case 语句为 true，但不执行 true case 条件下的代码

Question

我有一个应用程序，里面有组合框。在这些组合框中，我希望单位自动填充。我已经构建了一个有select..case条件的代码。case语句为 true，但不执行 true case 语句后面的代码。我通过断点分析了它，它也True显示它，但它没有执行并跳到最后。请指教。

Private Sub Load_units_combo_boxes()
Dim ComboBoxes As New ArrayList
For Each ComboBox In Me.Controls
If ComboBox.Name.Contains("Units") And TypeOf ComboBox Is ComboBox Then
ComboBoxes.Add(ComboBox)
End If
Next
For Each ComboBox In ComboBoxes
Select Case ComboBox.name.ToString
Case ComboBox.name.ToString.Contains("Pressure")
For Each unit In _units
If unit.contains("Pressure") Then
unit.replace("Pressure", "")
ComboBox.items.add(unit)
End If
Next
Case ComboBox.name.ToString.Contains("Distance")
For Each unit In _units
If unit.contains("Distance") Then
unit.replace("Distance", "")
ComboBox.items.add(unit)
End If
Next
End Select
Next
End Sub
Public _units As New ArrayList
Private Sub units_collection()
Dim units As New Units_and_conversions
Dim properties = units.GetType().GetProperties()
For Each prop In properties
_units.Add(prop.Name)
Next

End Sub
Public Class Units_and_conversions
Private universal_distance_unit As Double = 1
Private universal_pressure_unite As Double = 1

Public Property Distance_Meter() As Double
Get
Return universal_distance_unit
End Get
Set(value As Double)
value = universal_distance_unit
End Set
End Property
Public Property Distance_MilliMeter() As Double
Get
Return 0.001 * universal_distance_unit
End Get
Set(value As Double)
value = 0.001 * universal_distance_unit
End Set
End Property

结束类

Answer 1

此代码失败。

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles 
Button1.Click
Dim s As String = "abcdefghijklmnopqrstuvwxyz"
Select Case s
Case s.Contains("g")
MsgBox("Case Select Fails")
End Select
If s.Contains("g") Then
MsgBox("If statement works")
End If
End Sub

"案例选择"未设置为布尔问题，因此失败。以下代码将起作用。

此代码有效

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles 
Button1.Click
Dim s As String = "abcdefghijklmnopqrstuvwxyz"
Select Case True
Case s.Contains("g")
MsgBox("Case Select Works")
End Select
If s.Contains("g") Then
MsgBox("If statement works")
End If
End Sub

此代码之所以有效，是因为问题已正确设置为布尔问题而不是字符串比较。