我正在开发Xamarin.Forms（iOS）中的一个应用程序 . 在我的日志消息频繁崩溃，如下所示：
at System.ThrowHelper.ThrowInvalidOperationException (System.ExceptionResource resource) [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.12.0.4/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/throwhelper.cs:104
at System.Collections.Generic.List 1+Enumerator[T].MoveNextRare () [0x00013] in <b238a3153e534349ad10ed0787f2157a>:0 at System.Collections.Generic.List 1 Enumerator [T] .MoveNext（）[0x0004a] in：0 at Xamarin.Forms.Picker.ResetItems（）[0x00045] in C：\ BuildAgent3 \ work \ ca3766cfc22354a1 \ Xamarin.Forms .Core \ Picker.cs：176在C：\ BuildAgent3 \ work \ ca3766cfc22354a1 \ Xamarin.Forms.Core中的Xamarin.Forms.Picker.OnItemsSourceChanged（System.Collections.IList oldValue，System.Collections.IList newValue）[0x0004c] Picker.cs：136在C：\ BuildAgent3 \ work \ ca3766cfc22354a1 \ Xamarin.Forms.Core中的Xamarin.Forms.Picker.OnItemsSourceChanged（Xamarin.Forms.BindableObject可绑定，System.Object oldValue，System.Object newValue）[0x00000] Picker.cs：120在Xamarin.Forms.BindableObject.SetValueActual（Xamarin.Forms.BindableProperty属性，Xamarin.Forms.BindableObject BindablePropertyContext上下文，System.Object值，System.Boolean CurrentlyApplying，Xamarin.Forms.Internals.SetValueFlags属性，System . 布尔静默）[0x00108]在Cam中的C：\ BuildAgent3 \ work \ ca3766cfc22354a1 \ Xamarin.Forms.Core \ BindableObject.cs：596 arin.Forms.BindableObject.SetValueCore（Xamarin.Forms.BindableProperty属性，System.Object值，Xamarin.Forms.Internals.SetValueFlags属性，Xamarin.Forms.BindableObject SetValuePrivateFlags privateAttributes）[0x0015b]在C：\ BuildAgent3 \ work \ ca3766cfc22354a1 \ Xamarin.Forms.Core \ BindableObject.cs：390在C：中的Xamarin.Forms.BindingExpression.ApplyCore（System.Object sourceObject，Xamarin.Forms.BindableObject目标，Xamarin.Forms.BindableProperty属性，System.Boolean fromTarget）[0x001f9] \ BuildAgent3 \ work \ ca3766cfc22354a1 \ Xamarin.Forms.Core \ BindingExpression.cs：174，位于C：\ BuildAgent3 \ work \ ca3766cfc22354a1 \ Xamarin.Forms.Core中的Xamarin.Forms.BindingExpression.Apply（System.Boolean fromTarget）[0x0003e] \ BindingExpression.cs：56.在Foundation.NSAsyncActionDispatcher.Apply（）的C：\ BuildAgent3 \ work \ ca3766cfc22354a1 \ Xamarin.Forms.Core \ BindingExpression.cs：551中的Xamarin.Forms.BindingExpression BindingExpressionPart.b__47_0（）[0x00000] 0x00000]在/Library/Frameworks/Xamarin.iOS中.framework / Versions / 11.12.0.4 / src / Xamarin.iOS / Foundation / NSAction.cs：125 at UIKit的UIKit.UIApplication.UIApplicationMain（int，string []，intptr，intptr）（包装托管到本机） . /Library/Frameworks/Xamarin.iOS.framework/Versions/11.12.0.4/src/Xamarin.iOS/UIKit/中的UIApplication.Main（System.String [] args，System.IntPtr principal，System.IntPtr委托）[0x00005] UIApplication.cs：79 / Uibit.UIApplication.Main（System.String [] args，System.String principalClassName，System.String delegateClassName）[0x0002c] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.12.0.4/ SRC / Xamarin.iOS / UIKit的/ UIApplication.cs：6
任何人都可以帮我解决这个问题 . 提前致谢 .