Question

我的c＃winform项目有问题。

在我的项目中，我有一个功能，可以将按钮的位置切换到旧位置，如果它们位于同一区域。

private void myText_MouseUp（object sender，MouseEventArgs e） {

Point q = new Point(0, 0);
        Point q2 = new Point(0, 0);
        bool flag = false;
        int r = 0;
        foreach (Control p in this.Controls)
        {
            for (int i = 0; i < counter; i++)
            {
                if (flag)
                {
                    if (p.Location.X == locationx[i] && p.Location.Y == locationy[i])
                    {
                        oldx = e.X;
                        oldy = e.Y;
                        flag = true;
                        r = i;
                    }
                }
            }
        }
        foreach (Control p in this.Controls)
        {
            for (int j = 0; j < counter; j++)
            {
                if ((locationx[j] == p.Location.X) && (locationy[j] == p.Location.Y))
                {
                    Point arrr = new Point(oldx, oldy);
                    buttons[j].Location = arrr;
                    buttons[r].Location = new Point(locationx[j], locationy[j]);
                }
            }
        }
}
   The problem with this code is that if they are in the same area, the buttons do not switch their locations.  Instead they goes to the last button location.

如果有人可以帮助我，那将有助于我：）

Answer 1

if语句始终求值为true。这意味着最终的j循环将执行此操作：

// last time round the i loop, i == counter-1
// and q == new Point(locationx[counter-1], locationy[counter-1])
for (int j = 0; j < counter; j++)
{
    Point q2 = new Point(locationx[j], locationy[j]);
    buttons[i].Location = q2;
    buttons[j].Location = q;
}

最终结果是每个按钮的Location都设置为q，这是

new Point(locationx[counter-1], locationy[counter-1])

为什么if语句始终评估为true。好吧，首先让我们看一下or语句中的几个if子句：

|| ((q.Y >= q2.Y) && (q.X <= q2.X))
|| ((q.Y >= q2.Y) && (q.X == q2.X))

这相当于

|| ((q.Y >= q2.Y) && (q.X <= q2.X))

包含==测试的行对条件的最终结果完全没有影响。事实上，包含==的所有行都可以进行类似的处理。这留下了：

|| ((q.Y >= q2.Y) && (q.X <= q2.X))
|| ((q.Y >= q2.Y) && (q.X >= q2.X))
|| ((q.Y <= q2.Y) && (q.X >= q2.X))
|| ((q.Y <= q2.Y) && (q.X <= q2.X))

我们可以压缩

|| ((q.Y >= q2.Y) && (q.X <= q2.X))
|| ((q.Y >= q2.Y) && (q.X >= q2.X))

进入

|| ((q.Y >= q2.Y)

和类似的

|| ((q.Y <= q2.Y) && (q.X >= q2.X))
|| ((q.Y <= q2.Y) && (q.X <= q2.X))

与

相同

|| ((q.Y <= q2.Y)

联合

|| ((q.Y >= q2.Y)
|| ((q.Y <= q2.Y)

您可以看到if条件始终评估为true。

替换按钮位置

1 个答案: