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FieldBuilder.SetOffset(Int32) Метод

Определение

Устанавливает расположение поля.

C#
public void SetOffset(int iOffset);

Параметры

iOffset
Int32

Смещение поля внутри содержащего это поле типа.

Исключения

Содержащий тип был создан с помощью CreateType().

Значение параметра iOffset меньше нуля.

Комментарии

В следующем примере кода показано использование SetOffset.

C#
using System;
using System.Runtime.InteropServices;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;
using System.Security.Permissions;
using System.Runtime.CompilerServices;

public class FieldBuilder_Sample
{
   public static Type CreateType(AppDomain currentDomain)
   {
      // Create an assembly.
      AssemblyName myAssemblyName = new AssemblyName();
      myAssemblyName.Name = "DynamicAssembly";
      AssemblyBuilder myAssembly =
         currentDomain.DefineDynamicAssembly(myAssemblyName,AssemblyBuilderAccess.RunAndSave);
      // Create a dynamic module in Dynamic Assembly.
      ModuleBuilder myModuleBuilder=myAssembly.DefineDynamicModule("MyModule","MyModule.mod");
      // Define a public class named "MyClass" in the assembly.
      TypeBuilder myTypeBuilder= myModuleBuilder.DefineType("MyClass",TypeAttributes.Public);
      TypeBuilder myTypeBuilder2 = myModuleBuilder.DefineType("MyClass2",
         TypeAttributes.Public|TypeAttributes.BeforeFieldInit|TypeAttributes.SequentialLayout|TypeAttributes.AnsiClass|TypeAttributes.Sealed);
      FieldBuilder myFieldBuilder1= myTypeBuilder2.DefineField("myBytes1",
                                    typeof(byte),FieldAttributes.Public);
      FieldBuilder myFieldBuilder2= myTypeBuilder2.DefineField("myBytes2",
                                    typeof(byte),FieldAttributes.Public);
      FieldBuilder myFieldBuilder3= myTypeBuilder2.DefineField("myErrorCode",
                                    typeof(short),FieldAttributes.Public);
      FieldBuilder myFieldBuilder4= myTypeBuilder2.DefineField("myReserved1",
                                    typeof(short),FieldAttributes.Public);
      FieldBuilder myFieldBuilder5= myTypeBuilder2.DefineField("myReserved2",
                                    typeof(short),FieldAttributes.Public);
      FieldBuilder myFieldBuilder6= myTypeBuilder2.DefineField("myPathName",
                                    typeof(char[]),FieldAttributes.Public);
      myFieldBuilder6.SetMarshal(UnmanagedMarshal.DefineByValArray(128));
      myFieldBuilder6.SetOffset(4);
      Type myType1 = myTypeBuilder2.CreateType();
      // Create the PInvoke method for 'OpenFile' method of 'Kernel32.dll'.
      Type[] myParameters={ typeof(string), myType1 ,typeof(uint)};
      MethodBuilder myMethodBuilder= myTypeBuilder.DefinePInvokeMethod("OpenFile",
                                     "kernel32.dll",MethodAttributes.Public|MethodAttributes.Static|MethodAttributes.HideBySig,
                                       CallingConventions.Standard,typeof(IntPtr),
                                       myParameters,CallingConvention.Winapi,CharSet.None);
      Type myAttributeType = typeof(MethodImplAttribute);
      ConstructorInfo myConstructorInfo =
         myAttributeType.GetConstructor(new Type[1]{typeof(MethodImplOptions)});
      CustomAttributeBuilder myAttributeBuilder = new CustomAttributeBuilder(myConstructorInfo,
                                                   new object[1]{MethodImplOptions.PreserveSig});
      myMethodBuilder.SetCustomAttribute(myAttributeBuilder);
      ParameterBuilder myParameterBuilder2=myMethodBuilder.DefineParameter(2,
                                            ParameterAttributes.Out,"myClass2");
      Type myType=myTypeBuilder.CreateType();
      myAssembly.Save("EmittedAssembly.dll");
      return myType;
   }

   public static void Main()
   {
      try
      {
         Type myType = CreateType(Thread.GetDomain());
         Type myClass2 = myType.Module.GetType("MyClass2");
         object myParam2 = Activator.CreateInstance(myClass2);
         uint myUint=0x00000800;
         object[] myArgs= {"MyFile.Txt",myParam2,myUint};
         Object myObject  = myType.InvokeMember("OpenFile",BindingFlags.Public |
            BindingFlags.InvokeMethod | BindingFlags.Static,null,null,myArgs);
         Console.WriteLine("MyClass.OpenFile method returned: \"{0}\"", myObject);
      }
      catch(Exception e)
      {
         Console.WriteLine("Exception Caught "+e.Message);
      }
   }
}

Применяется к

Продукт Версии
.NET Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 2.0 (package-provided), 2.1