Desperately need Xamarin.IOS modal MessageBox like popup

Question

Coding in Xamarin IOS. I have a drop down list type popup, where, if The end user types in a new value, I want to ask a yes/no question: Do You want to add a new row?

The control is inside a UIStackView, which is inside a container UIView, which is in turn inside another which is presented via segue. Xamarin demanded a UIPopoverController, which I implemented. Here is The code I have so far:

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;
            }
        }
    }
}

and I invoke it as follows:

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 is defined like this:

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

This does nothing. It hangs The user interface.

This should be built in, but it is only built in in Xamarin.Forms, which I do not want to use.

I have no problem in doing this stuff with an await, but this is simply not working. Can anyone help?

Thanks!

Answer 1

You can just use the ACR UserDialogs library: https://github.com/aritchie/userdialogs