Asp.Net与SQL Server和Asp.net Linq应用程序

Question

I have an application that uses linq-to-sql with Sql Server Express 2008. When I use the DBML file in a separate DAL project and refer to it to my web project, on execute Sql Server shows this error:

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: 26 - Error Locating Server/Instance Specified)

But when I use the DBML in my web project, debugging is without any problem. But on IIS in Windows 7 64bit i get:

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: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)

Do these two errors have the same cause? Is the connection string not correct?

Answer 1

I'd suspect that in the first case you have the connection string in the DAL project and not in your web project (where it belongs). Make sure you copy it to the web.config of your web project.

In the second case I think that that the machine hosting IIS tries to connect to the database on your own machine. If so, check the exception: make sure your SQL Express instance is configured to allow remote connections, that the IP protocol is enabled (named pipes if for local traffic), and that your machine is accessible to the IIS machine.

Answer 2

I think, Your connections string is wrong.

dont worry.

check your dbml's designer.cs file. in which you will find '<YourDBMLFile>DataContext() ' Constructor.

and Change your Connection string. make sure your connectionstring is correct.