No connection string named MyEntities could be found in the application config file

Question

I am using entity framework and ASP NET MVC 4 to build an application  My solution is split into two projects    A class library that includes my data model   edmx  file and a few custom interfaces The  container  MVC project that references the class library above   My problem is that when I attempt to use the  MyEntites  DbContext I get the the following error      No connection string named  MyEntities  could be found in the   application config file    I guess the problem has something to do with the fact that connection string lies within the app config of the class library rather than the MVC project   Does anyone have any suggestions

User · Answer

I had this error when attempting to use EF within an AutoCAD plugin. CAD plugins get the connection string from the acad.exe.config file. Add the connect string as mentioned above to the acad config file and it works.

Credit goes to Norman.Yuan from ADN.Network.

User · Answer

It also happens if the startup project is changed to the one  which does not have the connection strings    Right Click Solution - click properties  Under Common Properties select startup project  On the right pane select the project which has the connection strings  in most cases  it will be MVC projects - the project that starts the solution

User · Answer

As you surmise  it is to do with the connection string being in app config of the class library   Copy the entry from the class app config to the container s app config or web config file

User · Answer

The best way I just found to address this is to temporarily set that project  most likely a class library  to the startup project  This forces the package manager console to use that project as it s config source  part of the reason it is set up this way is because of the top down model that th econfig files usually follow  The rule of thumb is that the project that is closest to the client  MVC application for instance  is the web config or app config that will be used

User · Answer

Yeah  it s silly   You can avoid copying the connection string by using a connection builder   VB Net code  used in production  but slightly modified here  so treat as untested  happy to assist with any issues   where I have a serverName variable  a databaseName variable  I pass them into a method and have it generate the connection for me       Dim EfBuilder As New System Data EntityClient EntityConnectionStringBuilder  metadata res     VMware VmEf csdl res     VMware VmEf ssdl res     VMware VmEf msl provider System Data SqlClient provider connection string   data source none initial catalog none integrated security True multipleactiveresultsets True App EntityFramework        Dim SqlBuilder As New Data SqlClient SqlConnectionStringBuilder EfBuilder ProviderConnectionString                          SqlBuilder DataSource   serverName                         SqlBuilder InitialCatalog   databaseName                         EfBuilder ProviderConnectionString   SqlBuilder ConnectionString                         Using vmCtx As New VmEfConn EfBuilder ConnectionString

User · Answer

You could just pass the connection string to EntityFramework and get on with your life   public partial class UtilityContext   DbContext       static UtilityContext                 Database SetInitializer lt UtilityContext gt  null              public UtilityContext             base  Data Source SERVER Initial Catalog DATABASE Persist Security Info True User ID USERNAME Password PASSWORD MultipleActiveResultSets True                       DbSet  OnModelCreating  etc

User · Answer

I had this problem when running MSTest   I could not get it to work without the  noisolation  flag   Hopefully this helps someone   Cost me a lot of time to figure that out   Everything ran fine from the IDE   Something weird about the Entity Framework in this context

User · Answer

I got this by not having the project set as startup  as indicated by another answer   My contribution to this - when doing Add-Migrations and Update-Database  specify the startup project as part of the command in Nuget Package Manager Console  do not include the     or     characters  that s just to show you that you need to change the text located there to your project name     Enable-Migrations Add-Migrations -StartupProject  your project name that contains the data context class  Update-Database -StartupProject  same project name as above    That should do it

User · Answer

If you have multiple projects in solution  then setUp project as started where you have your truth App config

User · Answer

Add a connection string in the root web config file of  container  MVC project that references the class library as following     lt connectionStrings gt      lt add name  MyEntities  connectionString  complete connection string here  providerName  System Data SqlClient    gt      lt  connectionStrings gt    If you do not want to use  MyEntities  as connection name then change it as you wish but make the following change in your MyEntities DbContext class   MyEntities  DbContext       public MyEntities   base  Name-Of-connection-string-you wish to connect             Reason for this error is  If we will not specify the name of connection string Or connect string in derived class of DbConext In your case it is MyEntities  then DbContext will automatically search for a connection string in root web config file whoes name is same as derived class name  In your case it is My Entities

User · Answer

copy connection string to app config or web config file in the project which has set to  Set as StartUp Project  and if in the case of using entity framework in data layer project - please install entity framework nuget in main project

User · Answer

Add Connectoinstrnig in web config file   lt ConnectionStiring gt   lt add name  dbName  Connectionstring   include provider name too    gt  lt  ConnectionStiring gt

User · Answer

This problem happen when you are using Layers in your Project and defined or install Entity frame work in DataLayer and try to run your Project  So to overcome from this problem copy the connection string from the layer where the Edmx file is there and paste the connection string in main web config

User · Answer

I ve had this problem when I use multiple proyects  the start proyect with web config and app config for EntityFramework project   for avoid this problem you must    You need the connection string in the started   config file  You need have installed the EntityFramework DLL into your references

