xamarin.forms 如何使用 Entry 选择焦点上的所有文本？

Question

我知道 Xamarin.Android 代码，但 Xamarin.IOS 呢？

Xamarin.Android 代码:

public class CustomNumEntry : EntryRenderer
{
    public CustomNumEntry(Context context) : base(context)
    {
    }
    protected override void OnElementChanged(ElementChangedEventArgs<Entry> e)
    {
        base.OnElementChanged(e);
        if (this.Control != null)
        {
            Control.SetPadding(10, 0, 0, 15);
            Control.InputType = Android.Text.InputTypes.ClassNumber | Android.Text.InputTypes.NumberFlagSigned | Android.Text.InputTypes.NumberFlagDecimal;
            Control.TextAlignment = Android.Views.TextAlignment.Center;


        }
        if (e.OldElement == null)
        {
            var nativeEditText = (global::Android.Widget.EditText)Control;
            nativeEditText.SetSelectAllOnFocus(true);
        }

    }
}

Answer 1

对于 Xamarin iOS:

nativeTextField.EditingDidBegin += (object sender, EventArgs eIos) =>
                   {
                      nativeTextField.PerformSelector(new Selector("selectAll"), null, 0.0f);
                   };

对于 Xamarin.Forms 使用 iOS 自定义渲染器(您正在寻找):

public class CustomNumEntry : EntryRenderer
    {
        protected override void OnElementChanged(ElementChangedEventArgs<Entry> e)
        {
            base.OnElementChanged(e);    
            if (Control != null)
            {
                var nativeTextField = (UITextField)Control;    
                nativeTextField.EditingDidBegin += (object sender, EventArgs eIos) =>
                {
                   nativeTextField.PerformSelector(new ObjCRuntime.Selector("selectAll"), null, 0.0f);
                };                           
            }
        }

    }