SqlConnection in C#

Question

In VB.NET I can use:

Protected Conn As New SqlConnection(ConfigurationManager.ConnectionStrings("Active").ConnectionString)

However, when I do the following in C#:

protected SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings("conn"));

I get the error:

The name 'ConfigurationManager' does not exist in the current context

Then if I change it to:

protected SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings("conn"));

I get the error:

Non-invocable member 'System.Configuration.ConfigurationManager.ConnectionStrings' cannot be used like a method.

Why is this and how can I connect to my SQL Server database using C#?

Darin Dimitrov · Accepted Answer · 2011-08-21 16:15:47Z

11

Try like this:

protected SqlConnection conn = new SqlConnection(
    ConfigurationManager.ConnectionStrings["conn"].ConnectionString
);

Notice the [] instead of () which is what is used to access an element of an array in C#. Also notice the usage of the .ConnectionString property call as the SqlConnection constructor expects a string.

answered Aug 21, 2011 at 16:15

Darin Dimitrov

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4 Comments

Curtis Over a year ago

I'm still getting The name 'ConfigurationManager' does not exist in the current context. But I've added System.Configuration to my References

TrueWill Over a year ago

@Curt - try adding "using System.Configuration;" at the top. And remember to also use the using statement as Ofer Zelig suggests.

Darin Dimitrov Over a year ago

@Curt, make sure you have referenced the System.Configuration assembly to your project and that you have added a using System.Configuration in order to bring the ConfigurationManager class insto scope.

Curtis Over a year ago

I definetely have referenced it and I've used using System.Configuration too... very confused

Ofer Zelig · Accepted Answer · 2011-08-21 16:16:41Z

8

Change the last pair of parentheses to square brackets. In C#, parentheses are used in method calls, whether square brackets are used to access members inside a collection (or so).

In addition, use the using clause to ensure that the connection is always closed and disposed when you go out of scope:

using (SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["conn"]))
{
...
}

Read about it here: http://msdn.microsoft.com/en-us/library/yh598w02(v=vs.80).aspx

answered Aug 21, 2011 at 16:16

Ofer Zelig

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Comments

Neil Fenwick · Accepted Answer · 2011-08-21 16:18:54Z

2

In C#, you read collections using square bracket syntax:

e.g.

string[] strings = new[] { "first", "second", "third" };

string secondString = strings[1];

So you access the Configuration collection like this:

ConfigurationManager.ConnectionStrings["conn"];

answered Aug 21, 2011 at 16:18

Neil Fenwick

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