Ver información de tipos
La clase System.Type es fundamental para la reflexión. Common Language Runtime crea Type para un tipo cargado cuando lo solicita la reflexión. Se pueden utilizar los métodos, campos, propiedades y clases anidadas de un objeto Type para averiguarlo todo sobre dicho tipo.
Se utiliza Assembly.GetType o Assembly.GetTypes para obtener objetos Type de ensamblados no cargados, pasando el nombre del tipo o tipos que se desee. Utilice Type.GetType para obtener los objetos Type de un ensamblado cargado. Utilice Module.GetType y Module.GetTypes para obtener los objetos Type del módulo.
Nota
Si desea examinar y manipular tipos y métodos genéricos, vea la información adicional proporcionada en Reflexión y tipos genéricos y en Cómo: Examinar y crear instancias de tipos genéricos mediante la reflexión.
En el ejemplo siguiente se muestra la sintaxis necesaria para obtener el objeto Assembly y el módulo de un ensamblado.
' Gets the mscorlib assembly in which the object is defined.
Dim a As Reflection.Assembly = GetType(Object).Module.Assembly
// Gets the mscorlib assembly in which the object is defined.
Assembly a = typeof(Object).Module.Assembly;
En el ejemplo siguiente se muestra cómo obtener los objetos Type de un ensamblado cargado.
' Loads an assembly using its file name.
Dim a As Reflection.Assembly = Reflection.Assembly.LoadFrom("MyExe.exe")
' Gets the type names from the assembly.
Dim types2 As Type() = a.GetTypes()
Dim t As Type
For Each t In types2
Console.WriteLine(t.FullName)
Next t
// Loads an assembly using its file name.
Assembly a = Assembly.LoadFrom ("MyExe.exe");
// Gets the type names from the assembly.
Type [] types2 = a.GetTypes ();
foreach (Type t in types2)
{
Console.WriteLine (t.FullName);
}
Tras obtener un Type, existen varias maneras de obtener información sobre los miembros de dicho tipo. Por ejemplo, para obtener información sobre todos los miembros del tipo, hay que llamar al método Type.GetMembers, que obtiene una matriz de objetos MemberInfo que describen cada uno de los miembros del actual tipo.
También se pueden utilizar métodos en la clase Type para recuperar información sobre uno o varios constructores, métodos, eventos, propiedades o campos especificados por su nombre. Por ejemplo, Type.GetConstructor encapsula un constructor específico de la clase actual.
Si tiene Type, puede utilizar la propiedad Type.Module para obtener un objeto que encapsule el módulo que contiene dicho tipo. Se utiliza la propiedad Module.Assembly para buscar un objeto que encapsule el ensamblado que contiene el módulo. Para obtener directamente el ensamblado que encapsule el tipo, se puede utilizar la propiedad Type.Assembly.
System.Type y ConstructorInfo
En el ejemplo siguiente se indica cómo enumerar los constructores de una clase; en este caso, la clase String.
' This program lists all the public constructors
' of the System.String class.
Imports System
Imports System.Reflection
Class ListMembers
Public Shared Sub Main()
Dim t As Type = GetType(String)
Console.WriteLine("Listing all the public constructors of the {0} type", t)
' Constructors.
Dim ci As ConstructorInfo() = t.GetConstructors((BindingFlags.Public Or BindingFlags.Instance))
Console.WriteLine("//Constructors")
PrintMembers(ci)
End Sub
Public Shared Sub PrintMembers(ms() As MemberInfo)
Dim m As MemberInfo
For Each m In ms
Console.WriteLine("{0}{1}", " ", m)
Next m
Console.WriteLine()
End Sub
End Class
// This program lists all the public constructors
// of the System.String class.
using System;
using System.Reflection;
class ListMembers {
public static void Main(String[] args) {
Type t = typeof(System.String);
Console.WriteLine ("Listing all the public constructors of the {0} type", t);
// Constructors.
ConstructorInfo[] ci = t.GetConstructors(BindingFlags.Public | BindingFlags.Instance);
Console.WriteLine ("//Constructors");
PrintMembers (ci);
}
public static void PrintMembers(MemberInfo [] ms) {
foreach (MemberInfo m in ms) {
Console.WriteLine ("{0}{1}", " ", m);
}
Console.WriteLine();
}
}
MemberInfo, MethodInfo, FieldInfo y PropertyInfo
Para obtener información sobre los métodos, propiedades, eventos y campos del tipo, hay que utilizar los objetos MemberInfo, MethodInfo, FieldInfo o PropertyInfo.
En el ejemplo siguiente, se utiliza MemberInfo para mostrar el número de miembros de la clase System.IO.File y se utiliza la propiedad System.Type.IsPublic para determinar la visibilidad de la clase.
Option Explicit
Option Strict
Imports System
Imports System.IO
Imports System.Reflection
Imports Microsoft.VisualBasic
Class Mymemberinfo
Public Shared Sub Main()
Console.WriteLine(ControlChars.Cr & "Reflection.MemberInfo")
' Gets the Type and MemberInfo.
