LocalVariableInfo Class
Assembly: mscorlib (in mscorlib.dll)
To get a list of local variables in a method, use the LocalVariables property of the MethodBody class. Use the GetMethodBody method to obtain the MethodBody for a MethodInfo object.
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| Local variable names are not persisted in metadata. In Microsoft intermediate language (MSIL), local variables are accessed by their position in the local variable signature. |
The following code example defines a test method named MethodBodyExample, and displays its local variable information. The MethodBase.GetMethodBody method is used to obtain a MethodBody object for the test method. The MethodBody.LocalVariables property is then used to obtain a list of LocalVariableInfo objects and display their types and index order.
This code example is part of a larger example provided for the MethodBody class.
Imports System Imports System.Reflection Public Class Example Public Shared Sub Main() ' Demonstrate the effect of the Visual Basic When keyword, which ' generates a Filter clause in the Try block. Dim e As New Example() Console.WriteLine() e.MethodBodyExample("String argument") e.MethodBodyExample(Nothing) ' Get method body information. 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 ... End Sub ' This test method is executed at the beginning of Main, to show ' how the Filter clause works. The Filter clause is generated by ' a Visual Basic When expression. If arg is Nothing, this method ' throws ArgumentNullException, which is caught by the filter ' clause. If arg is a string, the method throws ArgumentException, ' which does not match the filter clause. ' ' Sub Main also contains code to analyze this method, using ' the properties and methods of the MethodBody class. Public Sub MethodBodyExample(ByVal arg As Object) ' Define some local variables. In addition to these variables, ' the local variable list includes the variables scoped to ' the catch clauses. Dim var1 As Integer = 42 Dim var2 As String = "Forty-two" Try ' Depending on the input value, throw an ArgumentException or ' an ArgumentNullException to test the Catch clauses. ' If arg Is Nothing Then Throw New ArgumentNullException("The argument cannot be Nothing.") End If If arg.GetType() Is GetType(String) Then Throw New ArgumentException("The argument cannot be a string.") End If ' The When expression makes this a filter clause. The expression ' selects only exceptions that derive from the ArgumentException ' class. Other exceptions, including ArgumentException itself, ' are not handled by this filter clause. Catch ex As ArgumentException _ When ex.GetType().IsSubclassOf(GetType(ArgumentException)) Console.WriteLine("Filter clause caught: {0}", ex.GetType()) ' This catch clause handles the ArgumentException class, and ' any other class derived from Exception. Catch ex As Exception Console.WriteLine("Ordinary exception-handling clause caught: {0}", _ ex.GetType()) Finally var1 = 3033 var2 = "Another string." End Try End Sub End Class ' This code example produces output similar to the following: ' 'Ordinary exception-handling clause caught: System.ArgumentException 'Filter clause caught: System.ArgumentNullException ' 'Method: Void MethodBodyExample(System.Object) ' Local variables are initialized: True ' Maximum number of items on the operand stack: 3 ... ' 'Local variable: System.Int32 (0) 'Local variable: System.String (1) 'Local variable: System.ArgumentException (2) 'Local variable: System.Exception (3)
Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.
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