索引到ArrayList的结果的InvalidCastException

Question

我有一个ArrayList填充了一堆点,我想循环它们,所以我使用这个代码:

for (int i = 0; i < currentClicks.Count; i++)
{
    if (i > 0) // Skip the first click
    {
        clickPos = currentClicks[i];
        prevPos = currentClicks[i - 1];
    }
}

我在clickPos和prevPos线上得到这个错误:

Cannot implicitly convert type 'object' to 'System.Drawing.Point'.
An explicit conversion exists (are you missing a cast?)

为什么是这样？我有clickPos并prevPos定义如下:

private System.Drawing.Point clickPos;
private System.Drawing.Point prevPos;

编辑

当我注释掉clickPos和prevPos线并添加

MessageBox.Show(currentClicks[i].GetType().ToString());

消息框说 System.Drawing.Point

Answer 1

你应该使用泛型List<Point>而不是ArrayList.

如果您坚持使用ArrayList,则需要Point在检索时将对象强制转换为a :

clickPos = (Point)currentClicks[i];