Entity framework throwing invalid operation exception - Connection string in app.config not found

c# entity-framework entity-framework-6


I added a new ADO.NET data model from the database, and everything generated fine.

Then I try to make a call to get one of the tables:

public Sensor[] GetAllRegisteredSensors()
            using (var context = new ClientSensorLocationEntities())
                    return context.Sensors.ToArray();

                catch (Exception ex)

and I get an exception:

No connection string named 'ClientSensorLocationEntities' could be found in the application config file.

Pretty self-explanatory and then I went to my app.config file which looks like this:

<?xml version="1.0" encoding="utf-8"?>
    <add name="ClientSensorLocationEntities" connectionString="metadata=res://*/ClientSensorLocationModel.csdl|res://*/ClientSensorLocationModel.ssdl|res://*/ClientSensorLocationModel.msl;
               provider=System.Data.SqlClient;provider connection string=&quot;data source=MYUSER\SQLEXPRESS;initial catalog=ClientSensorLocation;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework&quot;"
               providerName="System.Data.EntityClient" />
                <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6" />

So the connection string with that name exists. What seems to be the problem then?

11/2/2015 8:46:52 AM

Accepted Answer

If you are using DbContext from referencing Projects, you also need to register the connection string on the project configuration file.

For example, if you are using the DbContext on a web project, check if the connection string is on the web.config.

8/13/2016 1:59:03 AM

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