ParameterBuilder Classe

Definizione

Spazio dei nomi:

System.Reflection.Emit

Assembly:

System.Reflection.Emit.ILGeneration.dll

Source:

ParameterBuilder.cs

Crea o associa informazioni sui parametri.

public ref class ParameterBuilder abstract

public abstract class ParameterBuilder

type ParameterBuilder = class

Public MustInherit Class ParameterBuilder

Ereditarietà

Object

ParameterBuilder

Esempio

Nell'esempio seguente viene illustrato come creare un metodo dinamico con un parametro passato per riferimento usando ParameterBuilder.

using namespace System;
using namespace System::Threading;
using namespace System::Reflection;
using namespace System::Reflection::Emit;
Type^ BuildCustomerDataType()
{
   AppDomain^ myDomain = Thread::GetDomain();
   AssemblyName^ myAsmName = gcnew AssemblyName;
   myAsmName->Name = "MyDynamicAssembly";
   AssemblyBuilder^ myAsmBuilder = myDomain->DefineDynamicAssembly( myAsmName, AssemblyBuilderAccess::Run );
   ModuleBuilder^ myModBuilder = myAsmBuilder->DefineDynamicModule( "MyMod" );
   TypeBuilder^ myTypeBuilder = myModBuilder->DefineType( "CustomerData", TypeAttributes::Public );
   FieldBuilder^ customerNameBldr = myTypeBuilder->DefineField( "customerName", String::typeid, FieldAttributes::Private );
   FieldBuilder^ acctIDBldr = myTypeBuilder->DefineField( "acctID", String::typeid, FieldAttributes::Private );
   FieldBuilder^ balanceAmtBldr = myTypeBuilder->DefineField( "balanceAmt", double::typeid, FieldAttributes::Private );
   array<Type^>^temp0 = {String::typeid,String::typeid,double::typeid};
   ConstructorBuilder^ myCtorBuilder = myTypeBuilder->DefineConstructor( MethodAttributes::Public, CallingConventions::HasThis, temp0 );
   ILGenerator^ ctorIL = myCtorBuilder->GetILGenerator();
   Type^ objType = Type::GetType( "System.Object" );
   ConstructorInfo^ objCtor = objType->GetConstructor( gcnew array<Type^>(0) );
   ctorIL->Emit( OpCodes::Ldarg_0 );
   ctorIL->Emit( OpCodes::Call, objCtor );
   ctorIL->Emit( OpCodes::Ldarg_0 );
   ctorIL->Emit( OpCodes::Ldarg_1 );
   ctorIL->Emit( OpCodes::Stfld, customerNameBldr );
   ctorIL->Emit( OpCodes::Ldarg_0 );
   ctorIL->Emit( OpCodes::Ldarg_2 );
   ctorIL->Emit( OpCodes::Stfld, acctIDBldr );
   ctorIL->Emit( OpCodes::Ldarg_0 );
   ctorIL->Emit( OpCodes::Ldarg_3 );
   ctorIL->Emit( OpCodes::Stfld, balanceAmtBldr );
   ctorIL->Emit( OpCodes::Ret );
   
   // This method will take an amount from a static pool and add it to the balance.
   // Note that we are passing the first parameter, fundsPool, by reference. Therefore,
   // we need to inform the MethodBuilder to expect a ref, by declaring the first
   // parameter's type to be System::Double& (a reference to a double).
   array<Type^>^temp4 = {Type::GetType( "System.Double&" ),double::typeid};
   MethodBuilder^ myMthdBuilder = myTypeBuilder->DefineMethod( "AddFundsFromPool", MethodAttributes::Public, double::typeid, temp4 );
   ParameterBuilder^ poolRefBuilder = myMthdBuilder->DefineParameter( 1, ParameterAttributes::Out, "fundsPool" );
   ParameterBuilder^ amountFromPoolBuilder = myMthdBuilder->DefineParameter( 2, ParameterAttributes::In, "amountFromPool" );
   ILGenerator^ mthdIL = myMthdBuilder->GetILGenerator();
   mthdIL->Emit( OpCodes::Ldarg_1 );
   mthdIL->Emit( OpCodes::Ldarg_1 );
   mthdIL->Emit( OpCodes::Ldind_R8 );
   mthdIL->Emit( OpCodes::Ldarg_2 );
   mthdIL->Emit( OpCodes::Sub );
   mthdIL->Emit( OpCodes::Stind_R8 );
   mthdIL->Emit( OpCodes::Ldarg_0 );
   mthdIL->Emit( OpCodes::Ldarg_0 );
   mthdIL->Emit( OpCodes::Ldfld, balanceAmtBldr );
   mthdIL->Emit( OpCodes::Ldarg_2 );
   mthdIL->Emit( OpCodes::Add );
   mthdIL->Emit( OpCodes::Stfld, balanceAmtBldr );
   mthdIL->Emit( OpCodes::Ldarg_0 );
   mthdIL->Emit( OpCodes::Ldfld, balanceAmtBldr );
   mthdIL->Emit( OpCodes::Ret );
   return myTypeBuilder->CreateType();
}

