DllImportAttribute.CallingConvention Veld

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

public System.Runtime.InteropServices.CallingConvention CallingConvention;

val mutable CallingConvention : System.Runtime.InteropServices.CallingConvention

Public CallingConvention As CallingConvention 

Waarde van veld

Voorbeelden

In sommige gevallen gebruiken Visual Basic ontwikkelaars de DllImportAttribute in plaats van de instructie Declare om een DLL-functie in beheerde code te definiëren. Het instellen van het CallingConvention veld is een van deze gevallen.

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

Opmerkingen

U stelt dit veld in op een van de CallingConvention opsommingsleden. De standaardwaarde voor het veld CallingConvention is Winapi, die op zijn beurt standaard de conventie StdCall op Windows en Cdecl op alle andere platforms.

Zie ook

• CallingConvention