如何在Xamarin Forms MasterDetailPage项目中一次加载detailpage | asterDetailPage项目中一次加载detailpage

本文介绍了如何在Xamarin Forms MasterDetailPage项目中一次加载detailpage的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我注意到每次选择主页页面菜单项时都会从头开始加载detailpage(因此每次都调用它的构造函数).有没有一种方法可以实现一次加载一次的详细信息页面，因此每次选择菜单项时，都会简单地显示/不显示详细信息页面?

I noticed detailpage is loaded from scratch everytime masterpage menu item is selected (so its constructor is called everytime).Is there a way to implement a detailpage which is loaded once, so everytime menu item is selected detailpage is simply showed/not showed?

谢谢，刘易斯

推荐答案

我解决了在MasterDetailPage中实现字典页面缓存的问题:

I solved implementing a dictionary page cache in MasterDetailPage:

// in constructor
MasterPageMenuCache = new Dictionary<Type, Page>();

// in OnItemSelected
if (MasterPageMenuCache.Count == 0)
    MasterPageMenuCache.Add(typeof(FirstDefaultDetailPage), Detail);

var item = e.SelectedItem as MasterPageItem;
if (item != null)
{
    if (MasterPageMenuCache.ContainsKey(item.TargetType))
    {
        Detail = MasterPageMenuCache[item.TargetType];
    }
    else
    {
        Detail = new NavigationPage((Page)Activator.CreateInstance(item.TargetType));
        MasterPageMenuCache.Add(item.TargetType, Detail);
    }

    masterPage.ListView.SelectedItem = null;
    IsPresented = false;
}

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