User · Answer

I have faced the same issue  I was missed to put connection string to startup project as I am performing data access operation from other layer  also if you don t have app config in your startup project then add app config file and then add a connection string to that config file

User · Answer

Regular migrations  There are two options - the first one that everyone here has suggested is to ensure that the connection string is in the Web config file of the project  When working with connection strings from Azure application settings  that means overwriting your Web config values with the Azure values   Azure or automatic migrations  programmatic   There s a second option available if you re running migrations programmatically  that allows you to run migrations using a connection string that s obtained dynamically  or via Azure application settings  without storing it in Web config   When setting the configuration s TargetDatabase  use the DbConnectionInfo constructor that takes a connection string and a provider name instead of the constructor that takes just a connection name  If your connection string doesn t have a provider name and you re using SQL Server   Azure SQL then use  System Data SqlClient

User · Answer

You are right  this happens because the class library  where the  edmx file  is not your startup   main project   You ll need to copy the connection string to the main project config file   Incase your startup   main project does not have a config file  like it was in my Console Application case  just add one  Startup project - Add New Item -  Application Configuration File    More relevant information can be found here  MetadataException  Unable to load the specified metadata resource

User · Answer

The connection string generated by the project containing the  edmx file generates the connection string  this would appear to be a holdover from the app config sorts of files that were copied to the output directory and referenced by the executable to store runtime config information   This breaks in the web project as there is no automatic process to add random  config information into the web config file for the web project   Easiest is to copy the connection string from the config file to the connections section of the web config file and disregard the config file contents

User · Answer

This could also result in not enough dll references being referenced in the calling code  A small clumsy hack could save your day   I was following the DB First approach and had created the EDMX file in the DAL Class library project  and this was having reference to the BAL Class library  which in turn was referenced by a WCF service    Since I was getting this error in the BAL  I had tried the above mentioned method to copy the config details from the App config of the DAL project  but didn t solve  Ultimately with the tip of a friend I just added a dummy EDMX file to the WCF project  with relevant DB Connectivity etc   so it imported everything necessary  and then I just deleted the EDMX file  and it just got rid of the issue with a clean build

User · Answer

Add an App Config file Set the project as startup project  Make sure you add the connection strings after entityFramework section    lt configSections gt   lt  -- For more information on Entity Framework configuration  visit http   go microsoft com fwlink  LinkID 237468 -- gt   lt section name  entityFramework  type  System Data Entity Internal ConfigFile EntityFrameworkSection  EntityFramework  Version 6 0 0 0  Culture neutral  PublicKeyToken b77a5c561934e089  requirePermission  false   gt    lt  configSections gt    lt connectionStrings gt      lt  -- your connection string goes here  after configSection -- gt   lt  connectionString gt

User · Answer

are you using more than one project on your solution   Because if you are  the web config you must check is the one on the same project as de  edmx file

User · Answer

There is a comment on the top answer by  RyanMann  that suggests      Store your connection strings in one config file  then reference them in other projects by  lt connectionString configSource     ProjectDir SharedConnections config    gt    This is a fantastic suggestion   It also works to share connection strings between App config and Web config files   Anyone wanting to follow this suggestion  should head on over to this SO answer  It has a really great step-by-step guide on sharing connection strings among multiple projects in a solution   The only caveat is that configSource must exist in the same directory or a sub-directory   The link above explains how to use  Add as Link  to get around this

User · Answer

make sure that you make your project  with the DbContext  as startup    OR  Add to the project that is set as startup your connection string in the app config  or web config   OR  Call the command like this   Update-Database -Script -ProjectName   lt project name gt   -StartupProjectName   lt project name gt   -ConnectionString  data source   initial catalog  lt db name gt  integrated security True MultipleActiveResultSets True  -ConnectionProviderName  System Data SqlClient   Then try again

User · Answer

Try copying the connections string to the  config file in the MVC project

User · Answer

It is because your context class is being inherited from DbContext  I guess your ctor is like this   public MyEntities         base  name MyEntities     name     should be changed to your connectionString s name

User · Answer

Add ConnectionString to MVC Project Web config file

User · Answer

Make sure you ve placed the connection string in the startup project s ROOT web config   I know I m kinda stating the obvious here  but it happened to me too - though I already HAD the connection string in my MVC project s Web Config  the  edmx file was placed at a different  class library project  and I couldn t figure out why I keep getting an exception    Long story short  I copied the connection string to the Views Web Config by mistake  in a strange combination of tiredness and not-scrolling-to-the-bottom-of-the-solution-explorer scenario  Yeah  these things happen to veteran developers as well

User · Answer

If you are using an MVVM model  try to copy the connection strings to all parts of your project   For example  if your solution contains two projects  the class library project and the wpf project  you must copy the connection strings of the backend project  library class porject  and place a copy in the App config file of the wpf project    lt connectionStrings gt     lt add name  DBEntities        gt   lt  connectionStrings gt    Hope it s helpful for you

[c#] No connection string named 'MyEntities' could be found in the application config file

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