Web.config and "The entry 'KEY' has already been added"

Question

My connection string of my web app (.net 2.0)  is in the web.config:

<connectionStrings>   
 <add name="KEY" connectionString="VALUE"/>
</connectionStrings>


Everything was working fine until i got this error message

System.Configuration.ConfigurationErrorsException: The entry 'KEY' has already been added. (...path...\web.config line 14)


To solve the problem, i added  a <remove name="KEY"/> before the <add/>.

My question is:
The key isn't anywhere else in the project, except in the web.config.
How can it be duplicated?

Answer 1

Could you tell us the name of the key for the collection item. Also, are you using a connection object that maps to the configuration file, on compilation time maybe it's adding the key to the list.

Answer 2

The KEY is "OGPCnString".

>>are you using a connection object that maps to the configuration file,

Didn't get the question, but this is what i'm doing:

string cn = ConfigurationManager.ConnectionStrings["OGPCnString"].ConnectionString;

new SqlConnection(cn);

The exception is thrown in  ConfigurationManager.ConnectionStrings["OGPCnString"].ConnectionString


Thanks.

Answer 3

.NET has several configuration files and they are all merged together. Your KEY is already defined in some other config file. 

Answer 4

<connectionStrings>

<remove name="KEY"/>

<add name="KEY" connectionString="Server=Manan-SQL;Database=NPSS;uid=np;pwd=np1234;connection reset=false;connection lifetime=5;enlist=true;min pool size=1;max pool size=100"/>

</connectionStrings>

 

Add 

<remove name="KEY"/>

in your web.config as above code.

This may solve your problem. . . .

 

Answer 5

Hi,

Is this happen as a result of having the connection string in two places.

I have a class library and there I gave connection string in web.config since the methods in the data layer need to access DB.
(can class libraries contail web.config? If not, is it app.config?)

I have UI in a seperate web application and I add my class library as a reference for that.

Then in the code which is getting the connection string from web.config it asks for a virtual path.

I had a virtual directory for my web application (UI) so I could give a virtual path for the web.config of that web application (not the web.config in my class library)

So, finally I came up with two connection strings in both applications.

Is that the reason for that error?

If so, what is the correct place I should save the connection string?
I mean which web.config?

I'm confused with this.

Please help!

Thanks,
Jay...

---

So Little time; So much to do!

Answer 6

Is your website in a sub folder of a multiple domain hosting account? I had a similar problem and it looks like the connection string being added in the sub-domain web.config was failing because it was already being added in the root website's web.config - probably an inheritance issue.