我尝试使用位图时参数无效

Question

我正在尝试使用 picturebox

创建一个显示在线列车的应用程序

为了实现这一点，我创建了一个worker thread来获得在线列车的位置。所以我在这里定义了线程：

private Thread workerThread = null;
private delegate void UpdateListBoxDelegate();
private UpdateListBoxDelegate UpdateListBox = null;

在Form_load我称之为：

            UpdateListBox = new UpdateListBoxDelegate(this.UpdateStatus);
            // Initialise and start worker thread
            workerThread = new Thread(new ThreadStart(this.GetOnlineTrain));
            workerThread.Start();

我委托处理的方法是：

private void UpdateStatus()
{
    foreach (TimeTable onlineTrain in OnlineTrainList.ToList())
    {
        if (lstSensorLeft.Count != 0 || lstSensorRight.Count != 0)
        {
            pictureBoxonlineTrain.Image = null;

            DrawOnlineTrain();
        }
        else
        {
            pictureBoxonlineTrain.Image = null;
        }
    }

    this.Invalidate();
}

GetOnlineTrain获得在线列车的位置，如您所见：

public void GetOnlineTrain()
{
    try
    {
        while (true)
        {
            TimeTableRepository objTimeTableREpository = new TimeTableRepository();
            OnlineTrainList = objTimeTableREpository.GetAll().ToList();
            objTimeTableREpository = null;
            Invoke(UpdateListBox);
        }
    }
    catch(Exception a)
    {
    }

}

最后的功能是在picturebox上绘制在线列车：

       public void DrawOnlineTrain()
    {
        Bitmap map;
        using (map = new Bitmap(pictureBoxonlineTrain.Size.Width, pictureBoxonlineTrain.Size.Height))
        {
            if (OnlineTrainList.Count > 0)
            {
                using (Graphics graph = Graphics.FromImage(map))
                {
                    foreach (TimeTable t in OnlineTrainList.ToList())
                    {
                        // graph.Dispose();
                        Rectangle rectTrainState = new Rectangle(t.XTrainLocation.Value - 3,
                                                                 t.YTrainLocation.Value - 3,
                                                                 15, 15);
                        graph.FillRectangle(RedBrush, rectTrainState);
                        graph.DrawString(t.TrainId.ToString(), pictureBoxonlineTrain.Font, Brushes.White, t.XTrainLocation.Value - 3, t.YTrainLocation.Value - 3);
                        pictureBoxonlineTrain.Image = map;

                    }
                }
            }
        }


    }

要首次绘制在线列车我在picturebox上绘制了大小为x=A和y=b的列车（线路，车站......）地图，之后我创建了另一个{{ 1}}具有相同的大小，并使用此代码将第二个picturebox放在第一个picturebox上：

picturebox

但是当我在这行中运行我的应用程序时，我在 pictureBoxonlineTrain.Parent = pictureBoxMetroMap; 中获得了Parameter is not valid。

map = new Bitmap（pictureBoxonlineTrain.Size.Width，pictureBoxonlineTrain.Size.Height）;

堆栈跟踪：

DrawOnlineTrain

Answer 1

  

我必须处理因为内存不足异常

不，你必须处理你不再使用的图像。正确的代码是：

   Bitmap map = new Bitmap(pictureBoxonlineTrain.Size.Width, pictureBoxonlineTrain.Size.Height))
   using (Graphics graph = Graphics.FromImage(map)) {
       graph.Clear(this.BackColor);
       foreach (TimeTable t in OnlineTrainList.ToList()) {
           Rectangle rectTrainState = new Rectangle(...);
           graph.FillRectangle(RedBrush, rectTrainState);
           graph.DrawString(...);
       }
   }
   if (pictureBoxonlineTrain.Image != null) pictureBoxonlineTrain.Image.Dispose();
   pictureBoxonlineTrain.Image = map;