ParameterInfo.IsDefined(Type, Boolean) Metoda

Definice

Obor názvů:

System.Reflection

Sestavení:

System.Runtime.dll

Zdroj:

ParameterInfo.cs

Určuje, zda se na tento parametr použije vlastní atribut zadaného typu nebo jeho odvozených typů.

public:
 virtual bool IsDefined(Type ^ attributeType, bool inherit);

public virtual bool IsDefined (Type attributeType, bool inherit);

abstract member IsDefined : Type * bool -> bool
override this.IsDefined : Type * bool -> bool

Public Overridable Function IsDefined (attributeType As Type, inherit As Boolean) As Boolean

Parametry

attributeType

Type

Objekt Type , který chcete vyhledat.

inherit

Boolean

Tento argument je ignorován pro objekty tohoto typu.

Návraty

Boolean

true pokud se na tento parametr použije jedna nebo více instancí attributeType nebo jejich odvozených typů, v opačném případě false.

Implementuje

IsDefined(Type, Boolean)

Výjimky

ArgumentNullException

attributeType je null.

ArgumentException

attributeType není Type objekt zadaný modulem CLR (Common Language Runtime).

Příklady

Následující příklad definuje dva vlastní atributy MyAttribute a MyDerivedAttribute. MyDerivedAttribute je odvozeno od MyAttribute. Příklad pak použije tyto atributy na parametry metody ukázkové třídy.

Při spuštění příkladu použije metodu IsDefined k otestování všech parametrů všech metod ve třídě example. Pak zobrazí parametry, které mají MyAttribute nebo MyDerivedAttribute.

// System::Reflection::ParameterInfo::GetCustomAttributes(Type, bool)
// System::Reflection::ParameterInfo::IsDefined(Type, bool)
using namespace System;
using namespace System::Reflection;

// Define a custom attribute with one named parameter.
[AttributeUsage(AttributeTargets::Parameter)]
public ref class MyAttribute: public Attribute
{
private:
   String^ myName;

public:
   MyAttribute( String^ name )
   {
      myName = name;
   }

   property String^ Name 
   {
      String^ get()
      {
         return myName;
      }
   }
};

// Derive another custom attribute from MyAttribute.
[AttributeUsage(AttributeTargets::Parameter)]
public ref class MyDerivedAttribute: public MyAttribute
{
public:
   MyDerivedAttribute( String^ name ) : MyAttribute( name ) {}
};

// Define a class with a method that has three parameters. Apply
// MyAttribute to one parameter, MyDerivedAttribute to another, and
// no attributes to the third. 
public ref class MyClass1
{
public:
   void MyMethod( [MyAttribute("This is an example parameter attribute")] 
                  int i,
                  [MyDerivedAttribute("This is another parameter attribute")] 
                  int j,
                  int k ){}
};

void main()
{
   // Get the type of the class 'MyClass1'.
   Type^ myType = MyClass1::typeid;

   // Get the members associated with the class 'MyClass1'.
   array<MethodInfo^>^myMethods = myType->GetMethods();

   // For each method of the class 'MyClass1', display all the parameters
   // to which MyAttribute or its derived types have been applied.
   for each ( MethodInfo^ mi in myMethods )
   {
      // Get the parameters for the method.
      array<ParameterInfo^>^ myParameters = mi->GetParameters();
      if ( myParameters->Length > 0 )
      {
         Console::WriteLine("\nThe following parameters of {0} have MyAttribute or a derived type:", mi);
         for each ( ParameterInfo^ pi in myParameters)
         {
            if (pi->IsDefined(MyAttribute::typeid, false))
            {
               Console::WriteLine("Parameter {0}, name = {1}, type = {2}", 
                  pi->Position, pi->Name, pi->ParameterType);
            }
         }
      }
   }
}

/* This code example produces the following output:

The following parameters of Void MyMethod(Int32, Int32, Int32) have MyAttribute or a derived type:
Parameter 0, name = i, type = System.Int32
Parameter 1, name = j, type = System.Int32

The following parameters of Boolean Equals(System.Object) have MyAttribute or a derived type:
 */

using System;
using System.Reflection;

// Define a custom attribute with one named parameter.
[AttributeUsage(AttributeTargets.Parameter)]
public class MyAttribute : Attribute
{
    private string myName;
    public MyAttribute(string name)
    {
        myName = name;
    }
    public string Name
    {
        get
        {
            return myName;
        }
    }
}

// Derive another custom attribute from MyAttribute
[AttributeUsage(AttributeTargets.Parameter)]
public class MyDerivedAttribute : MyAttribute
{
    public MyDerivedAttribute(string name) : base(name) {}
}

