c# - WPF WrapPanel 动态高度

Question

我有一个包含可变数量控件的包装面板。

我希望方向是垂直的(因为其中的对象将具有固定宽度但可变高度)。

但我遇到的问题是，当存在滚动条时，高度是无限的，因此项目永远不会换行到第二列。滚动条是必需的，因为经常会有更多的对象超过一个屏幕上可能容纳的对象。我可以通过设置固定高度来阻止这种情况，但这不是一个可接受的解决方案，因为每个选择的合理固定高度都会有所不同。

基本上我想要一个WrapPanel，它的高度根据面板的宽度和其中包含的项目数量动态变化。

举例说明:

如果面板足够宽以显示 3 列，它将:

| 1 5 9 |

| 2 6 - |

| 3 7 - |高度=4

| 4 8 - |

但是如果用户将窗口的大小更改为只能容纳 2 列的高度将会增加:

| 1 6 |

| 2 7 |

| 3 8 |高度 = 5

| 4 9 |

| 5 - |

此外，我不确定这有多可行，但理想情况下我希望水平排列元素但保持垂直方向，这样它们就会被排列:

| 1 2 3 |

| 4 5 6 |

| 7 8 9 |

谁能告诉我如何开始使用它？我假设 WrapPanel 的自定义实现是可能的，但我对如何开始有点困惑。

谢谢，

Answer 1

设法通过以下代码实现我所需要的:

public class InvertedWrapPanel : WrapPanel
{
    private int itemsPerRow = 0;

    protected override Size MeasureOverride(Size availableSize)
    {
        if (Orientation == Orientation.Horizontal)
        {
            return base.MeasureOverride(availableSize);
        }
        else //Orientation is vertical
        {
            double w = availableSize.Width;

            double maxChildWidth = 0;

            foreach (UIElement child in Children)
            {
                //Get the current childs desired size parameters
                child.Measure(availableSize);

                //Store off the maximum child width
                if (child.DesiredSize.Width > maxChildWidth)
                    maxChildWidth = child.DesiredSize.Width;
            }

            //See how many items we can fit in a row
            itemsPerRow = Convert.ToInt32(Math.Floor(w / maxChildWidth));

            return base.MeasureOverride(availableSize);
        }
    }

    protected override Size ArrangeOverride(Size finalSize)
    {
        if (Orientation == Orientation.Horizontal)
        {
            return base.ArrangeOverride(finalSize);
        }
        else //Orientation is vertical
        {
            double currentX = 0;
            double currentY = 0;

            int col = 0;

            double lastX = 0;
            double lastWidth = 0;

            //Arrays to store differing column heights
            double[] lastY = new double[itemsPerRow];
            double[] lastHeight = new double[itemsPerRow];

            double[] colHeights = new double[itemsPerRow];

            foreach (UIElement child in Children)
            {
                //If we've reached the end of a row
                if (col >= itemsPerRow)
                {
                    col = 0;
                    currentX = 0; //reset the x-coordinate for first column
                }
                else
                    currentX = lastX + lastWidth; //Increase the x-coordinate

                //Increase the y-coordinates for the current column
                currentY = lastY[col] + lastHeight[col];

                //Draw the element
                child.Arrange(new Rect(currentX, currentY, child.DesiredSize.Width, child.DesiredSize.Height));

                //Store off the current child's parameters
                lastX = currentX;
                lastWidth = child.DesiredSize.Width;

                lastY[col] = currentY;
                lastHeight[col] = child.DesiredSize.Height;

                colHeights[col] += child.DesiredSize.Height;

                col++;
            }

            //Set the height of the panel to the max column height.
            //Otherwise scroll bar will set height to infinity.
            double maxHeight = 0;

            foreach (double d in colHeights)
            {
                if (d > maxHeight)
                    maxHeight = d;
            }

            base.Height = maxHeight;

            return finalSize;
        }
    }