我对 SqlServerCe.3.5 连接的 Entity Framework 有问题。 我有一个名为 Assets 的小项目,带有 .SDF 数据库和实体(模型名称是 Main)。 现在,当我尝试连接到实体时,发生了一些奇怪的事情。 第一次一切正常,但现在我必须添加这个:
if (edmConnection.State != ConnectionState.Open)
{
edmConnection.Open();
}
因为与实体的连接一直处于关闭状态。 添加此行后,我可以访问数据库和实体,但我收到此消息:
The specified named connection is either not found in the configuration, not intended to be used with the EntityClient provider, or not valid.
这是堆栈跟踪:
at System.Data.EntityClient.EntityConnection.ChangeConnectionString(String newConnectionString) at System.Data.EntityClient.EntityConnection..ctor(String connectionString) at System.Data.Objects.ObjectContext.CreateEntityConnection(String connectionString) at System.Data.Objects.ObjectContext..ctor(String connectionString, String defaultContainerName) at BL.Model.DBEntities..ctor() in C:\Users\Orel\Documents\Visual Studio 2010\Projects\Assets\BL\Model\Main.Designer.cs:line 34 at BL.Handlers.mModelHandler..ctor() at BL.Handlers.mModelHandler.GetOnlyInstance() in C:\Users\Orel\Documents\Visual Studio 2010\Projects\Assets\BL\Handlers\mModelHandler.cs:line 30
这是我的代码和 app.config:
private static mModelHandler _mInstance = null;
public static DBEntities m_context = null;
public static mModelHandler GetOnlyInstance()
{
if (_mInstance == null)
{
try
{
m_context = new DBEntities(GetConnectionString());
_mInstance = new mModelHandler();
}
catch (Exception)
{
throw;
}
}
return _mInstance;
}
public static EntityConnection GetConnectionString()
{
try
{
var filePath = Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
if (filePath == null) throw new ArgumentNullException("filePath");
if (filePath.EndsWith("\\Assets\\bin\\Debug"))
{
filePath = filePath.Replace("\\Assets\\bin\\Debug", "\\BL\\DB.sdf");
}
var sqlCeConnectionString = string.Format("Data Source={0}", filePath);
// Create an EDM connection
EntityConnectionStringBuilder entity = new EntityConnectionStringBuilder();
entity.Metadata = "res://*/Model.Main.csdl|res://*/Model.Main.ssdl|res://*/Model.Main.msl";
entity.Provider = "System.Data.SqlServerCe.3.5";
entity.ProviderConnectionString = sqlCeConnectionString;
var edmConnectionString = entity.ToString();
var edmConnection = new EntityConnection(edmConnectionString);
if (edmConnection.State != ConnectionState.Open)
{
edmConnection.Open();
}
return edmConnection;
}
catch (Exception e)
{
throw;
}
}
应用程序配置:
<add name="DBEntities" connectionString="metadata=res://*/Model.Main.csdl|res://*/Model.Main.ssdl|res://*/Model.Main.msl;provider=System.Data.SqlServerCe.3.5;provider connection string='Data Source=|DataDirectory|\DB.sdf'" providerName="System.Data.EntityClient" />
我在 fourm 中读到问题可能是 app.config 和连接字符串不匹配,我也试过了但它不起作用..
我刚刚添加了一张这样的图片: Link
帮助!
奥廖尔
最佳答案
我认为您的连接字符串没有被正确解析。尝试使用 "
代替 '
。
我还认为,对于 SqlCE,引号内的 provider
应该是 provider=System.Data.SqlServerCe,3.5;
而不是 provider=System .Data.SqlServerCe.3.5;
.
注意 ,
就在版本 3.5
之前。
综合起来,我们有:
<add name="DBEntities"
connectionString="metadata=res://*/Model.Main.csdl|res://*/Model.Main.ssdl|res://*/Model.Main.msl;provider=System.Data.SqlServerCe,3.5;provider connection string= "Data Source=|DataDirectory|\DB.sdf""
providerName="System.Data.EntityClient" />
希望这对您有所帮助。
关于c# - 带有 SqlServerCe.3.5 的 Entity Framework - 连接异常,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/10778134/