// Define a class with a method that has three parameters. Apply
// MyAttribute to one parameter, MyDerivedAttribute to another, and
// no attributes to the third.
public class MyClass1
{
    public void MyMethod(
        [MyAttribute("This is an example parameter attribute")]
        int i,
        [MyDerivedAttribute("This is another parameter attribute")]
        int j,
        int k )
    {
        return;
    }
}

public class MemberInfo_GetCustomAttributes
{
    public static void Main()
    {
        // Get the type of the class 'MyClass1'.
        Type myType = typeof(MyClass1);
        // Get the members associated with the class 'MyClass1'.
        MethodInfo[] myMethods = myType.GetMethods();

        // For each method of the class 'MyClass1', display all the parameters
        // to which MyAttribute or its derived types have been applied.
        foreach (MethodInfo mi in myMethods)
        {
            // Get the parameters for the method.
            ParameterInfo[] myParameters = mi.GetParameters();
            if (myParameters.Length > 0)
            {
                Console.WriteLine("\nThe following parameters of {0} have MyAttribute or a derived type: ", mi);
                foreach (ParameterInfo pi in myParameters)
                {
                    if (pi.IsDefined(typeof(MyAttribute), false))
                    {
                        Console.WriteLine("Parameter {0}, name = {1}, type = {2}",
                            pi.Position, pi.Name, pi.ParameterType);
                    }
                }
            }
        }
    }
}

/* This code example produces the following output:

The following parameters of Void MyMethod(Int32, Int32, Int32) have MyAttribute or a derived type:
Parameter 0, name = i, type = System.Int32
Parameter 1, name = j, type = System.Int32

The following parameters of Boolean Equals(System.Object) have MyAttribute or a derived type:
 */

Imports System.Reflection

' Define a custom attribute with one named parameter.
<AttributeUsage(AttributeTargets.Parameter)> _
Public Class MyAttribute
    Inherits Attribute
    Private myName As String

    Public Sub New(ByVal name As String)
        myName = name
    End Sub 

    Public ReadOnly Property Name() As String
        Get
            Return myName
        End Get
    End Property
End Class 

' Derive another custom attribute from MyAttribute
<AttributeUsage(AttributeTargets.Parameter)> _
Public Class MyDerivedAttribute
    Inherits MyAttribute

    Public Sub New(ByVal name As String)
        MyBase.New(name)
    End Sub 
End Class

' Define a class with a method that has three parameters. Apply
' MyAttribute to one parameter, MyDerivedAttribute to another, and
' no attributes to the third. 
Public Class MyClass1

    Public Sub MyMethod(<MyAttribute("This is an example parameter attribute")> _
                        ByVal i As Integer, _
                        <MyDerivedAttribute("This is another parameter attribute")> _
                        ByVal j As Integer, _
                        ByVal k As Integer)
        Return
    End Sub 
End Class 

Public Class MemberInfo_GetCustomAttributes

    Public Shared Sub Main()
        ' Get the type of the class 'MyClass1'.
        Dim myType As Type = GetType(MyClass1)
        ' Get the members associated with the class 'MyClass1'.
        Dim myMethods As MethodInfo() = myType.GetMethods()

        ' For each method of the class 'MyClass1', display all the parameters
        ' to which MyAttribute or its derived types have been applied.
        For Each mi As MethodInfo In myMethods
            ' Get the parameters for the method.
            Dim myParameters As ParameterInfo() = mi.GetParameters()
            If myParameters.Length > 0 Then
                Console.WriteLine(vbCrLf & "The following parameters of {0} have MyAttribute or a derived type: ", mi)
                For Each pi As ParameterInfo In myParameters
                    If pi.IsDefined(GetType(MyAttribute), False) Then
                        Console.WriteLine("Parameter {0}, name = {1}, type = {2}", _
                            pi.Position, pi.Name, pi.ParameterType)
                    End If
                Next
            End If
        Next
    End Sub 
End Class 

' This code example produces the following output:
'
'The following parameters of Void MyMethod(Int32, Int32, Int32) have MyAttribute or a derived type:
'Parameter 0, name = i, type = System.Int32
'Parameter 1, name = j, type = System.Int32
'
'The following parameters of Boolean Equals(System.Object) have MyAttribute or a derived type:

Poznámky

Tato metoda ignoruje inherit parametr. Pokud chcete vyhledat atributy parametrů v řetězu dědičnosti Attribute.IsDefined , použijte příslušná přetížení metody.