网格扩展器 [英] Expanders in Grid

问题描述

毫无疑问，这将是直截了当的，但是无论出于何种原因，我的想法都在此空白.

This is going to be straight forward no doubt, but for what ever reason, my mind is drawing a blank on it.

我有一个不可调整大小的小窗口(325x450)，其中有3个扩展器，垂直堆叠.每个扩展器都包含一个ItemsControl，该控件可能包含很多项目，因此需要滚动.

I've got a small, non-resizeable window (325x450) which has 3 Expanders in it, stacked vertically. Each Expander contains an ItemsControl that can potentially have a lot of items in and therefore need to scroll.

我似乎无法正确理解的是如何布置扩展器，以使其扩展以填充可用的任何空间，而无需将其他元素推离屏幕.我可以通过使用Grid并将每个扩展器以*高度排成一行来达到我想要的目的，但是这意味着它们始终占据每个窗口的1/3，这会破坏扩展器的位置:)

What I can't seem to get right is how to layout the Expanders so that they expand to fill any space that is available without pushing other elements off the screen. I can sort of achieve what I'm after by using a Grid and putting each expander in a row with a * height, but this means they are always taking up 1/3 of the window each which defeats the point of the Expander :)

我想要实现的胡扯图:

推荐答案

如果您不介意任何代码隐藏，则可能会陷入Expanded/Collapsed事件，找到父级Grid ，获取扩展器的RowDefinition，并将其值设置为等于*(如果已扩展)，或者等于Auto.

If you don't mind a little code-behind, you could probably hook into the Expanded/Collapsed events, find the parent Grid, get the RowDefinition for the expander, and set the value equal to * if its expanded, or Auto if not.

例如，

Expander ex = sender as Expander;
Grid parent = FindAncestor<Grid>(ex);
int rowIndex = Grid.GetRow(ex);

if (parent.RowDefinitions.Count > rowIndex && rowIndex >= 0)
    parent.RowDefinitions[rowIndex].Height = 
        (ex.IsExpanded ? new GridLength(1, GridUnitType.Star) : GridLength.Auto);

FindAncestor方法的定义如下:

public static T FindAncestor<T>(DependencyObject current)
where T : DependencyObject
{
    // Need this call to avoid returning current object if it is the 
    // same type as parent we are looking for
    current = VisualTreeHelper.GetParent(current);

    while (current != null)
    {
        if (current is T)
        {
            return (T)current;
        }
        current = VisualTreeHelper.GetParent(current);
    };
    return null;
}

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