显示后将元素添加到 MonoTouch 对话框 RootElement 时出现奇怪的块 [英] Weird blocks when adding Elements to MonoTouch Dialog RootElement after it is shown

问题描述

在我正在构建的应用程序中，我使用以下模式:如果用户单击分层导航元素，我会立即打开下一个 UIViewController，它会自行加载数据并显示一个如果通过网络加载微调器.

In an app I am building I use the following pattern: If the user clicks on a hierarchical navigation element I open the next UIViewController immediately, and it takes care about loading its data itself and shows a loading spinner if it is going over the network.

现在大多数列表视图都是使用 MonoTouch 创建的.在一个 DialogViewController 上，我在屏幕已经显示后向视图 RootElement 添加许多元素时遇到问题.

Now most list views are created using MonoTouch. On one DialogViewController I have an issue with adding many element to the views RootElement after the screen has already been show.

起初 StringElements 在屏幕上看起来不错，但是如果你快速上下滚动，每行上的文本就会变成一个块:

At first the StringElements appear fine on screen, but if you scroll quickly up and down the text on each line becomes a block:

重现问题的代码:

        var root = new RootElement("Root");
        var dvc = new DialogViewController(root) { AutoHideSearch = true, EnableSearch = true };

        nav.PushViewController(dvc, true);

        Task.Factory.StartNew(() => {
                Thread.Sleep(TimeSpan.FromSeconds(1));
            UIApplication.SharedApplication.InvokeOnMainThread(() => {
                var sec = new Section();

                for (int i = 0; i < 100; i++)
                {
                    var el = new StyledStringElement("Test", "Test", UITableViewCellStyle.Value1);
                    sec.Add(el);
                }

                root.Add(sec);
            });
        });

有趣的是，只有左边的字符串看起来像一个块，而右边的则很好.附带说明一下，在他们的 MWC(演示)应用程序中，Xamarin 创建了一个新的 RootElement 来重新填充 Twitter 列表.

Interestingly only the string on the left looks like a block, while the one on the right is fine. On a side note, in their MWC (demo) app, Xamarin created a new RootElement to repopulate the twitter list as well.

推荐答案

似乎没有重新加载在主线程上调用的数据源以正确呈现新值:

There does not seem to be a reload of the data source called on the main thread to correctly render the new values:

var dvc = new DialogViewController(new RootElement(""));
_root = new UINavigationController();
_root.PushViewController(dvc, true);
_window.RootViewController = _root;

Task.Factory.StartNew(() => {
    Thread.Sleep(TimeSpan.FromSeconds(1));
    var section = new Section("");
        foreach (var i in Enumerable.Range(1, 100)) {
            section.Add(new StyledStringElement(i.ToString(), "cell", UITableViewCellStyle.Value1));
        }

    dvc.Root.Add(section);
    BeginInvokeOnMainThread(() => {
        dvc.ReloadData();
    });
});

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