int main()
{
   Type^ custType = nullptr;
   Object^ custObj = nullptr;
   array<Type^>^custArgTypes = {String::typeid,String::typeid,double::typeid};
   
   // Call the method to build our dynamic class.
   custType = BuildCustomerDataType();
   Console::WriteLine( "---" );
   ConstructorInfo^ myCustCtor = custType->GetConstructor( custArgTypes );
   double initialBalance = 100.00;
   array<Object^>^temp5 = {"Joe Consumer","5678-XYZ",initialBalance};
   custObj = myCustCtor->Invoke( temp5 );
   array<MemberInfo^>^myMemberInfo = custType->GetMember( "AddFundsFromPool" );
   double thePool = 1000.00;
   Console::WriteLine( "The pool is currently ${0}", thePool );
   Console::WriteLine( "The original balance of the account instance is ${0}", initialBalance );
   double amountFromPool = 50.00;
   Console::WriteLine( "The amount to be subtracted from the pool and added to the account is ${0}", amountFromPool );
   Console::WriteLine( "---" );
   Console::WriteLine( "Calling {0} ...", myMemberInfo[ 0 ] );
   Console::WriteLine( "---" );
   array<Object^>^passMe = {thePool,amountFromPool};
   Console::WriteLine( "The new balance in the account instance is ${0}", custType->InvokeMember( "AddFundsFromPool", BindingFlags::InvokeMethod, nullptr, custObj, passMe ) );
   thePool = safe_cast<double>(passMe[ 0 ]);
   Console::WriteLine( "The new amount in the pool is ${0}", thePool );
}

using System;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;

class ParamBuilderDemo

{

   public static Type BuildCustomerDataType()
   {

    AppDomain myDomain = Thread.GetDomain();
    AssemblyName myAsmName = new AssemblyName();
    myAsmName.Name = "MyDynamicAssembly";

    AssemblyBuilder myAsmBuilder = myDomain.DefineDynamicAssembly(myAsmName,
                        AssemblyBuilderAccess.Run);

    ModuleBuilder myModBuilder = myAsmBuilder.DefineDynamicModule("MyMod");

    TypeBuilder myTypeBuilder = myModBuilder.DefineType("CustomerData",
                        TypeAttributes.Public);

    FieldBuilder customerNameBldr = myTypeBuilder.DefineField("customerName",
                            typeof(string),
                            FieldAttributes.Private);
    FieldBuilder acctIDBldr = myTypeBuilder.DefineField("acctID",
                            typeof(string),
                            FieldAttributes.Private);
    FieldBuilder balanceAmtBldr = myTypeBuilder.DefineField("balanceAmt",
                            typeof(double),
                            FieldAttributes.Private);
                                
    ConstructorBuilder myCtorBuilder = myTypeBuilder.DefineConstructor(
                            MethodAttributes.Public,
                            CallingConventions.HasThis,
                            new Type[] { typeof(string),
                                     typeof(string),
                                     typeof(double) });

    ILGenerator ctorIL = myCtorBuilder.GetILGenerator();

