نمی توانم با استفاده از روش codefirst به sql server متصل بشم

Unhandled Exception: System.Data.SqlClient.SqlException: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 52 – Unable to locate a Local Database Runtime installation. Verify that SQL Server Express is properly installed and that the Local Database Runtime feature is enabled.) —> System.ComponentModel.Win32Exception: The system cannot find the file specified
— End of inner exception stack trace —
at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)
at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)
at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource1 retry, DbConnectionOptions userOptions)
at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource1 retry, DbConnectionOptions userOptions)
at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource1 retry)
at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource1 retry)
at System.Data.SqlClient.SqlConnection.Open()
at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.<>c.<Open>b__13_0(DbConnection t, DbConnectionInterceptionContext c)
at System.Data.Entity.Infrastructure.Interception.InternalDispatcher1.Dispatch[TTarget,TInterceptionContext](TTarget target, Action2 operation, TInterceptionContext interceptionContext, Action3 executing, Action3 executed)
at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Open(DbConnection connection, DbInterceptionContext interceptionContext)
at System.Data.Entity.SqlServer.SqlProviderServices.<>c__DisplayClass60_0.<UsingConnection>b__0()
at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.<>c__DisplayClass2_0.<Execute>b__0()
at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func1 operation)
at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Action operation)
at System.Data.Entity.SqlServer.SqlProviderServices.UsingConnection(DbConnection sqlConnection, Action1 act)
at System.Data.Entity.SqlServer.SqlProviderServices.UsingMasterConnection(DbConnection sqlConnection, Action1 act)
at System.Data.Entity.SqlServer.SqlProviderServices.CreateDatabaseFromScript(Nullable1 commandTimeout, DbConnection sqlConnection, String createDatabaseScript)
at System.Data.Entity.SqlServer.SqlProviderServices.DbCreateDatabase(DbConnection connection, Nullable1 commandTimeout, StoreItemCollection storeItemCollection)
at System.Data.Entity.Core.Common.DbProviderServices.CreateDatabase(DbConnection connection, Nullable1 commandTimeout, StoreItemCollection storeItemCollection)
at System.Data.Entity.Core.Objects.ObjectContext.CreateDatabase()
at System.Data.Entity.Migrations.Utilities.DatabaseCreator.Create(DbConnection connection)
at System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists(Action mustSucceedToKeepDatabase)
at System.Data.Entity.Migrations.DbMigrator.Update(String targetMigration)
at System.Data.Entity.Internal.DatabaseCreator.CreateDatabase(InternalContext internalContext, Func`3 createMigrator, ObjectContext objectContext)
at System.Data.Entity.Internal.InternalContext.CreateDatabase(ObjectContext objectContext, DatabaseExistenceState existenceState)
at System.Data.Entity.Database.CreateIfNotExists()
at CodeFirst_Test.Program.Main(String[] args) in C:UsersASUSDesktopC# testCodeFirst_TestProgram.cs:line 16