Question

我想在3个表单上绘制很多行但是当我调用这个方法时，需要花费很多时间。 200多行，大约需要1秒。我做错了什么？

public void drawObjects()
{
    pAux = selectedPen;
    for (int i = 0; i < objects.Count; i++)
    {
        for(int ed = 0; ed < objects[i].getEdges().Count; ed++)
        {
            frontGraphics.DrawRectangle(recPen, (objects[i].getEdges()[ed].getPoint1().X + 332), -(objects[i].getEdges()[ed].getPoint1().Y - 170), 2, 2);
            rightGraphics.DrawRectangle(recPen, objects[i].getEdges()[ed].getPoint1().Z + 332, -(objects[i].getEdges()[ed].getPoint1().Y - 170), 2, 2);
            topGraphics.DrawRectangle(recPen, objects[i].getEdges()[ed].getPoint1().X + 332, -(objects[i].getEdges()[ed].getPoint1().Z - 170), 2, 2);

            if (objects[i].getEdges().Count > 0)
            {
                if (objects[i].selected == true)
                    pAux = selectedPen;
                else
                    pAux = linePen;
                frontGraphics.DrawLine(pAux, objects[i].getEdges()[ed].getPoint1().X + 332, -(objects[i].getEdges()[ed].getPoint1().Y -170), 
                                           objects[i].getEdges()[ed].getPoint2().X + 332, -(objects[i].getEdges()[ed].getPoint2().Y -170));
                rightGraphics.DrawLine(pAux, objects[i].getEdges()[ed].getPoint1().Z + 332, -(objects[i].getEdges()[ed].getPoint1().Y - 170),
                                            objects[i].getEdges()[ed].getPoint2().Z + 332, -(objects[i].getEdges()[ed].getPoint2().Y - 170));
                topGraphics.DrawLine(pAux, objects[i].getEdges()[ed].getPoint1().X + 332, -(objects[i].getEdges()[ed].getPoint1().Z - 170),
                                           objects[i].getEdges()[ed].getPoint2().X + 332, -(objects[i].getEdges()[ed].getPoint2().Z - 170));

            }
        }          
    }
}

Answer 1

目前尚不清楚您正在使用的前端（WPF，WinForms），但您可能会在当前代码中使用大量资源。 getEdges()和/或getPoint()方法可能是昂贵的方法，您可以将这些方法称为很多。

如果您要重用方法的结果：将其存储在变量中。这是您的代码的样子：

public void drawObjects()
{
    pAux = selectedPen;
    for (int i = 0; i < objects.Count; i++)
    {
        var currentObject = objects[i];
        var edges = currentObject.getEdges();

        for(int ed = 0; ed < edges.Count; ed++)
        {
            var currentEd = edges[ed];
            var edPoint1 = currentEd.getPoint1();
            var edPoint2 = currentEd.getPoint2();

            frontGraphics.DrawRectangle(recPen, (edPoint1.X + 332), -(edPoint1.Y - 170), 2, 2);
            rightGraphics.DrawRectangle(recPen, edPoint1.Z + 332, -(edPoint1.Y - 170), 2, 2);
            topGraphics.DrawRectangle(recPen, edPoint1.X + 332, -(edPoint1.Z - 170), 2, 2);

            pAux = currentObject.selected ? selectedPen : linePen;

            frontGraphics.DrawLine(pAux, edPoint1().X + 332, -(edPoint1().Y -170), edPoint2.X + 332, -(edPoint2.Y -170));
            rightGraphics.DrawLine(pAux, edPoint1.Z + 332, -(edPoint1.Y - 170), edPoint2.Z + 332, -(edPoint2.Y - 170));
            topGraphics.DrawLine(pAux, edPoint1.X + 332, -(edPoint1.Z - 170), edPoint2.X + 332, -(edPoint2.Z - 170));
        }          
    }
}

编辑，如@Hans Kesting所述，内循环中的这一行是多余的：

if (objects[i].getEdges().Count > 0)

自从你进入内循环后，它将始终评估为true。

PS：请注意，这可能无法解决您的所有性能问题，但我相信这会有所帮助。

Answer 2

我使用PICTURE BOX解决了这个问题，我在一个位图中绘制并将位图设置为图片框的图像。

绘制很多线条非常慢

2 个答案: