Question

假设表格上有4个按钮;每隔5秒，这些按钮的背景颜色会随机变化（但它也可以保持不变）我怎么才能得到改变背景的按钮？

List<Button> oldList;
        oldList = new List<Button>();
        foreach (Button item in Controls.OfType<Button>())
        {
            //First we catch all the buttons' instances at for e.g 12:00
            oldList.Add(item);
        }

        buttonsChangeColor(); //Five seconds later some buttons change their bg color

        List<Button> newList = new List<Button>();
        foreach (Button item in Controls.OfType<Button>())
        {
            //2nd we catch all the buttons' instances at for e.g 12:05 after some of theme changed color
            newList.Add(item);
        }

        //HOW CAN I COMPARE THESE 2 LISTS BASED ON THE BACKGROUNDCOLOR ? If it has changed or not

Answer 1

这应该有效

var changed = oldList.Zip(newList, (old, new) => new { Old = old, New = new })
                     .Where(old.BackColor != new.BackColor);

Enumerable.Zip按元素对两个集合进行对。如果您只修改了颜色，则订单不应更改 - 因此就足够了。

Answer 2

由于oldList和newList中按钮的实例相同，因此您需要记住旧背景颜色，以便将它们与新背景颜色进行比较。

以下内容应该有效：

var oldList = Controls.OfType<Button>().ToDictionary(btn => btn, btn => btn.BackColor);
buttonsChangeColor();
var changedBackgrounds = Controls.OfType<Button>()
    .Where(btn => oldList[btn] != btn.BackColor).ToList();

比较基于属性的两个List <control>之前/之后

2 个答案: