Multiple SQL Server connection strings in app.config file

Question

I'm interested in displaying in a Windows Forms app a list of N radio buttons for the user to choose a target database server. I would like to add the SQL Server connection strings in the app.config file, so they are read by the app at runtime and rendered in the windows form as radio buttons.

At first I thought of using a delimiter to separate the connections

  <appSettings>
    <add key="ConnectionString" value="connection1|user id=user;password=123;server=10.0.0.1;database=myDatabase;connection timeout=30|connection2|user id=user;password=123;server=10.0.0.2;database=myDatabase;connection timeout=30"/>
</appSettings>

And then split the key value pairs.

Is it possible to do this in a different way?

marc_s · Accepted Answer · 2009-10-07 08:52:24Z

38

To find all defined connection strings from your app.config, use the ConfigurationManager (from System.Configuration).

It has an enumeration: ConfigurationManager.ConnectionStrings which contains all entries in your <connectionStrings>.

You can loop over it with this code:

foreach(ConnectionStringSettings css in ConfigurationManager.ConnectionStrings)
{
   string name = css.Name;
   string connString = css.ConnectionString;
   string provider = css.ProviderName;
}

The Name is just the symbolic name you give your connection string - it can be anything, really.

The ConnectionString is the connection string itself.

The ProviderName is the name of the provider for the connection, e.g. System.Data.SqlClient for SQL Server (and others for other database system). If you omit the providerName= attribute from your connection string in config, it defaults to SQL Server (System.Data.SqlClient).

Marc

answered Oct 7, 2009 at 8:52

marc_s

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1 Comment

Kiquenet Over a year ago

Gets connections strings in machine.config, not only app.config

d91-jal · Accepted Answer · 2009-10-07 08:37:51Z

18

Use the connectionStrings section to define your connection strings.

<connectionStrings>
    <add name="connection1" connectionString="user id=user;password=123;server=10.0.0.1;database=myDatabase;connection timeout=30"/>
    <add name="connection2" connectionString="user id=user;password=123;server=10.0.0.2;database=myDatabase;connection timeout=30"/>
</connectionStrings>

answered Oct 7, 2009 at 8:37

d91-jal

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2 Comments

Benjamin Ortuzar Over a year ago

how do I loop trough the childs of the "connectionStrings" element to get all the key value pairs.

d91-jal Over a year ago

foreach (ConnectionStringSettings connSettings in ConfigurationManager.ConnectionStrings) { }

Frederik Gheysels · Accepted Answer · 2009-10-07 08:36:30Z

4

Yes, it is possible to do this in another way. Check the connectionStrings section that you can make in the app.config file.

<configuration>
   <connectionStrings>
       <add name="" connectionString=""/>
        <add name="" connectionString=""/>
    </connectionStrings>
</configuration>

answered Oct 7, 2009 at 8:36

Frederik Gheysels

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Comments

Deepnath Kundu · Accepted Answer · 2015-01-18 10:48:09Z

2

We can declare multiple connection string under Web.Config or App.Config

<connectionStrings>
<add name="SourceDB" connectionString="..." />
<add name="DestinationDB" connectionString="..." />
</connectionStrings>

In DAL or .cs file you can access connection strings like this string SounceConnection = ConfigurationManager.ConnectionStrings["SourceDB"].ConnectionString; string DestinationConnection = ConfigurationManager.ConnectionStrings["DestinationDB"].ConnectionString;

answered Jan 18, 2015 at 10:48

Deepnath Kundu

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Comments

GvS · Accepted Answer · 2009-10-07 08:46:03Z

0

You can use the AppSettings class, get a list of all keys that start with ConnectionString and display them.

Your config file will look like this:

<appSettings>
  <add key="ConnectionString_Name1" value="..."/>
  <add key="ConnectionString_Name2" value="..."/>
  <add key="ConnectionString_Name3" value="..."/>
</appSettings>

You can get the name, by splitting the key name (using "_" in this example).

BTW: You should also use the ConnectionStrings section, you are only interrested in connection strings.

edited Oct 7, 2009 at 8:46

answered Oct 7, 2009 at 8:38

GvS

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1 Comment

marc_s Over a year ago

I would definitely recommend using the <connectionStrings> section in your app.config instead - that's what it's really there for!

Sergei Zinovyev · Accepted Answer · 2017-11-15 16:18:31Z

0

This is how to use LINQ to get list of connection strings:

List<string> connectionStrings = ConfigurationManager.ConnectionStrings
    .Cast<ConnectionStringSettings>()
    .Select(v => v.ConnectionString)
    .ToList();

Or you can build a dictionary of it:

Dictionary<string/*name*/, string/*connectionString*/> keyValue = ConfigurationManager.ConnectionStrings
    .Cast<ConnectionStringSettings>()
    .ToDictionary(v => v.Name, v => v.ConnectionString);

answered Nov 15, 2017 at 16:18

Sergei Zinovyev

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