怎么用c#实现点击按钮在已经存在的图片上的a(0,0)和b(20,20)之间加上一条红色的线?
答案是转别人的,楼主可以看看。目前对c#也是学习中,一起加油。namespace case02_1{ public partial class form1 : form { int startx; //获取鼠标起始点的x坐标 int starty; //获取鼠标起始点的y坐标 graphics g; //定义graphics对象实例 public form1() { initializecomponent(); } private void form1_load(object sender, eventargs e) { th**.startposition = formstartposition.centerscreen; th**.backcolor = color.snow; } private void form1_mouseup(object sender, mouseeventargs e) { g = th**.creategraphics(); pen p = new pen(color.red , 4); if (radiobutton1.checked == true) { g.drawline(p, startx, starty, e.x, e.y); } } private void form1_mousedown(object sender, mouseeventargs e) { startx = e.x; starty = e.y; } private void form1_mousemove(object sender, mouseeventargs e) { g = th**.creategraphics(); pen p = new pen(color.blue , 2); if (radiobutton2.checked == true) { g.drawrectangle(p, e.x, e.y, 1, 1); } } private void button1_click(object sender, eventargs e) { g = th**.creategraphics(); g.clear(color.snow ); } private void button2_click(object sender, eventargs e) { th**.close(); application.exit()(); } }} 20210311