我m creating a custom wrap panel which will contain a grid inside. The Custom panel will be an ItemsPanelTemplate for the groups of my gridview. What i做的是我将所有的GridViewItem存储在网格中，并且唯一的子节点将是网格或其他网格，如果项目不t fit in the current one(custom logic for placing items based on rowspan and colspan). I m出现问题导致网格。当我在自定义面板中调用grid.Measure（availableSize）时，会为网格调用Measureoverride。我做错了什么？