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Type.FindMembers Method

Returns a filtered array of MemberInfo objects of the specified member type.

[Visual Basic]
Public Overridable Function FindMembers( _
   ByVal memberType As MemberTypes, _
   ByVal bindingAttr As BindingFlags, _
   ByVal filter As MemberFilter, _
   ByVal filterCriteria As Object _
) As MemberInfo()
[C#]
public virtual MemberInfo[] FindMembers(
 MemberTypes memberType,
 BindingFlags bindingAttr,
 MemberFilter filter,
 object filterCriteria
);
[C++]
public: virtual MemberInfo* FindMembers(
 MemberTypes memberType,
 BindingFlags bindingAttr,
 MemberFilter* filter,
 Object* filterCriteria
) [];
[JScript]
public function FindMembers(
   memberType : MemberTypes,
 bindingAttr : BindingFlags,
 filter : MemberFilter,
 filterCriteria : Object
) : MemberInfo[];

Parameters

memberType
A MemberTypes object indicating the type of member to search for.
bindingAttr
A bitmask comprised of one or more BindingFlags that specify how the search is conducted.

-or-

Zero, to return a null reference (Nothing in Visual Basic).

filter
The delegate that does the comparisons, returning true if the member currently being inspected matches the filterCriteria and false otherwise. You can use the FilterAttribute, FilterName, and FilterNameIgnoreCase delegates supplied by this class. The first uses the fields of FieldAttributes, MethodAttributes, and MethodImplAttributes as search criteria, and the other two delegates use String objects as the search criteria.
filterCriteria
The search criteria that determines whether a member is returned in the array of MemberInfo objects.

The fields of FieldAttributes, MethodAttributes, and MethodImplAttributes can be used in conjunction with the FilterAttribute delegate supplied by this class.

Return Value

A filtered array of MemberInfo objects of the specified member type.

-or-

An empty array of type MemberInfo, if the current Type does not have members of type memberType that match the filter criteria.

Exceptions

Exception Type Condition
ArgumentNullException filter is a null reference (Nothing in Visual Basic).

Remarks

This method can be overridden by a derived class.

Members include properties, methods, fields, events, and so on. If the requested type is non-public and the caller does not have ReflectionPermission to reflect non-public objects outside the current assembly, this method returns a null reference (Nothing in Visual Basic).

The following BindingFlags filter flags can be used to define which members to include in the search:

  • Instance to include instance members in the search.
  • Static to include static members in the search.
  • Public to include public members in the search.
  • NonPublic to include non-public members (that is, private and protected members) in the search.

The following BindingFlags modifier flags can be used to change how the search works:

  • DeclaredOnly to search only the members declared on the Type, not members that were simply inherited.

See System.Reflection.BindingFlags for more information.

Valid values for MemberType are defined in MemberInfo. If no such members are found, an empty array is returned.

Class initializers are available through GetMember, GetMembers, FindMembers, and GetConstructors.

Example

[Visual Basic, C#, C++] The following example finds all the members in a class that match the specified search criteria, and then displays the matched members.

[Visual Basic] 

Imports System
Imports System.Reflection
Imports Microsoft.VisualBasic

Class MyFindMembersClass

    Public Shared Sub Main()
        Dim objTest As New Object()
        Dim objType As Type = objTest.GetType()
        Dim arrayMemberInfo() As MemberInfo
        Try
            'Find all static or public methods in the Object 
            'class that match the specified name.
            arrayMemberInfo = objType.FindMembers(MemberTypes.Method, _
                              BindingFlags.Public Or BindingFlags.Static _
                              Or BindingFlags.Instance, _
                              New MemberFilter(AddressOf DelegateToSearchCriteria), _
                              "ReferenceEquals")

            Dim index As Integer
            For index = 0 To arrayMemberInfo.Length - 1
                Console.WriteLine("Result of FindMembers -" + ControlChars.Tab + _
                               arrayMemberInfo(index).ToString() + ControlChars.Cr)
            Next index
        Catch e As Exception
            Console.WriteLine("Exception : " + e.ToString())
        End Try
    End Sub 'Main

    Public Shared Function DelegateToSearchCriteria _
                            (ByVal objMemberInfo As MemberInfo, _
                             ByVal objSearch As Object) As Boolean
        ' Compare the name of the member function with the filter criteria.
        If objMemberInfo.Name.ToString() = objSearch.ToString() Then
            Return True
        Else
            Return False
        End If
    End Function 'DelegateToSearchCriteria 
End Class 'MyFindMembersClass

[C#] 
using System;
using System.Reflection;

class MyFindMembersClass
{
    public static void Main()
    {
        Object objTest = new Object();
        Type objType = objTest.GetType ();
        MemberInfo[] arrayMemberInfo;
        try
        {
            //Find all static or public methods in the Object class that match the specified name.
            arrayMemberInfo = objType.FindMembers(MemberTypes.Method,
                BindingFlags.Public | BindingFlags.Static| BindingFlags.Instance,
                new MemberFilter(DelegateToSearchCriteria),
                "ReferenceEquals");

            for(int index=0;index < arrayMemberInfo.Length ;index++)
                Console.WriteLine ("Result of FindMembers -\t"+ arrayMemberInfo[index].ToString() +"\n");                 
        }
        catch (Exception e)
        {
            Console.WriteLine ("Exception : " + e.ToString() );            
        }           
    }
    public static bool DelegateToSearchCriteria(MemberInfo objMemberInfo, Object objSearch)
    {
        // Compare the name of the member function with the filter criteria.
        if(objMemberInfo.Name.ToString() == objSearch.ToString())
            return true;
        else 
            return false;
    }
}

[C++] 
#using <mscorlib.dll>

using namespace System;
using namespace System::Reflection;

__gc class MyFindMembersClass {
public:
   static void Test() {
      Object* objTest = new Object();
      Type*  objType = objTest->GetType ();
      MemberInfo* arrayMemberInfo[];
      try {
         //Find all static or public methods in the Object class that match the specified name.
         arrayMemberInfo = objType->FindMembers(MemberTypes::Method,
            static_cast<BindingFlags>(BindingFlags::Public | BindingFlags::Static| BindingFlags::Instance),
            new MemberFilter(0, DelegateToSearchCriteria),
            S"ReferenceEquals");

         for (int index=0;index < arrayMemberInfo->Length ;index++)
            Console::WriteLine (S"Result of FindMembers -\t {0}",
            String::Concat( arrayMemberInfo[index], S"\n"));
      } catch (Exception* e) {
         Console::WriteLine (S"Exception : {0}", e);            
      }           
   }
   static bool DelegateToSearchCriteria(MemberInfo* objMemberInfo, Object* objSearch) {
      // Compare the name of the member function with the filter criteria.
      if (objMemberInfo->Name->Equals(objSearch->ToString()))
         return true;
      else 
         return false;
   }
};
int main()
{
   MyFindMembersClass::Test();
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

.NET Framework Security: 

See Also

Type Class | Type Members | System Namespace | MemberInfo | BindingFlags | DefaultBinder | ReflectionPermission | GetMember | GetMembers | GetDefaultMembers

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