    Type objType = Type.GetType("System.Object");
        ConstructorInfo objCtor = objType.GetConstructor(new Type[] {});

    ctorIL.Emit(OpCodes.Ldarg_0);
    ctorIL.Emit(OpCodes.Call, objCtor);

    ctorIL.Emit(OpCodes.Ldarg_0);
    ctorIL.Emit(OpCodes.Ldarg_1);
    ctorIL.Emit(OpCodes.Stfld, customerNameBldr);

    ctorIL.Emit(OpCodes.Ldarg_0);
    ctorIL.Emit(OpCodes.Ldarg_2);
    ctorIL.Emit(OpCodes.Stfld, acctIDBldr);

    ctorIL.Emit(OpCodes.Ldarg_0);
    ctorIL.Emit(OpCodes.Ldarg_3);
    ctorIL.Emit(OpCodes.Stfld, balanceAmtBldr);

    ctorIL.Emit(OpCodes.Ret);

    // This method will take an amount from a static pool and add it to the balance.

    // Note that we are passing the first parameter, fundsPool, by reference. Therefore,
    // we need to inform the MethodBuilder to expect a ref, by declaring the first
    // parameter's type to be System.Double& (a reference to a double).

    MethodBuilder myMthdBuilder = myTypeBuilder.DefineMethod("AddFundsFromPool",
                        MethodAttributes.Public,
                        typeof(double),
                        new Type[] { Type.GetType("System.Double&"),
                                 typeof(double) });

    ParameterBuilder poolRefBuilder = myMthdBuilder.DefineParameter(1,
                        ParameterAttributes.Out,
                        "fundsPool");

    ParameterBuilder amountFromPoolBuilder = myMthdBuilder.DefineParameter(2,
                        ParameterAttributes.In,
                            "amountFromPool");

    ILGenerator mthdIL = myMthdBuilder.GetILGenerator();

    mthdIL.Emit(OpCodes.Ldarg_1);
    mthdIL.Emit(OpCodes.Ldarg_1);
    mthdIL.Emit(OpCodes.Ldind_R8);
    mthdIL.Emit(OpCodes.Ldarg_2);
    mthdIL.Emit(OpCodes.Sub);

    mthdIL.Emit(OpCodes.Stind_R8);

    mthdIL.Emit(OpCodes.Ldarg_0);
    mthdIL.Emit(OpCodes.Ldarg_0);
    mthdIL.Emit(OpCodes.Ldfld, balanceAmtBldr);
    mthdIL.Emit(OpCodes.Ldarg_2);
    mthdIL.Emit(OpCodes.Add);

    mthdIL.Emit(OpCodes.Stfld, balanceAmtBldr);

    mthdIL.Emit(OpCodes.Ldarg_0);
    mthdIL.Emit(OpCodes.Ldfld, balanceAmtBldr);
    mthdIL.Emit(OpCodes.Ret);

    return myTypeBuilder.CreateType();
   }

   public static void Main()
   {
    Type custType = null;
    object custObj = null;

    Type[] custArgTypes = new Type[] {typeof(string), typeof(string), typeof(double)};
    
    // Call the method to build our dynamic class.

    custType = BuildCustomerDataType();

    Console.WriteLine("---");

    ConstructorInfo myCustCtor = custType.GetConstructor(custArgTypes);
    double initialBalance = 100.00;
    custObj = myCustCtor.Invoke(new object[] { "Joe Consumer",
                           "5678-XYZ",
                           initialBalance });

    MemberInfo[] myMemberInfo = custType.GetMember("AddFundsFromPool");

    double thePool = 1000.00;
    Console.WriteLine("The pool is currently ${0}", thePool);
    Console.WriteLine("The original balance of the account instance is ${0}",
                            initialBalance);

    double amountFromPool = 50.00;
    Console.WriteLine("The amount to be subtracted from the pool and added " +
              "to the account is ${0}", amountFromPool);
    
    Console.WriteLine("---");
    Console.WriteLine("Calling {0} ...", myMemberInfo[0].ToString());
    Console.WriteLine("---");

    object[] passMe = new object[] { thePool, amountFromPool };
    Console.WriteLine("The new balance in the account instance is ${0}",
                    custType.InvokeMember("AddFundsFromPool",
                    BindingFlags.InvokeMethod,
                    null, custObj, passMe));
    thePool = (double)passMe[0];
    Console.WriteLine("The new amount in the pool is ${0}", thePool);
   }
}

Imports System.Threading
Imports System.Reflection
Imports System.Reflection.Emit

