j)
    Next j
Next i
End Sub

Private Sub ListBox1_DblClick(ByVal Cancel As MSForms.ReturnBoolean)
    CommandButton1_Click
End Sub
Private Sub ListBox1_KeyDown(ByVal KeyCode As MSForms.ReturnInteger, ByVal Shift As Integer)
    If KeyCode = vbKeyReturn Then
        CommandButton1_Click
    End If
End Sub

Private Sub ListBox2_DblClick(ByVal Cancel As MSForms.ReturnBoolean)
    CommandButton1_Click
End Sub
Private Sub ListBox2_KeyDown(ByVal KeyCode As MSForms.ReturnInteger, ByVal Shift As Integer)
    If KeyCode = vbKeyReturn Then
        CommandButton1_Click
    End If
End Sub
Private Sub TextBox1_KeyDown(ByVal KeyCode As MSForms.ReturnInteger, ByVal Shift As Integer)
    If KeyCode = vbKeyReturn Then
        CommandButton1_Click
    End If
End Sub
Private Sub TextBox2_Change()
    If Len(TextBox2) > 5 Then
    TextBox2 = Format(TextBox2, "0.00E+00")
    End If
End Sub
Private Sub UserForm_Initialize()
With ListBox1
    .AddItem "m/s"
    .AddItem "m/dag"
    .AddItem "cm/s"
    .AddItem "cm/dag"
    .AddItem "ft/day"
    .AddItem "gpd/ft2"
End With
With ListBox2
    .AddItem "m/s"
    .AddItem "m/dag"
    .AddItem "cm/s"
    .AddItem "cm/dag"
    .AddItem "ft/day"
    .AddItem "gpd/ft2"
End With
ListBox1.ListIndex = 0
ListBox2.ListIndex = 2
TextBox1.Value = 1
TextBox2.Value = 100
End Sub

这是我的Visual Basic代码：

Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim rates(0 To 5, 0 To 5) As Double, i As Integer, j As Integer
    rates(0, 0) = 1
    rates(0, 1) = 86400
    rates(0, 2) = 100
    rates(0, 3) = 8640000
    rates(0, 4) = 283460
    rates(0, 5) = 2120428.8
    rates(1, 0) = 0.000011574
    rates(1, 1) = 1
    rates(1, 2) = 0.0011574
    rates(1, 3) = 100
    rates(1, 4) = 3.2808
    rates(1, 5) = 24.542
    rates(2, 0) = 0.01
    rates(2, 1) = 864
    rates(2, 2) = 1
    rates(2, 3) = 86400
    rates(2, 4) = 2834.6
    rates(2, 5) = 21204.288
    rates(3, 0) = 0.00000011574
    rates(3, 1) = 0.01
    rates(3, 2) = 0.000011574
    rates(3, 3) = 1
    rates(3, 4) = 0.032808
    rates(3, 5) = 0.24542
    rates(4, 0) = 0.0000035278
    rates(4, 1) = 0.3048
    rates(4, 2) = 0.00035278
    rates(4, 3) = 30.4805
    rates(4, 4) = 1
    rates(4, 5) = 7.4333
    rates(5, 0) = 0.000000474600000000001
    rates(5, 1) = 0.0410054400000001
    rates(5, 2) = 0.0000474600000000001
    rates(5, 3) = 4.10054400000001
    rates(5, 4) = 0.134530116
    rates(5, 5) = 1
    For i = 0 To 5
        For j = 0 To 5
            If FraEnhet.SelectedIndex = i And TilEnhet.SelectedIndex = j Then
                TextBox2.Text = TextBox1.Text * rates(i, j)
            End If
        Next j
    Next i
End Sub
Private Sub TextBox2_Change()
    If Len(TextBox2) > 5 Then
        TextBox2.Text = FormatNumber("0.00E+00")
    End If
End Sub
End Class

如果有人也可以提示我如何设置双击并输入关键事件，将不胜感激。

谢谢

Answer 1

这里有一些建议：

• 在Button1_Click()中，您不需要任何循环，只需：

  TextBox2.Text = TextBox1.Text * rates(FraEnhet.SelectedIndex, TilEnhet.SelectedIndex)
  

