c++/cli 中 FileSystemEventHandler 的附加参数

Question

我想在 c++/cli 中转换此代码（c# 中的工作代码）

        static private void onChange(object s, FileSystemEventArgs e, string customArg)
    {
        Console.WriteLine(e.FullPath);
        Console.WriteLine(customArg);
    }

    static void Main(string[] args)
    {
        string customArg = "myCustomArg";

        FileSystemWatcher watcher = new FileSystemWatcher();
        watcher.Path = "G:\";
        watcher.IncludeSubdirectories = true;
        watcher.NotifyFilter = NotifyFilters.LastWrite;
        watcher.EnableRaisingEvents = true;

        // i cannot convert this line in c++/cli
        watcher.Changed += (s, e) => onChange(s, e, customArg);

        Console.Read();
    }

我的代码在 c++/cli 中

void FileWatcher::onChanged(Object^ source, FileSystemEventArgs^ e, String^ customArg)
{
   Console::WriteLine(e->FullPath);
   Console::WriteLine(customArg);
}

int main(int argc, char* argv[])
{
   FileSystemWatcher watcher->Path = "G:\";
   watcher->IncludeSubdirectories = true;
   watcher->NotifyFilter = static_cast<System::IO::NotifyFilters>    (NotifyFilters::LastWrite);

   String^ customArg = gcnew String("myArg");

   // this line not compile
   watcher->Changed += (s, e) = > onChange(s, e, customArg);
   //
}

我试过像这样使用 lambda 函数

watcher->Changed += [](Object^ s, FileSystemEventArgs^ e, String^ c) -> void { OnChange(s, e, c); };

但它不起作用，可能是做错了

Answer 1

您似乎无法通过 lambda 执行此操作，因此您必须制作一个 class 来充当事件处理程序，类似于此。

#using <System.dll>

using namespace System;
using namespace System::IO;

void GlobalOnChanged(Object^ source, FileSystemEventArgs^ e, String^ customArg)
{
    Console::WriteLine(e->FullPath);
    Console::WriteLine(customArg);
}

public ref class Invoker
{
public:
    Invoker(String^ customArg) : customArg_(customArg)
    {

    }
    void OnChanged(Object^ source, FileSystemEventArgs^ e)
    {
        GlobalOnChanged(source, e, customArg_);
    }

private:
    String^ customArg_;
};

int main(int argc, char* argv[])
{
    FileSystemWatcher^ watcher = gcnew FileSystemWatcher;
    watcher->Path = "C:\";
    watcher->IncludeSubdirectories = true;
    watcher->NotifyFilter = static_cast<System::IO::NotifyFilters>    (NotifyFilters::LastWrite);
    String^ customArg = gcnew String("myArg");
    watcher->Changed += gcnew FileSystemEventHandler(gcnew Invoker(customArg), &Invoker::OnChanged);
}

c++/cli 中 FileSystemEventHandler 的附加参数

Additional parameters for FileSystemEventHandler in c++/cli

.net

c++-cli