问Xamarin Forms iOS错误MT5202:本机链接失败

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2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): error : undef: _OBJC_CLASS_$_MLModelConfiguration
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): error : undef: _OBJC_CLASS_$_MLModel
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): error : undef: _OBJC_CLASS_$_MLDictionaryFeatureProvider
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): error : undef: _OBJC_CLASS_$_MLFeatureValue
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): error : undef: _OBJC_CLASS_$_MLMultiArray
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): error MT5211: Native linking failed, undefined Objective-C class: MLModelConfiguration. The symbol '_OBJC_CLASS_$_MLModelConfiguration' could not be found in any of the libraries or frameworks linked with your application.
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): error MT5211: Native linking failed, undefined Objective-C class: MLModel. The symbol '_OBJC_CLASS_$_MLModel' could not be found in any of the libraries or frameworks linked with your application.
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): error MT5211: Native linking failed, undefined Objective-C class: MLDictionaryFeatureProvider. The symbol '_OBJC_CLASS_$_MLDictionaryFeatureProvider' could not be found in any of the libraries or frameworks linked with your application.
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): error MT5211: Native linking failed, undefined Objective-C class: MLFeatureValue. The symbol '_OBJC_CLASS_$_MLFeatureValue' could not be found in any of the libraries or frameworks linked with your application.
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): error MT5211: Native linking failed, undefined Objective-C class: MLMultiArray. The symbol '_OBJC_CLASS_$_MLMultiArray' could not be found in any of the libraries or frameworks linked with your application.
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): warning MT5215: References to 'System' might require additional -framework=XXX or -lXXX instructions to the native linker
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): warning MT5215: References to 'System.Net.Security' might require additional -framework=XXX or -lXXX instructions to the native linker
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): warning MT5215: References to 'Kernel32' might require additional -framework=XXX or -lXXX instructions to the native linker
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): warning MT5215: References to 'libEGL' might require additional -framework=XXX or -lXXX instructions to the native linker
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): error MT5202: Native linking failed. Please review the build log.
2>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Xamarin\iOS\Xamarin.iOS.Common.targets(885,3): error : linker command failed with exit code 1 (use -v to see invocation)