迫切需要 Xamarin.IOS 像弹出窗口一样的模态 MessageBox

Question

在 Xamarin 中编码 IOS。我有一个下拉列表类型弹出窗口，如果最终用户输入新值，我想问一个 yes/no 问题：你想添加新行吗？

控件位于 UIStackView 内，而 UIStackView 位于容器 UIView 内，后者又位于另一个通过 segue 呈现的容器内。 Xamarin 需要我实现的 UIPopoverController。这是我到目前为止的代码：

using System.Threading.Tasks;
using Foundation;
using UIKit;

namespace PTPED_Engine
{

    public enum MessagePopupType
    {
        YesNo = 1,
        OKCancel = 2,
        OKOnly = 3
    }

    public enum PopupResultType
    {
        OK = 1,
        Cancel = 2,
        Yes = 3,
        No = 4
    }

    public static class AlertPopups
    {
        static NSObject nsObject;

        public static void Initialize(NSObject nsObject)
        {
            AlertPopups.nsObject = nsObject;
        }
        public static Task<PopupResultType> AskUser(UIViewController parent, UIView V, string strTitle, string strMsg, MessagePopupType mpt)
        {
            using (UIPopoverController pc = new UIPopoverController(parent))
            {
               // pc.ContentViewController
                // method to show an OK/Cancel dialog box and return true for OK, or false for cancel
                var taskCompletionSource = new TaskCompletionSource<PopupResultType>();

                var alert = UIAlertController.Create(strTitle, strMsg, UIAlertControllerStyle.ActionSheet);
                // set up button event handlers
                if (mpt == MessagePopupType.OKCancel)
                {
                    alert.AddAction(UIAlertAction.Create("OK", UIAlertActionStyle.Default, a => taskCompletionSource.SetResult(PopupResultType.OK)));
                    alert.AddAction(UIAlertAction.Create("Cancel", UIAlertActionStyle.Default, a => taskCompletionSource.SetResult(PopupResultType.Cancel)));
                }
                if (mpt == MessagePopupType.YesNo)
                {
                    alert.AddAction(UIAlertAction.Create("Yes", UIAlertActionStyle.Default, a => taskCompletionSource.SetResult(PopupResultType.Yes)));
                    alert.AddAction(UIAlertAction.Create("No", UIAlertActionStyle.Default, a => taskCompletionSource.SetResult(PopupResultType.No)));
                }
                if (mpt == MessagePopupType.OKOnly)
                {
                    alert.AddAction(UIAlertAction.Create("OK", UIAlertActionStyle.Default, a => taskCompletionSource.SetResult(PopupResultType.OK)));
                }
                // show it
                nsObject.InvokeOnMainThread(() =>
                {
                    pc.PresentFromRect(V.Bounds, V, UIPopoverArrowDirection.Any, true);
                });

                return taskCompletionSource.Task;
            }
        }
    }
}

我按如下方式调用它：

LookupCombo.Completed += async (object sender, CompletedEventArgs e) =>
{
    C1AutoComplete AC = (C1AutoComplete)sender;
    if (AC.Text.Trim() != "")
    {
        string sColName = AC.AccessibilityIdentifier.Trim();
        var ValuesVC = (List<Lookupcombo_Entry>)AC.ItemsSource;
        var IsThisAHit = from Lookupcombo_Entry in ValuesVC
                         where Lookupcombo_Entry.sDispVal.ToUpper().Trim() == e.value.ToUpper().Trim()
                         select Lookupcombo_Entry.sMapVal;
        if (!IsThisAHit.Any())
        {
            string sTitle = "";
            string sFull = _RM.GetString(sColName);
            if (sFull == null) { sFull = "???-" + sColName.Trim(); }
            sTitle = " Add New " + sFull.Trim() + "?";
            string sPPrompt = "Do you want to add a new " + sFull.Trim() + " named " + AC.Text.Trim() + " to the Database?";
            var popupResult = await AlertPopups.AskUser(CurrentViewController(), V, sTitle, sPPrompt, MessagePopupType.YesNo);
          }
    }
};

CurrentViewController 定义如下：

    private UIViewController CurrentViewController()
    {
        var window = UIApplication.SharedApplication.KeyWindow;
        var vc = window.RootViewController;
        while (vc.PresentedViewController != null)
        {
            vc = vc.PresentedViewController;
        }
        return vc;
    }

这没有任何作用。它挂起用户界面。

这应该是内置的，但它只内置在 Xamarin.Forms 中，我不想使用它。

我可以通过 await 执行此操作，但这根本行不通。有人可以帮忙吗？

谢谢！

Answer 1

这是我几年前提供的解决方案，与您优雅的方法相比，我认为这是一个丑陋的 hack。你没有说具体是哪部分不工作，这可能有助于发现问题。

这是我几年前的解决方案：

iphone UIAlertView Modal

Answer 2

您可以只使用 ACR UserDialogs 库： https://github.com/aritchie/userdialogs

迫切需要 Xamarin.IOS 像弹出窗口一样的模态 MessageBox

Desperately need Xamarin.IOS modal MessageBox like popup

xamarin.ios

uipopovercontroller

uialertcontroller