您可以做的是:

private Thread tMethod1 = new Thread(runMethod1);
private Thread tMethod2 = new Thread(runMethod2);
private Thread tMethod3 = new Thread(runMethod3);


private void runThreads();
{
    tMethod1.Start(); //starts method 1
    tMethod2.Start(); //starts method 2
    tMethod1.Join();  //waits for method 1 to finish
    tMethod2.Join();  //waits for method 2 to finish
    tMethod3.Start(); //starts method 3
    tMethod3.Join();  //waits for method 3 to finish
}

private void runMethod1()
{
    Method1();
}
private void runMethod2()
{
    Method2();
}
private void runMethod3()
{
    Method3();
}

这将同时运行Method1和Method2，并在Method3启动之前等待它们完成.
可以解决一些问题，但是可以.

This will run Method1 and Method2 simultaniously and waits for those to finish before the Method3 is started.
It's a little work around, but works.