[英]NullReferenceException on Entity Framework constructor
I have a DER.edmx
, and in DER.Designer.cs
there is this autogenerated code 我有一个DER.edmx
,在DER.Designer.cs
有这个自动生成的代码
public SiGMAEntities(string connectionString) : base(connectionString, "SiGMAEntities")
{
this.ContextOptions.LazyLoadingEnabled = true;
OnContextCreated();
}
the line that throws the exception is 引发异常的行是
public SiGMAEntities(string connectionString) : base(connectionString, "SiGMAEntities")
A couple of days ago, everything worked perfectly but I had to re-install Windows for other reasons, and of course VS and SQL Server. 几天前,一切正常,但由于其他原因,我不得不重新安装Windows,当然还有VS和SQL Server。 The exception happened when I wanted to start working on the project again. 当我想再次开始该项目时,发生了例外。
Stack trace 堆栈跟踪
[NullReferenceException: Object reference not set to an instance of an object.]
System.Collections.Generic.Dictionary`2.System.Collections.IDictionary.Remove(Object key) +48
System.Data.Metadata.Edm.MetadataWorkspace.RegisterDefaultObjectMappingItemCollection() +95
System.Data.Metadata.Edm.MetadataWorkspace.GetItemCollection(DataSpace dataSpace, Boolean required) +124
System.Data.Metadata.Edm.MetadataWorkspace.GetItemCollection(DataSpace dataSpace) +48
System.Data.Objects.ObjectContext..ctor(EntityConnection connection, Boolean isConnectionConstructor) +438
System.Data.Objects.ObjectContext..ctor(String connectionString) +65
System.Data.Objects.ObjectContext..ctor(String connectionString, String defaultContainerName) +37
AccesoADatos.SiGMAEntities..ctor(String connectionString) in E:\Documentos(NO BORRAR)\Documentos de GonDC\Facu\SiGMA\asd - Copy\trunk\AccesoADatos\DER.Designer.cs:79
AccesoADatos.Conexion.crearSegunServidor() in E:\Documentos(NO BORRAR)\Documentos de GonDC\Facu\SiGMA\asd - Copy\trunk\AccesoADatos\Conexion.cs:27
AccesoADatos.Datos.TiposDNI() in E:\Documentos(NO BORRAR)\Documentos de GonDC\Facu\SiGMA\asd - Copy\trunk\AccesoADatos\Datos.cs:14
Herramientas.CargarCombos.cargarTipoDocumento(DropDownList& ddl) in E:\Documentos(NO BORRAR)\Documentos de GonDC\Facu\SiGMA\asd - Copy\trunk\Herramientas\CargarCombos.cs:30
SiGMA._Default.Page_Load(Object sender, EventArgs e) in E:\Documentos(NO BORRAR)\Documentos de GonDC\Facu\SiGMA\asd - Copy\trunk\SiGMA\RegistrarUsuario.aspx.cs:26
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +51
System.Web.UI.Control.OnLoad(EventArgs e) +92
System.Web.UI.Control.LoadRecursive() +54
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +772
This can happen if you dont have the right connectionString specified in your App.config or web.config. 如果没有在App.config或web.config中指定正确的connectionString,则会发生这种情况。 Make sure that the running applications App.config or web.config respectively contains the connectionString that you specified when defining the database model. 确保正在运行的应用程序App.config或web.config分别包含您在定义数据库模型时指定的connectionString。 Something like this: 像这样:
<connectionStrings>
<add name="SiGMAEntities" connectionString="metadata=res://*/xxx.csdl|res://*/xxx.ssdl|res://*/xxx.msl;provider=System.Data.SqlClient;provider connection string="xxx"" providerName="System.Data.EntityClient"/>
</connectionStrings>
xxx is just a placeholder for your stuff xxx只是您的东西的占位符
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