GetMethod Method (String, Type[])

Type.GetMethod Method (String, Type())

 

Searches for the specified public method whose parameters match the specified argument types.

Namespace:   System
Assembly:  mscorlib (in mscorlib.dll)

Public Function GetMethod (
	name As String,
	types As Type()
) As MethodInfo

Parameters

name
Type: System.String

The string containing the name of the public method to get.

types
Type: System.Type()

An array of Type objects representing the number, order, and type of the parameters for the method to get.

-or-

An empty array of Type objects (as provided by the EmptyTypes field) to get a method that takes no parameters.

Return Value

Type: System.Reflection.MethodInfo

An object representing the public method whose parameters match the specified argument types, if found; otherwise, null.

Exception Condition
AmbiguousMatchException

More than one method is found with the specified name and specified parameters.

ArgumentNullException

name is null.

-or-

types is null.

-or-

One of the elements in types is null.

ArgumentException

types is multidimensional.

The search for name is case-sensitive. The search includes public static and public instance methods.

System_CAPS_noteNote

You cannot omit parameters when looking up constructors and methods. You can only omit parameters when invoking.

If the current Type represents a constructed generic type, this method returns the MethodInfo with the type parameters replaced by the appropriate type arguments.

If the current Type represents a type parameter in the definition of a generic type or generic method, this method searches the methods of the class constraint, or the methods of Object if there is no class constraint.

System_CAPS_noteNote

The name parameter cannot include type arguments. For example, the C# code GetMethod("MyGenericMethod<int>") searches for a method with the text name "MyGenericMethod<int>", rather than for a method named MyGenericMethod that has one generic argument of type int. Instead, use GetMethod("MyGenericMethod") with the appropriate parameter in the types array.

The following example finds specific overloads of MethodA, specifying a variety of argument types.

System_CAPS_noteNote

The Visual C# 2005 example requires the /unsafe compiler option.


Imports System
Imports System.Reflection
Imports System.Runtime.InteropServices

Class Program

    ' Methods to get:

    Public Overloads Sub MethodA(ByVal i As Integer, ByVal l As Long)

    End Sub

    Public Overloads Sub MethodA(ByVal i() As Integer)

    End Sub

    Public Overloads Sub MethodA(ByRef r As Integer)

    End Sub

    ' Method that takes an out parameter. Note that an Imports
    ' reference is needed to System.Runtime.InteropServices 
    ' for the <OutAttribute>, which can be shortened to <Out>.
    Public Overloads Sub MethodA(ByVal i As Integer, <Out()> ByRef o As Integer)
        o = 100
    End Sub

    Public Shared Sub Main(ByVal args() As String)
        Dim mInfo As MethodInfo

        ' Get MethodA(i As Integer i, l As Long)
        mInfo = GetType(Program).GetMethod("MethodA", New Type() {GetType(Integer), GetType(Long)})
        Console.WriteLine("Found method: {0}", mInfo)

        ' Get  MethodA(i As Integer())
        mInfo = GetType(Program).GetMethod("MethodA", New Type() {GetType(Integer())})
        Console.WriteLine("Found method: {0}", mInfo)

        ' Get MethodA(ByRef r As Integer)
        mInfo = GetType(Program).GetMethod("MethodA", New Type() {GetType(Integer).MakeByRefType})
        Console.WriteLine("Found method: {0}", mInfo)

        ' Get MethodA(i As Integer, ByRef r As Integer)
        mInfo = GetType(Program).GetMethod("MethodA", New Type() {GetType(Integer), _
            GetType(Integer).MakeByRefType})
        Console.WriteLine("Found method: {0}", mInfo)

    End Sub
End Class

The following example retrieves MethodInfo objects that represent the Add methods of a non-generic type (the ArrayList class), an open generic type (the List(Of T) class), and a closed generic type (the List(Of String) type.

Imports System.Collections
Imports System.Collections.Generic
Imports System.Reflection

Module Example
   Public Sub Main()
      ' Get a Type object that represents a non-generic type.
      GetAddMethod(GetType(ArrayList))

      Dim list As New List(Of String)()
      ' Get a Type object that represents a constructed generic type.
      Dim closed As Type = list.GetType()
      GetAddMethod(closed)

      ' Get a Type object that represents an open generic type.
      Dim open As Type = GetType(List(Of))
      GetAddMethod(open)
   End Sub

   Private Sub GetAddMethod(typ As Type)
      Dim method As MethodInfo
      ' Determine if this is a generic type.
      If typ.IsGenericType Then
         ' Is it an open generic type?
         If typ.ContainsGenericParameters Then
            method = typ.GetMethod("Add", typ.GetGenericArguments())
         ' Get closed generic type arguments.
         Else
            method = typ.GetMethod("Add", typ.GenericTypeArguments)
         End If
      ' This is not a generic type.
      Else
         method = typ.GetMethod("Add", { GetType(Object) } )
      End If
      ' Test if an Add method was found.
      If method Is Nothing Then 
         Console.WriteLine("No Add method found.")
         Exit Sub
      End If   

      Dim t As Type = method.ReflectedType
      Console.Write("{0}.{1}.{2}(", t.Namespace, t.Name, method.Name)
      Dim params() As ParameterInfo = method.GetParameters()
      For ctr As Integer = 0 To params.Length - 1
         Console.Write("{0}{1}", params(ctr).ParameterType.Name, 
                       If(ctr < params.Length - 1, ", ", ""))
      Next
      Console.WriteLine(")")
   End Sub
End Module
' The example displays the following output:
'       System.Collections.ArrayList.Add(Object)
'       System.Collections.Generic.List`1.Add(String)
'       System.Collections.Generic.List`1.Add(T)

The example defines a GetAddMethod method that retrieves the appropriate MethodInfo object. To provide the types argument for an open generic type, it calls the Type.GetGenericArguments method. To provide the types argument for a closed generic type, it retrieves the value of the Type.GenericTypeArguments property.

.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Return to top
Show:
© 2016 Microsoft