无法加载指定的元数据资料Unable to load the specified metadata resource

在应用ADO.NET Entity Framework构建Application时呈现如下异常。Solution 中有2个项目，一个为Windows Form项目，另一个为Class Library 项目，包含ADO.NET Entity Data Model。Windows Form 项目增长对Class Library 项目标引用。 异常信息： System.Data.MetadataException was unhandled Message="Unable to load the specified metadata resource." Source="System.Data.Entity" StackTrace: at System.Data.Metadata.Edm.MetadataArtifactLoaderCompositeResource.LoadResources（String assemblyName， String resourceName， ICollection`1 uriRegistry， MetadataArtifactAssemblyResolver resolver） at System.Data.Metadata.Edm.MetadataArtifactLoaderCompositeResource.CreateResourceLoader（String path， ExtensionCheck extensionCheck， String validExtension， ICollection`1 uriRegistry， MetadataArtifactAssemblyResolver resolver） at System.Data.Metadata.Edm.MetadataArtifactLoader.Create（String path， ExtensionCheck extensionCheck， String validExtension， ICollection`1 uriRegistry， MetadataArtifactAssemblyResolver resolver） at System.Data.EntityClient.EntityConnection.SplitPaths（String paths） at System.Data.EntityClient.EntityConnection.GetMetadataWorkspace（Boolean initializeAllCollections） at System.Data.EntityClient.EntityConnection.InitializeMetadata（DbConnection newConnection， DbConnection originalConnection， Boolean closeOriginalConnectionOnFailure） at System.Data.EntityClient.EntityConnection.Open（） 在Windows Form 项目中呈现异常的代码： [align=left] string customerID = txtCustomerID.Text.Trim（）;[/align] [align=left] // Contains a reference to an Entity Data Model （EDM） and a data source connection.[/align] [align=left] using （EntityConnection cn = new EntityConnection（"Name=NorthwindEntities"））[/align] [align=left] {[/align] [align=left] cn.Open（）;[/align] [align=left] EntityCommand cmd = cn.CreateCommand（）;[/align] [align=left] cmd.CommandText = [/align] [align=left] "SELECT VALUE c FROM NorthwindEntities.Customers "+[/align] [align=left] "AS c WHERE c.CustomerID = ＠customerID";[/align] [align=left] cmd.Parameters.AddWithValue（"customerID"， customerID）;[/align] [align=left] DbDataReader rdr = cmd.uteReader（CommandBehavior.SequentialAccess）;[/align] [align=left] while （rdr.Read（））[/align] [align=left] Console.WriteLine（rdr["CompanyName"].ToString（））;[/align] [align=left] rdr.Close（）;[/align] } 上述代码行 cn.Open（）; 抛出异常Exception - Unable to load the specified metadata resource。经搜检，题目呈如今App.config 设备文件（该设备文件在应用ADO.NET Entity Data Model领导时主动添加）， ADO.NET Entity Data Model领导主动添加的Connection String： [align=left]<configuration>[/align] [align=left]<connectionStrings>[/align] [align=left] <add name="NorthwindEntities" connectionString="metadata=res://*/NorthwindDB.csdl|res://*/NorthwindDB.ssdl|res://*/NorthwindDB.msl; provider=System.Data.SqlClient;provider connection string="Data Source=localhost;Initial Catalog=Northwind;Integrated Security=True;MultipleActiveResultSets=True""providerName="System.Data.EntityClient" />[/align] [align=left]</connectionStrings>[/align] </configuration> 须要将上方connectionStrings 设备节中的* 批改为Class Library 项目标Assembly Name。批改后的示例App.config 如下： [align=left]<configuration>[/align] [align=left]<connectionStrings>[/align] [align=left] <add name="NorthwindEntities" connectionString=" metadata= res://NorthwindEDM/NorthwindModel.csdl|res://NorthwindEDM/NorthwindModel.ssdl|res://NorthwindEDM/NorthwindModel.msl; provider=System.Data.SqlClient;provider connection string="Data Source=localhost;Initial Catalog=Northwind;Integrated Security=True;MultipleActiveResultSets=True""providerName="System.Data.EntityClient" />[/align] [align=left]</connectionStrings>[/align] </configuration The problem sometimes occurs with the Entity Framework where it gives an array of errors when doing simple operations. For example， I received an error about not being able to &＃8220;unable to load the specified metadata resource&＃8221;. Uh， the connection string information is right in the config file! The problem often can be resolved simply by: open the EDMX file in the designer mode
go to the properties of the EDMX
set the Metadata Artifact Processing property to &＃8220;Copy to Output&＃8221;
build the project
然后从输出目次将*.msl.*.ssdl，*.csdl文件拷贝到应用法度目次底下即可。呵呵（估计很多人这里失足！）