DllImportAttribute.CallingConvention Bidang

Definisi

Ruang nama:

System.Runtime.InteropServices

Rakitan:

System.Runtime.InteropServices.dll

Sumber:

DllImportAttribute.cs

Menunjukkan konvensi panggilan titik masuk.

public: System::Runtime::InteropServices::CallingConvention CallingConvention;

public System.Runtime.InteropServices.CallingConvention CallingConvention;

val mutable CallingConvention : System.Runtime.InteropServices.CallingConvention

Public CallingConvention As CallingConvention 

Nilai Bidang

CallingConvention

Contoh

Dalam beberapa kasus, pengembang Visual Basic menggunakan DllImportAttribute, alih-alih Declare pernyataan , untuk menentukan fungsi DLL dalam kode terkelola. CallingConvention Mengatur bidang adalah salah satu kasus tersebut.

using namespace System;
using namespace System::Runtime::InteropServices;

private ref class NativeMethods
{
    // Managed class methods don't support varargs so all arguments must be
    // explicitly defined. CallingConvention.Cdecl must be used since the
    // stack is cleaned up by the caller.
    // int printf(const char *format [, argument]...)
public:
    [DllImport("msvcrt.dll", CharSet = CharSet::Ansi,
        CallingConvention = CallingConvention::Cdecl)]
    static int printf(String^ format, int i, double d);

    [DllImport("msvcrt.dll", CharSet = CharSet::Ansi,
        CallingConvention = CallingConvention::Cdecl)]
    static int printf(String^ format, int i, String^ s);
};

void main()
{
    NativeMethods::printf("\nPrint params: %i %f", 99, 99.99);
    NativeMethods::printf("\nPrint params: %i %s", 99, "abcd");
}

using System;
using System.Runtime.InteropServices;

internal static class NativeMethods
{
    // C# doesn't support varargs so all arguments must be explicitly defined.
    // CallingConvention.Cdecl must be used since the stack is
    // cleaned up by the caller.
    // int printf(const char *format [, argument]...)
    [DllImport("msvcrt.dll", CharSet = CharSet.Ansi,
        CallingConvention = CallingConvention.Cdecl)]
    internal static extern int printf(string format, int i, double d);

    [DllImport("msvcrt.dll", CharSet = CharSet.Ansi,
        CallingConvention = CallingConvention.Cdecl)]
    internal static extern int printf(string format, int i, string s);
}

public class App
{
    public static void Main()
    {
        NativeMethods.printf("\nPrint params: %i %f", 99, 99.99);
        NativeMethods.printf("\nPrint params: %i %s", 99, "abcd");
    }
}

Imports System.Runtime.InteropServices

Friend Class NativeMethods
    ' Visual Basic doesn't support varargs so all arguments must be explicitly defined.
    ' CallingConvention.Cdecl must be used since the stack is
    ' cleaned up by the caller.
    ' int printf(const char *format [, argument]...)
    <DllImport("msvcrt.dll", CharSet:=CharSet.Ansi,
        CallingConvention:=CallingConvention.Cdecl)>
    Friend Shared Function printf(format As String, i As Integer, d As Double) As Integer
    End Function
    <DllImport("msvcrt.dll", CharSet:=CharSet.Ansi,
        CallingConvention:=CallingConvention.Cdecl)>
    Friend Shared Function printf(format As String, i As Integer, s As String) As Integer
    End Function
End Class

Public Class App
    Public Shared Sub Main()
        NativeMethods.printf(vbCrLf + "Print params: %i %f", 99, 99.99)
        NativeMethods.printf(vbCrLf + "Print params: %i %s", 99, "abcd")
    End Sub
End Class

Keterangan

Anda mengatur bidang ini ke salah CallingConvention satu anggota enumerasi. Nilai default untuk CallingConvention bidang adalah Winapi, yang pada gilirannya default ke StdCall konvensi di Windows, dan Cdecl pada semua platform lainnya.

Lihat juga

• CallingConvention