با سلام و تشکر من دارم یک پروژه طراحی سایت تو ویژوال استودیو اجرا می کنم با اینکه رشنه اتصال و نمونه و migration صحیح است من چنین پیغامی در ویژوال استودیو دریافت می کنم :
An exception of type 'System.Data.SqlClient.SqlException' occurred in EntityFramework.dll but was not handled in user code
Additional information: 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: 50 - Local Database Runtime error occurred. Cannot create an automatic instance. See the Windows Application event log for error details.
An exception of type 'System.Data.SqlClient.SqlException' occurred in EntityFramework.dll but was not handled in user code
Additional information: 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: 50 - Local Database Runtime error occurred. Cannot create an automatic instance. See the Windows Application event log for error details.