 _

Class ParamBuilderDemo
   
   Public Shared Function BuildCustomerDataType() As Type
      
      Dim myDomain As AppDomain = Thread.GetDomain()
      Dim myAsmName As New AssemblyName()
      myAsmName.Name = "MyDynamicAssembly"
      
      Dim myAsmBuilder As AssemblyBuilder = myDomain.DefineDynamicAssembly(myAsmName, _
                        AssemblyBuilderAccess.Run)
      
      Dim myModBuilder As ModuleBuilder = myAsmBuilder.DefineDynamicModule("MyMod")
      
      Dim myTypeBuilder As TypeBuilder = myModBuilder.DefineType("CustomerData", TypeAttributes.Public)
      
      Dim customerNameBldr As FieldBuilder = myTypeBuilder.DefineField("customerName", _
                                GetType(String), _
                                FieldAttributes.Private)
      Dim acctIDBldr As FieldBuilder = myTypeBuilder.DefineField("acctID", _
                                GetType(String), _
                                FieldAttributes.Private)
      Dim balanceAmtBldr As FieldBuilder = myTypeBuilder.DefineField("balanceAmt", _
                                GetType(Double), _
                                FieldAttributes.Private)
      
      Dim myCtorBuilder As ConstructorBuilder = myTypeBuilder.DefineConstructor(MethodAttributes.Public, _
                                CallingConventions.HasThis, _
                                New Type() {GetType(String), _
                                        GetType(String), _
                                        GetType(Double)})
      
      
      Dim ctorIL As ILGenerator = myCtorBuilder.GetILGenerator()
      
      Dim objType As Type = Type.GetType("System.Object")
      Dim objCtor As ConstructorInfo = objType.GetConstructor(New Type(){})
      
      ctorIL.Emit(OpCodes.Ldarg_0)
      ctorIL.Emit(OpCodes.Call, objCtor)
      
      ctorIL.Emit(OpCodes.Ldarg_0)
      ctorIL.Emit(OpCodes.Ldarg_1)
      ctorIL.Emit(OpCodes.Stfld, customerNameBldr)
      
      ctorIL.Emit(OpCodes.Ldarg_0)
      ctorIL.Emit(OpCodes.Ldarg_2)
      ctorIL.Emit(OpCodes.Stfld, acctIDBldr)
      
      ctorIL.Emit(OpCodes.Ldarg_0)
      ctorIL.Emit(OpCodes.Ldarg_3)
      ctorIL.Emit(OpCodes.Stfld, balanceAmtBldr)
      
      ctorIL.Emit(OpCodes.Ret)
      
      ' This method will take an amount from a static pool and add it to the balance.
      ' Note that we are passing the first parameter, fundsPool, by reference. Therefore,
      ' we need to inform the MethodBuilder to expect a ref, by declaring the first
      ' parameter's type to be System.Double& (a reference to a double).

      Dim myMthdBuilder As MethodBuilder = myTypeBuilder.DefineMethod("AddFundsFromPool", _
                                MethodAttributes.Public, _
                                GetType(Double), _
                                New Type() {Type.GetType("System.Double&"), _
                                         GetType(Double)})
      
      Dim poolRefBuilder As ParameterBuilder = myMthdBuilder.DefineParameter(1, _
                            ParameterAttributes.Out, "fundsPool")
      
      Dim amountFromPoolBuilder As ParameterBuilder = myMthdBuilder.DefineParameter(2, _
                            ParameterAttributes.In, "amountFromPool")
      
      Dim mthdIL As ILGenerator = myMthdBuilder.GetILGenerator()
      
      mthdIL.Emit(OpCodes.Ldarg_1)
      mthdIL.Emit(OpCodes.Ldarg_1)
      mthdIL.Emit(OpCodes.Ldind_R8)
      mthdIL.Emit(OpCodes.Ldarg_2)
      mthdIL.Emit(OpCodes.Sub)
      
      mthdIL.Emit(OpCodes.Stind_R8)
      
      mthdIL.Emit(OpCodes.Ldarg_0)
      mthdIL.Emit(OpCodes.Ldarg_0)
      mthdIL.Emit(OpCodes.Ldfld, balanceAmtBldr)
      mthdIL.Emit(OpCodes.Ldarg_2)
      mthdIL.Emit(OpCodes.Add)
      
      mthdIL.Emit(OpCodes.Stfld, balanceAmtBldr)
      
      mthdIL.Emit(OpCodes.Ldarg_0)
      mthdIL.Emit(OpCodes.Ldfld, balanceAmtBldr)
      mthdIL.Emit(OpCodes.Ret)
      
