運行

Question

期間通過變量循環是有一種方法通過一組運行時間期間定義的變量的循環，而無需編寫的代碼來處理每個變量 例如控制檯應用程序的下面一行新代碼：

Module Module1 

    Sub Main() 
     Dim a!, b#, c%, d&, s$ 

     Console.WriteLine("a " & VarType(a).ToString) 
     Console.WriteLine("b " & VarType(b).ToString) 
     Console.WriteLine("c " & VarType(c).ToString) 
     Console.WriteLine("d " & VarType(d).ToString) 
     Console.WriteLine("s " & VarType(s).ToString) 
     Console.ReadLine() 
    End Sub 
End Module 

僞代碼將是這樣的：

for each Var in DefinedVariables 
'Do Something To the variable 
next 

Answer 1

正如我在評論中說，使用集合。例如

Dim letters As New List(Of String) From {"a", "b", "c", "d"} 

    For Each letter In letters 
     Console.WriteLine(letter) 
    Next 

編輯：

Dim a As String = "a" 
    Dim b As String = "b" 
    Dim c As String = "c" 
    Dim d As String = "d" 
    Dim e As Integer = 123 

    Dim variables As New List(Of Object) From {a, b, c, d, e} 

    For Each value In variables 
     Console.WriteLine(value.ToString) 
    Next 

Answer 2

您可以使用MethodBody.LocalVariables檢索方法體作爲LocalVariableInfo實例列表內聲明的局部變量。不幸的是，您只能通過索引訪問它們，因爲名稱未被存儲。你基本上得到變量類型，它被聲明的序號，以及它是否被固定。優化甚至可以重新排序變量或完全消除它們。

Dim mi As MethodInfo = GetType(Example).GetMethod("MethodBodyExample") 
Dim mb As MethodBody = mi.GetMethodBody() 
Console.WriteLine(vbCrLf & "Method: {0}", mi) 

' Display the general information included in the 
' MethodBody object. 
Console.WriteLine(" Local variables are initialized: {0}", mb.InitLocals) 
Console.WriteLine(" Maximum number of items on the operand stack: {0}", mb.MaxStackSize) 

' Display information about the local variables in the 
' method body. 
Console.WriteLine() 
For Each lvi As LocalVariableInfo In mb.LocalVariables 
    Console.WriteLine("Local variable: {0}", lvi) 
Next