C# 已被抛出，Objut-C异常抛出。名称：NSInvalidArgumentException

在Xamarin中运行本机iOS应用程序时，出现以下错误

Foundation.MonoTouchException has been thrown
Objective-C exception thrown.  Name: NSInvalidArgumentException Reason: *** -[NSPlaceholderString initWithString:]: nil argument

堆栈跟踪：

**  at ObjCRuntime.Runtime.ThrowNSException (System.IntPtr ns_exception) [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/13.6.0.12/src/Xamarin.iOS/ObjCRuntime/Runtime.cs:406 
at ObjCRuntime.Runtime.throw_ns_exception (System.IntPtr exc) [0x00000] in /Users/builder/jenkins/workspace/xamarin-macios/xamarin-macios/runtime/Delegates.generated.cs:128 
at (wrapper native-to-managed) ObjCRuntime.Runtime.throw_ns_exception(intptr)
at (wrapper managed-to-native) UIKit.UIApplication.UIApplicationMain(int,string[],intptr,intptr)
at UIKit.UIApplication.Main (System.String[] args, System.IntPtr principal, System.IntPtr delegate) [0x00005] in /Library/Frameworks/Xamarin.iOS.framework/Versions/13.6.0.12/src/Xamarin.iOS/UIKit/UIApplication.cs:86 
at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x0000e] in /Library/Frameworks/Xamarin.iOS.framework/Versions/13.6.0.12/src/Xamarin.iOS/UIKit/UIApplication.cs:65 
at TripplewinEWS.iOS.Application.Main (System.String[] args) [0x00002] in /Users/yudizsolutions/Documents/projects/T/Git/TripplewinEWS/iOS/Main.cs:14 
--- End of stack trace from previous location where exception was thrown ---

at (wrapper managed-to-native) UIKit.UIApplication.UIApplicationMain(int,string[],intptr,intptr)
at UIKit.UIApplication.Main (System.String[] args, System.IntPtr principal, System.IntPtr delegate) [0x00005] in /Library/Frameworks/Xamarin.iOS.framework/Versions/13.6.0.12/src/Xamarin.iOS/UIKit/UIApplication.cs:86 
at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x0000e] in /Library/Frameworks/Xamarin.iOS.framework/Versions/13.6.0.12/src/Xamarin.iOS/UIKit/UIApplication.cs:65 
at TripplewinEWS.iOS.Application.Main (System.String[] args) [0x00002] in /Users/yudizsolutions/Documents/projects/T/Git/TripplewinEWS/iOS/Main.cs:14 **

我无法找到导致错误的真正原因。 帮我做这件事

---

提前谢谢。

您能不能显示一些代码，以及在哪一行抛出错误。它没有显示哪一行代码抛出错误。它在“Main.cs”文件UIApplication.Main（args，null，“AppDelegate”）的下一行抛出错误；你能分享你的样本项目吗，然后我可以测试它。谢谢@LeoZhu MSFT的方法。问题在于标签的文本。文本之间的空白不允许，并导致错误。为了解决此问题，我刚刚添加了\r\n我需要在标签文本中保留空白的位置。能否显示一些代码，以及引发错误的行。它没有显示引发错误的代码行。它在“Main.cs”文件UIApplication.Main（args，null，“AppDelegate”）的下一行抛出错误；你能分享你的样本项目吗，然后我可以测试它。谢谢@LeoZhu MSFT的方法。问题在于标签的文本。文本之间的空白不允许，并导致错误。为了解决此问题，我刚刚添加了\r\n需要在标签文本中保留空白的位置。