The connection string 'MyConnection' in the application's configuration file does not contain the required providerName attribute."

问题

I use Entity Framework Code First,

My connection string is in a configuration file:

<connectionStrings>
    <clear/>
    <add name="ApplicationServices" connectionString="Data Source=PC-X;Initial Catalog=MYdb;Integrated Security=True"/>
  </connectionStrings>

When I try to access the data (something that should create the DB) is falling with the following error:

The connection string 'ApplicationServices' in the application's configuration file does not contain the required providerName attribute."

What am I missing?

回答1:

You're missing the following piece of code after the connectionString attribute (assuming that you're using SQL):

providerName="System.Data.SqlClient"

回答2:

Sometime in the future. the complete code

<add name="YouContext" connectionString="Integrated Security=True;Persist Security Info=False;Initial Catalog=YourDatabaseName;Data Source=YourPCName;" providerName="System.Data.SqlClient"/>

回答3:

Go down in your web.config until you reach the providers tag. For instance, here's my providers statement:

<providers><provider invariantName="System.Data.SqlClient" ... /></providers>

you should add this System.Data.SqlClient as a provider name in your connection string so your connection string should look like this:

  <connectionStrings>
 <add name="ApplicationServices" providerName="System.Data.SqlClient" connectionString="Data Source=PC-X;Initial Catalog=MYdb;Integrated Security=True"/>
  </connectionStrings>

回答4:

In my case the problem was with an incorrect StartUp project target. In the PM console the target migration assembly project was correct.

I have a multiproject solution and the target was on some web-service project.

So I changed the StartUp to the main WebSite project and the migration have complited without errors.

来源：https://stackoverflow.com/questions/15069403/the-connection-string-myconnection-in-the-applications-configuration-file-doe

标签

entity-framework

ef-code-first

connection-string