No connection string named 'SMSEntities' could be found .

Hi frnds...

 

i have configured a wpf application and make BAL and DAl and WpfApp three project in my solutions . I have Added Entity Framework in DAL and class file in BAl. when i am going to run the application it shows the error "No connection string named 'SMSEntities' could be found in the application config file."

there is a app.config file in my DAL.

 

When i get this error then i have added an app.config file in  WpfApp project also, And add the connection string in that file. But still i am getting the same error when i am going to insert the record in database 

 

DAL(App.config content)