如何在绘制事件中保留以前的图形?

本文介绍了如何在绘制事件中保留以前的图形?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我正在使用e.Graphics.FillEllipse(Brushes.Red, ph1.X,ph1.Y, 20, 20);在panel1_Paint 事件中绘制一个椭圆.点 ph1 值来自 textbox_KeyPress.in the panel1_Paint event to draw an ellipse. The point ph1 value comes from textbox_KeyPress.我还在 textbox_KeyPress 事件中添加了 panel1.Invalidate(); 以强制在 panel1 上重绘.它正在做的是清除 panel1 然后添加新图形.I also added panel1.Invalidate(); in the textbox_KeyPress event to force redraw on panel1. What it is doing is clearing panel1 then add the new graphics. 我真正想让它做的是在不清除以前的图形的情况下添加新图形. 有什么方法吗?推荐答案最简单的方法是创建一个有序的对象集合(例如 List)，每次调用 OnPaint 事件时都会重绘这些对象.The simplest way is for you to create an ordered collection of objects (a List<> for example) which you would redraw each time that the OnPaint event is called.类似于: // Your painting class. Only contains X and Y but could easily be expanded // to contain color and size info as well as drawing object type. class MyPaintingObject { public int X { get; set; } public int Y { get; set; } } // The class-level collection of painting objects to repaint with each invalidate call private List<MyPaintingObject> _paintingObjects = new List<MyPaintingObject>(); // The UI which adds a new drawing object and calls invalidate private void button1_Click(object sender, EventArgs e) { // Hardcoded values 10 & 15 - replace with user-entered data _paintingObjects.Add(new MyPaintingObject{X=10, Y=15}); panel1.Invalidate(); } private void panel1_Paint(object sender, PaintEventArgs e) { // loop through List<> and paint each object foreach (var mpo in _paintingObjects) e.Graphics.FillEllipse(Brushes.Red, mpo.X, mpo.Y, 20, 20); } 这篇关于如何在绘制事件中保留以前的图形?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！