      Return myTypeBuilder.CreateType()

   End Function 'BuildCustomerDataType
    
   
   Public Shared Sub Main()

      Dim custType As Type = Nothing
      Dim custObj As Object = Nothing
      
      Dim custArgTypes() As Type = {GetType(String), GetType(String), GetType(Double)}
      
      ' Call the method to build our dynamic class.
      custType = BuildCustomerDataType()
      
      Console.WriteLine("---")
      
      Dim myCustCtor As ConstructorInfo = custType.GetConstructor(custArgTypes)
      Dim initialBalance As Double = 100.0
      custObj = myCustCtor.Invoke(New Object() {"Joe Consumer", "5678-XYZ", initialBalance})
      
      Dim myMemberInfo As MemberInfo() = custType.GetMember("AddFundsFromPool")
      
      
      Dim thePool As Double = 1000.0
      Console.WriteLine("The pool is currently ${0}", thePool)
      Console.WriteLine("The original balance of the account instance is ${0}", initialBalance)
      
      Dim amountFromPool As Double = 50.0
      Console.WriteLine("The amount to be subtracted from the pool and added " & _
            "to the account is ${0}", amountFromPool)
      
      Console.WriteLine("---")
      Console.WriteLine("Calling {0} ...", myMemberInfo(0).ToString())
      Console.WriteLine("---")
      
      Dim passMe() As Object = {thePool, amountFromPool}
      Console.WriteLine("The new balance in the account instance is ${0}", _
                custType.InvokeMember("AddFundsFromPool", _
                BindingFlags.InvokeMethod, Nothing, custObj, passMe))
      thePool = CDbl(passMe(0))
      Console.WriteLine("The new amount in the pool is ${0}", thePool)

   End Sub

End Class

Commenti

Gli attributi dei parametri devono essere coerenti con la firma del metodo. Se si specificano Out attributi per un parametro, è necessario assicurarsi che il tipo del parametro del metodo sia un ByRef tipo.

Per ParameterBuilder il corretto funzionamento del linguaggio MSIL (Microsoft Intermediate Language) in fase di esecuzione, è necessario che alcuni attributi vengano chiamati DefineMethod con parametri praticabili. Ad esempio, se si definisce un ParameterBuilder oggetto con ParameterAttributes.Out per il parametro 1 di MethodBuilder, il parametro 1 di MethodBuilder deve essere un riferimento, ad esempio Type.GetType("System.String&"), anziché Type.GetType("System.String").

Costruttori

ParameterBuilder()

Inizializza una nuova istanza della classe ParameterBuilder.

Proprietà

Attributes	Recupera gli attributi per questo parametro.
IsIn	Specifica se si tratta di un parametro di input.
IsOptional	Specifica se si tratta di un parametro facoltativo.
IsOut	Specifica se si tratta di un parametro di output.
Name	Recupera il nome di questo parametro.
Position	Recupera la posizione della firma per questo parametro.

Metodi

Equals(Object)	Determina se l'oggetto specificato è uguale all'oggetto corrente. (Ereditato da Object)
GetHashCode()	Funge da funzione hash predefinita. (Ereditato da Object)
GetType()	Ottiene l'oggetto Type dell'istanza corrente. (Ereditato da Object)
MemberwiseClone()	Crea una copia superficiale dell'oggetto Object corrente. (Ereditato da Object)
SetConstant(Object)	Imposta il valore predefinito del parametro.
SetCustomAttribute(ConstructorInfo, Byte[])	Imposta un attributo personalizzato usando un BLOB di attributi personalizzati specificato.
SetCustomAttribute(CustomAttributeBuilder)	Impostare un attributo personalizzato usando un generatore di attributi personalizzati.
SetCustomAttributeCore(ConstructorInfo, ReadOnlySpan<Byte>)	Quando ne viene eseguito l'override in una classe derivata, imposta un attributo personalizzato su questo assembly.
ToString()	Restituisce una stringa che rappresenta l'oggetto corrente. (Ereditato da Object)