我有一个我在VS2012写的解决方案，它由4个项目组成。我在过去做过这个，在打开它们并在Xamarin中使用时，一切都运行正常，但这次我遇到了多个问题，我不知道为什么。目前，我完全被难倒，并且大部分时间都在看这个。如果有人有任何建议，我会非常感激！
我在解决方案中的所有项目中引用了两个dll文件。在Xamarin打开时，我会收到以下警告：
警告：程序集＆＃39; .............. \ vSphere-API-Builder \ Vim25Service2012.dll＆＃39;未找到。确保程序集存在于磁盘中。如果构建项目需要引用，则可能会出现编译错误。 （advantage.vmware.eventsmanager）
视觉工作室的参考文献绝对正常。因此，由于缺少引用（总共有两个），我无法构建项目，因为命名空间解析会导致错误。
消息中有趣的...... \位也显示在解决方案树中，用于引用下丢失的文件。
我尝试删除引用然后重新添加它们，但是当我选择并删除它们时，我收到以下错误：
发生了错误。保存失败。参数不能为空。参数名称：s，带有以下转储..
System.ArgumentNullException：参数不能为null。参数名称： 在System.IO.StringReader..ctor（System.String s）[0x00031]中 /private/tmp/source/bockbuild/profiles/mono-2-10/build-root/mono-2.10.12/_build/mono-2.10.12.git/mcs/class/corlib/System.IO/StringReader.cs ：53 at（wrapper remoting-invoke-with-check）System.IO.StringReader：.ctor （字符串）在Mono.Xml2.XmlTextReader..ctor（System.String xmlFragment，XmlNodeType fragType，System.Xml.XmlParserContext 上下文）[0x00000] in：0 at System.Xml.XmlTextReader..ctor（System.String xmlFragment，XmlNodeType fragType，System.Xml.XmlParserContext context）[0x00006] in /private/tmp/source/bockbuild/profiles/mono-2-10/build-root/mono-2.10.12/_build/mono-2.10.12.git/mcs/class/System.XML/System.Xml/XmlTextReader2的.cs：132 在System.Xml.XmlElement.set_InnerXml（System.String value）[0x0006f] 在 /private/tmp/source/bockbuild/profiles/mono-2-10/build-root/mono-2.10.12/_build/mono-2.10.12.git/mcs/class/System.XML/System.Xml/XmlElement的.cs：156 在MonoDevelop.Projects.Formats.MSBuild.MSBuildProperty.set_Value （System.String value）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.Formats.MSBuild/MSBuildProject.cs:437 在 MonoDevelop.Projects.Formats.MSBuild.MSBuildProjectHandler.SetIfPresentOrNotDefaultValue （MSBuildPropertySet propGroup，System.String name，System.String value，System.String defaultValue）[0x0000e] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.Formats.MSBuild/MSBuildProjectHandler.cs:1158 在MonoDevelop.Projects.Formats.MSBuild.MSBuildProjectHandler.SaveItem （IProgressMonitor监视器）[0x00c1c] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.Formats.MSBuild/MSBuildProjectHandler.cs:1115 在MonoDevelop.Projects.Formats.MSBuild.MSBuildHandler.Save （IProgressMonitor监视器）[0x0007e] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.Formats.MSBuild/MSBuildHandler.cs:128 在MonoDevelop.Projects.SolutionEntityItem.OnSave（IProgressMonitor 监视器）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/SolutionEntityItem.cs:306 在MonoDevelop.Projects.DotNetProject.OnSave（IProgressMonitor 监视器）[0x00027] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/DotNetProject.cs:726 在MonoDevelop.Projects.DefaultProjectServiceExtension.Save （IProgressMonitor监视器，MonoDevelop.Projects.SolutionEntityItem 条目）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectService.cs:647 在MonoDevelop.Projects.ProjectServiceExtension.Save（IProgressMonitor monitor，MonoDevelop.Projects.SolutionEntityItem item）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectServiceExtension.cs:67 在MonoDevelop.Projects.ProjectServiceExtension.Save（IProgressMonitor monitor，MonoDevelop.Projects.SolutionEntityItem item）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectServiceExtension.cs:67 在MonoDevelop.Autotools.MakefileProjectServiceExtension.Save （IProgressMonitor监视器，MonoDevelop.Projects.SolutionEntityItem 条目）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/addins/MonoDevelop.Autotools/MakefileProjectServiceExtension.cs:101 在MonoDevelop.Projects.ProjectServiceExtension.Save（IProgressMonitor monitor，MonoDevelop.Projects.SolutionEntityItem item）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectServiceExtension.cs:67 在MonoDevelop.Projects.ProjectServiceExtension.Save（IProgressMonitor monitor，MonoDevelop.Projects.SolutionEntityItem item）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectServiceExtension.cs:67 在MonoDevelop.Projects.ProjectServiceExtension.Save（IProgressMonitor monitor，MonoDevelop.Projects.SolutionEntityItem item）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectServiceExtension.cs:67 在MonoDevelop.Projects.ProjectServiceExtension.Save（IProgressMonitor monitor，MonoDevelop.Projects.SolutionEntityItem item）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectServiceExtension.cs:67 在MonoDevelop.Projects.ProjectServiceExtension.Save（IProgressMonitor monitor，MonoDevelop.Projects.SolutionEntityItem item）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectServiceExtension.cs:67 在MonoDevelop.Projects.CompiledAssemblyExtension.Save （IProgressMonitor监视器，MonoDevelop.Projects.SolutionEntityItem 项目）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/CompiledAssemblyProject.cs:231 在MonoDevelop.Projects.ProjectServiceExtension.Save（IProgressMonitor monitor，MonoDevelop.Projects.SolutionEntityItem item）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectServiceExtension.cs:67 在MonoDevelop.Projects.ProjectServiceExtension.Save（IProgressMonitor monitor，MonoDevelop.Projects.SolutionEntityItem item）[0x00000] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectServiceExtension.cs:67 在MonoDevelop.Projects.SolutionEntityItem.Save（IProgressMonitor 监视器）[0x0002b] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/SolutionEntityItem.cs:253 在MonoDevelop.Ide.ProjectOperations.Save （MonoDevelop.Projects.SolutionEntityItem条目）[0x0004b] in /Users/builder/data/lanes/monodevelop-lion-evolve_fixed/a8bf58d3/source/monodevelop/main/src/core/MonoDevelop.Ide/MonoDevelop.Ide/ProjectOperations.cs:362