C# 线程方法名称预期错误

Question

我正在尝试创建一个简单的线程过程(假设这是我第一次尝试线程)，我想要它做的就是对 string[] 中的每个字符串简单地遍历一个 void 并执行简单的文件夹爬行。但是，我收到了预期的方法名称，但我不确定为什么

string[] FileListing = {@"C:\","E:\"};
        foreach (string fl in FileListing)
        {
            ProjectDirectoryProcessing pjp = new ProjectDirectoryProcessing();
            //error here
            Thread oThread = new Thread(new ThreadStart(pjp.ProjectProcessor(fl)));
            oThread.Start();
        }

public class ProjectDirectoryProcessing
{
    public void ProjectProcessor(string rootDirectory)
    {
        Stopwatch stopwatch = new Stopwatch();
        stopwatch.Start();
        HashSet<string> DirectoryHolding = new HashSet<string>();
        //do some work
        //foreach loop
    };
  }

Answer 1

您必须将委托(delegate)传递给线程构造函数。此处最简单的方法是使用 lambda 表达式:

string copy = fl;
Thread oThread = new Thread(() => pjp.ProjectProcessor(copy));

请注意，由于捕获循环变量的方式，您需要复制循环变量。 (有关更多详细信息，请参阅 Eric Lippert's blog post。)

或者，当您在每次迭代中创建新的 ProjectDirectoryProcessing 实例时，您可以将字符串传递给构造函数:

foreach (string fl in FileListing)
{
    // Note change in name to be clearer (IMO)
    ProjectDirectoryProcessor pjp = new ProjectDirectoryProcessor(fl);
    Thread oThread = new Thread(pjp.Execute);
    oThread.Start();
}

...

public class ProjectDirectoryProcessor
{
    private readonly string rootDirectory;

    public ProjectDirectoryProcessor(string rootDirectory)
    {
        this.rootDirectory = rootDirectory;
    }

    public void Execute()
    {
        Stopwatch stopwatch = Stopwatch.StartNew();
        HashSet<string> DirectoryHolding = new HashSet<string>();
        // do some work
        //foreach loop
    }
}