在实际项目中，需要获取实时数据并画图，本实例开发出可画图控件，能方便显示数据，并且随鼠标移动实时显示坐标点数据-In the actual project, it is necessary to obtain real-time data, and drawing, this example may be drawing to develop control, can easily display data, and real-time display with the mouse coord