Dim MyType As Type = Type.GetType("System.IO.File")
Dim Mymemberinfoarray As MemberInfo() = MyType.GetMembers()
' Gets and displays the DeclaringType method.
Console.WriteLine(ControlChars.Cr & "There are {0} members in {1}.", Mymemberinfoarray.Length, MyType.FullName)
Console.WriteLine("{0}.", MyType.FullName)
If MyType.IsPublic Then
Console.WriteLine("{0} is public.", MyType.FullName)
End If
End Sub
End Class
using System;
using System.IO;
using System.Reflection;
class Mymemberinfo
{
public static void Main(string[] args)
{
Console.WriteLine ("\nReflection.MemberInfo");
// Gets the Type and MemberInfo.
Type MyType =Type.GetType("System.IO.File");
MemberInfo[] Mymemberinfoarray = MyType.GetMembers();
// Gets and displays the DeclaringType method.
Console.WriteLine("\nThere are {0} members in {1}.",
Mymemberinfoarray.Length, MyType.FullName);
Console.WriteLine("{0}.", MyType.FullName);
if (MyType.IsPublic)
{
Console.WriteLine("{0} is public.", MyType.FullName);
}
}
}
En el ejemplo siguiente se investiga el tipo del miembro especificado. Realiza una reflexión en un miembro de la clase MemberInfo y muestra su tipo.
' This code displays information about the GetValue method of FieldInfo.
Option Explicit
Option Strict
Imports System
Imports System.Reflection
Class MyMethodInfo
Public Shared Sub Main()
Console.WriteLine("Reflection.MethodInfo")
' Gets and displays the Type.
Dim MyType As Type = Type.GetType("System.Reflection.FieldInfo")
' Specifies the member for which you want type information.
Dim Mymethodinfo As MethodInfo = MyType.GetMethod("GetValue")
Console.WriteLine((MyType.FullName & "." & Mymethodinfo.Name))
' Gets and displays the MemberType property.
Dim Mymembertypes As MemberTypes = Mymethodinfo.MemberType
If MemberTypes.Constructor = Mymembertypes Then
Console.WriteLine("MemberType is of type All")
ElseIf MemberTypes.Custom = Mymembertypes Then
Console.WriteLine("MemberType is of type Custom")
ElseIf MemberTypes.Event = Mymembertypes Then
Console.WriteLine("MemberType is of type Event")
ElseIf MemberTypes.Field = Mymembertypes Then
Console.WriteLine("MemberType is of type Field")
ElseIf MemberTypes.Method = Mymembertypes Then
Console.WriteLine("MemberType is of type Method")
ElseIf MemberTypes.Property = Mymembertypes Then
Console.WriteLine("MemberType is of type Property")
ElseIf MemberTypes.TypeInfo = Mymembertypes Then
Console.WriteLine("MemberType is of type TypeInfo")
End If
Return
End Sub
End Class
// This code displays information about the GetValue method of FieldInfo.
using System;
using System.Reflection;
class MyMethodInfo {
public static int Main() {
Console.WriteLine("Reflection.MethodInfo");
// Gets and displays the Type.
Type MyType = Type.GetType("System.Reflection.FieldInfo");
// Specifies the member for which you want type information.
MethodInfo Mymethodinfo = MyType.GetMethod("GetValue");
Console.WriteLine(MyType.FullName + "." + Mymethodinfo.Name);
// Gets and displays the MemberType property.
MemberTypes Mymembertypes = Mymethodinfo.MemberType;
if (MemberTypes.Constructor == Mymembertypes) {
Console.WriteLine("MemberType is of type All");
}
else if (MemberTypes.Custom == Mymembertypes) {
Console.WriteLine("MemberType is of type Custom");
}
else if (MemberTypes.Event == Mymembertypes) {
Console.WriteLine("MemberType is of type Event");
}
else if (MemberTypes.Field == Mymembertypes) {
Console.WriteLine("MemberType is of type Field");
}
else if (MemberTypes.Method == Mymembertypes) {
Console.WriteLine("MemberType is of type Method");
}
else if (MemberTypes.Property == Mymembertypes) {
Console.WriteLine("MemberType is of type Property");
}
else if (MemberTypes.TypeInfo == Mymembertypes) {
Console.WriteLine("MemberType is of type TypeInfo");
}
return 0;
}
}
En el ejemplo siguiente se utilizan todas las clases *Info de reflexión junto con BindingFlags para enumerar todos los miembros (constructores, campos, propiedades, eventos y métodos) de la clase especificada, dividiendo los miembros en las categorías de miembros estáticos y miembros de instancia.
' This program lists all the members of the
' System.IO.BufferedStream class.
Imports System
Imports System.IO
Imports System.Reflection
Imports Microsoft.VisualBasic
Class ListMembers
Public Shared Sub Main()
' Specifies the class.
Dim t As Type = GetType(System.IO.BufferedStream)
Console.WriteLine("Listing all the members (public and non public) of the {0} type", t)
' Lists static fields first.
Dim fi As FieldInfo() = t.GetFields((BindingFlags.Static Or BindingFlags.NonPublic Or BindingFlags.Public))
Console.WriteLine("// Static Fields")
PrintMembers(fi)
' Static properties.
