Question

我正在尝试比较两个进程列表并仅获得差异（新启动的进程）。因此，当我单击winform中的按钮时，程序应加载oldProcesses，然后加载newProcesses，在差异和显示差异列表中进行比较。第一次的差异列表应为空，因为oldProcesses和newProcesses是相同的。但它没有发生，问题在于这个代码：var Difference = newProcesses.Except（oldProcesses）.ToList（）; 如何区分newProcesses和oldProcesses？谢谢

    Process[] oldProcesses = { };
    int clicked = 0;

    private void button1_Click_1(object sender, EventArgs e)
    {           
        if (clicked == 0)
        {
            oldProcesses = Process.GetProcesses();            
            clicked = 1;
        }
        Console.WriteLine("Old: " + oldProcesses.Count());

        Process[] newProcesses = Process.GetProcesses();
        Console.WriteLine("New: " + newProcesses.Count());

        var Difference = newProcesses.Except(oldProcesses).ToList();
        Console.WriteLine("Diff: " + Difference.Count());


        string allproc = "";
        foreach(Process theprocess in oldProcesses)
        {
            allproc += theprocess.ProcessName.ToString() +"\n";
        }
        MessageBox.Show(allproc);

        allproc = "";
        foreach (Process theprocess in newProcesses)
        {
            allproc += theprocess.ProcessName.ToString() + "\n";
        }
        MessageBox.Show(allproc);


        allproc = "";
        foreach (Process theprocess in Difference)
        {
            allproc += theprocess.ProcessName.ToString() + "\n";
        }
        MessageBox.Show(allproc);


        /*Process[] processlist = Process.GetProcesses();
        string ProcList = "";
        string temp;
        foreach (Process theprocess in processlist)
        {
            temp = theprocess.ProcessName.ToString() + "\n";
            ProcList += temp;
        }*/
    }

Answer 1

public class ProcessDiff : IEqualityComparer<Process>
{

    public IEnumerable<Process> GetDiff(IEnumerable<Process> oldProcesses, IEnumerable<Process> newProcesses )
    {
        return newProcesses.Except(oldProcesses, this);
    }
    public bool Equals(Process x, Process y)
    {
        if (x == null && y == null) return true;
        if (x == null || y == null) return false;
        return x.Id == y.Id && x.ProcessName == y.ProcessName && x.SessionId == y.SessionId;
    }

    public int GetHashCode(Process obj)
    {
        if (obj == null) return 0;
        return obj.Id;
    }
}

和用法：

        var oldProc = Process.GetProcesses();
        var newProc = Process.GetProcesses();

        var diff = new ProcessDiff().GetDiff(oldProc, newProc);

如果你不想，你实际上不需要为此创建一个单独的类。您也可以创建表单工具IEqualityComparer<Process>并向其添加所需的Equals() / GetHashCode()方法。 Except方法有一个包含比较方法的类实例的参数（如果在包含this方法的同一个类中调用它，则为IEqualityComparer）。

更新：我添加了一些额外的约束，因为Process.Id可以回收。您可能需要根据您的需求来检查其他因素。请记住，Idle进程会在某些属性上抛出异常。

C＃ - 查找两个Process类型列表之间的差异

1 个答案: