在iOS的数字键盘上添加完成按钮没有标准的方法。在我的应用程序中，我通过在控制器导航项的右上角放置完成按钮来解决这个问题。
另一个选择是为numerical Entry创建自定义渲染器（在我们的例子中是ExtendedEntry自定义控件）。
注意：您必须更新.NET MAUI的命名空间和您的命名空间

using Xamarin.Forms;

namespace YourNamespace.Controls
{
    public class ExtendedEntry : Entry { }
}

/*
Based on example from: https://forums.xamarin.com/discussion/18346/add-done-button-to- 
   keyboard-on-ios
*/

using System.Drawing;
using YourNamespace.Controls;
using YourNamespace.iOS.Renderers;
using UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

[assembly: ExportRenderer(typeof(ExtendedEntry), typeof(ExtendedEntryRenderer))]
namespace YourNamespace.iOS.Renderers
{
    public class ExtendedEntryRenderer : EntryRenderer
    {
        protected override void OnElementChanged(ElementChangedEventArgs<Entry> e)
        {
            base.OnElementChanged(e);

            if (Element == null)
                return;

            // Check only for Numeric keyboard
            if (this.Element.Keyboard == Keyboard.Numeric)
                this.AddDoneButton();
        }

        /// <summary>
        /// <para>Add toolbar with Done button</para>
        /// </summary>
        protected void AddDoneButton()
        {
            var toolbar = new UIToolbar(new RectangleF(0.0f, 0.0f, 50.0f, 44.0f));

            var doneButton = new UIBarButtonItem(UIBarButtonSystemItem.Done, delegate
            {
                this.Control.ResignFirstResponder();
                var baseEntry = this.Element.GetType();
                ((IEntryController)Element).SendCompleted();
            });

            toolbar.Items = new UIBarButtonItem[] {
                new UIBarButtonItem (UIBarButtonSystemItem.FlexibleSpace),
                doneButton
            };
            this.Control.InputAccessoryView = toolbar;
        }
    }
}

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