Dim pi As PropertyInfo() = t.GetProperties((BindingFlags.Static Or BindingFlags.NonPublic Or BindingFlags.Public))
Console.WriteLine("// Static Properties")
PrintMembers(pi)
' Static events.
Dim ei As EventInfo() = t.GetEvents((BindingFlags.Static Or BindingFlags.NonPublic Or BindingFlags.Public))
Console.WriteLine("// Static Events")
PrintMembers(ei)
' Static methods.
Dim mi As MethodInfo() = t.GetMethods((BindingFlags.Static Or BindingFlags.NonPublic Or BindingFlags.Public))
Console.WriteLine("// Static Methods")
PrintMembers(mi)
' Constructors.
Dim ci As ConstructorInfo() = t.GetConstructors((BindingFlags.Instance Or BindingFlags.NonPublic Or BindingFlags.Public))
Console.WriteLine("// Constructors")
PrintMembers(ci)
' Instance fields.
fi = t.GetFields((BindingFlags.Instance Or BindingFlags.NonPublic Or BindingFlags.Public))
Console.WriteLine("// Instance Fields")
PrintMembers(fi)
' Instance properites.
pi = t.GetProperties((BindingFlags.Instance Or BindingFlags.NonPublic Or BindingFlags.Public))
Console.WriteLine("// Instance Properties")
PrintMembers(pi)
' Instance events.
ei = t.GetEvents((BindingFlags.Instance Or BindingFlags.NonPublic Or BindingFlags.Public))
Console.WriteLine("// Instance Events")
PrintMembers(ei)
' Instance methods.
mi = t.GetMethods((BindingFlags.Instance Or BindingFlags.NonPublic Or BindingFlags.Public))
Console.WriteLine("// Instance Methods")
PrintMembers(mi)
Console.WriteLine(ControlChars.CrLf & "Press ENTER to exit.")
Console.Read()
End Sub
Public Shared Sub PrintMembers(ms() As MemberInfo)
Dim m As MemberInfo
For Each m In ms
Console.WriteLine("{0}{1}", " ", m)
Next m
Console.WriteLine()
End Sub
End Class
// This program lists all the members of the
// System.IO.BufferedStream class.
using System;
using System.IO;
using System.Reflection;
class ListMembers {
public static void Main(String[] args) {
// Specifies the class.
Type t = typeof (System.IO.BufferedStream);
Console.WriteLine ("Listing all the members (public and non public) of the {0} type", t);
// Lists static fields first.
FieldInfo [] fi = t.GetFields (BindingFlags.Static |
BindingFlags.NonPublic | BindingFlags.Public);
Console.WriteLine ("// Static Fields");
PrintMembers (fi);
// Static properties.
PropertyInfo [] pi = t.GetProperties (BindingFlags.Static |
BindingFlags.NonPublic | BindingFlags.Public);
Console.WriteLine ("// Static Properties");
PrintMembers (pi);
// Static events.
EventInfo [] ei = t.GetEvents (BindingFlags.Static |
BindingFlags.NonPublic | BindingFlags.Public);
Console.WriteLine ("// Static Events");
PrintMembers (ei);
// Static methods.
MethodInfo [] mi = t.GetMethods (BindingFlags.Static |
BindingFlags.NonPublic | BindingFlags.Public);
Console.WriteLine ("// Static Methods");
PrintMembers (mi);
// Constructors.
ConstructorInfo [] ci = t.GetConstructors (BindingFlags.Instance |
BindingFlags.NonPublic | BindingFlags.Public);
Console.WriteLine ("// Constructors");
PrintMembers (ci);
// Instance fields.
fi = t.GetFields (BindingFlags.Instance | BindingFlags.NonPublic |
BindingFlags.Public);
Console.WriteLine ("// Instance Fields");
PrintMembers (fi);
// Instance properites.
pi = t.GetProperties (BindingFlags.Instance | BindingFlags.NonPublic |
BindingFlags.Public);
Console.WriteLine ("// Instance Properties");
PrintMembers (pi);
// Instance events.
ei = t.GetEvents (BindingFlags.Instance | BindingFlags.NonPublic |
BindingFlags.Public);
Console.WriteLine ("// Instance Events");
PrintMembers (ei);
// Instance methods.
mi = t.GetMethods (BindingFlags.Instance | BindingFlags.NonPublic
| BindingFlags.Public);
Console.WriteLine ("// Instance Methods");
PrintMembers (mi);
Console.WriteLine ("\r\nPress ENTER to exit.");
Console.Read();
}
public static void PrintMembers (MemberInfo [] ms) {
foreach (MemberInfo m in ms) {
Console.WriteLine ("{0}{1}", " ", m);
}
Console.WriteLine();
}
}
Vea también
Referencia
Ver información de tipos
BindingFlags
Assembly.GetType
Assembly.GetTypes
Type.GetType
Type.GetMembers
Type.GetFields
Module.GetType
Module.GetTypes
MemberInfo
ConstructorInfo
MethodInfo
FieldInfo
EventInfo
ParameterInfo