Unable to connect to localDB in VS2012 – "A network-related or instance-specific error occurred while establishing a connection to SQL Server..."

Question

This is strange as I'm able to connect to localDB through SSMS 2008R2 with the same connection string ("Data Source=(LocalDB)\v11.0;Integrated Security=true")

Only C# code is unable to connect, I have tried increasing login time with Connect Timeout=60 but no luck.

I have also tried specifying the database Initial Catalog=<databasename> where the <databasename> is the one I have created on localdb via ssms.

Any pointers as to why is this not connecting?

First connect your database through sever explorer in VS. After success of connection right click and find the property. There you will get the connection string. Just copy it and paste in the web.config. — Kundan Singh Chouhan, Sep 17 '12 at 16:18
@Kundan I did that but it threw the same error. Server explorer connected successfully, then I copied the connection string from properties as mentioned, but my app still couldn't connect using the same string. — Varun K, Sep 17 '12 at 16:34

Krzysztof Kozielczyk · Accepted Answer · 2012-09-17T19:35:28.453

47

Any chance it is because you forgot to double-escape the backslash? Did you try this:

"Data Source=(LocalDB)\\v11.0;Integrated Security=true"

Or even better, you could just use the @ mark to disable character escaping for the entire connection string:

@"Data Source=(LocalDB)\v11.0;Integrated Security=true"

edited Sep 17 '12 at 19:35

answered Sep 17 '12 at 16:42

Krzysztof Kozielczyk

5,887
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Ah, this is really the trick. Why does it require double \\? really strange .. Thanks! it worked. – Varun K Sep 17 '12 at 17:01
1

it seems \v is a special character! – Varun K Sep 17 '12 at 17:07
5

Exactly! Without the double-escape the `\v` is considered a single (and special) character. You could also use `@` (in C#) to avoid escaping whatsoever, I had updated my answer to reflect it. – Krzysztof Kozielczyk Sep 17 '12 at 19:34
1

Also, it should be noted the escape character will prevent SSMS from making the connection to LocalDb. – J. Andrew Laughlin Jun 05 '17 at 17:52
@J.AndrewLaughlin Exactly! Just use the `@` to disable escaping and make copy-pasting involve less thought :D – DrCopyPaste Jun 23 '17 at 13:58

Unable to connect to localDB in VS2012 – "A network-related or instance-specific error occurred while establishing a connection to SQL Server..."

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