• 至于 TextBox2 格式问题，我会去：

  TextBox2.Text = Convert.ToDouble(TextBox2.Text).ToString("0.00E+00")
  

• 但我宁愿将其保留在Button1_Click()中，而不是保存在不同的事件处理程序中(TextBox2_TextChanged()

  (：

  TextBox2.Text = TextBox1.Text * rates(FraEnhet.SelectedIndex, TilEnhet.SelectedIndex)
  If Len(TextBox2.Text) > 5 Then TextBox2.Text = Convert.ToDouble(TextBox2.Text).ToString("0.00E+00")
  

• 最后，VBA UserForm_Initialize()转换为 VB.NET Form1_Load()

以上所有内容都给出了以下Form1.vb代码：

Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim rates(0 To 5, 0 To 5) As Double, i As Integer, j As Integer
        rates(0, 0) = 1
        rates(0, 1) = 86400
        rates(0, 2) = 100
        rates(0, 3) = 8640000
        rates(0, 4) = 283460
        rates(0, 5) = 2120428.8
        rates(1, 0) = 0.000011574
        rates(1, 1) = 1
        rates(1, 2) = 0.0011574
        rates(1, 3) = 100
        rates(1, 4) = 3.2808
        rates(1, 5) = 24.542
        rates(2, 0) = 0.01
        rates(2, 1) = 864
        rates(2, 2) = 1
        rates(2, 3) = 86400
        rates(2, 4) = 2834.6
        rates(2, 5) = 21204.288
        rates(3, 0) = 0.00000011574
        rates(3, 1) = 0.01
        rates(3, 2) = 0.000011574
        rates(3, 3) = 1
        rates(3, 4) = 0.032808
        rates(3, 5) = 0.24542
        rates(4, 0) = 0.0000035278
        rates(4, 1) = 0.3048
        rates(4, 2) = 0.00035278
        rates(4, 3) = 30.4805
        rates(4, 4) = 1
        rates(4, 5) = 7.4333
        rates(5, 0) = 0.000000474600000000001
        rates(5, 1) = 0.0410054400000001
        rates(5, 2) = 0.0000474600000000001
        rates(5, 3) = 4.10054400000001
        rates(5, 4) = 0.134530116
        rates(5, 5) = 1
        TextBox2.Text = TextBox1.Text * rates(FraEnhet.SelectedIndex, TilEnhet.SelectedIndex)
        If Len(TextBox2.Text) > 5 Then TextBox2.Text = Convert.ToDouble(TextBox2.Text).ToString("0.00E+00")
    End Sub
    'Private Sub TextBox2_TextChanged(sender As Object, e As EventArgs) Handles TextBox2.TextChanged
    '    If Len(TextBox2.Text) > 5 Then
    '        TextBox2.Text = Convert.ToDouble(TextBox2.Text).ToString("0.00E+00")
    '    End If
    'End Sub
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        With FraEnhet.Items
            .Add("m/s")
            .Add("m/dag")
            .Add("cm/s")
            .Add("cm/dag")
            .Add("ft/day")
            .Add("gpd/ft2")
        End With
        With TilEnhet.Items
            .Add("m/s")
            .Add("m/dag")
            .Add("cm/s")
            .Add("cm/dag")
            .Add("ft/day")
            .Add("gpd/ft2")
        End With
        FraEnhet.SelectedIndex = 0
        TilEnhet.SelectedIndex = 2
        TextBox1.Text = 1
        TextBox2.Text = 100
    End Sub
End Class

Answer 2

您可以使用

.ToString()方法输出科学概念。例如

    TextBox1.Text = (0.000000474600000000001).ToString("0.00E+00")
    ' OR
    TextBox1.Text = value.ToString("0.00E+00")

您可以在此处阅读有关自定义数字格式的更多信息

至于事件，您可以查看此内容(不是VB(，但会指出使用"闪电"图标选择要连接的事件的正确方向。或者你可以创建一个子来handles这样的事件

Private sub Textbox_changed() Handles TextBox1.TextChanged
 'Textbox change event
End sub