Develop Reference

c# connection string and concatenation app.config

I have the following connection string through which i connect to an Access database(.mdb) located in a sub-folder inside the root-folder of my application :
OleDbConnection con = new OledbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + System.AppDomain.CurrentDomain.BaseDirectory() + "Data\rctts.mdb;Jet OLEDB:Database Password=mypassword;")
My question is, how do i put the connection string in the app.config file? Generally, i use :
<connectionStrings>
<add name="Test" connectionString="Data Source=.;Initial Catalog=OmidPayamak;Integrated Security=True" providerName="System.Data.SqlClient" />
</connectionStrings>
The issue i am facing is that in my connection string, i am doing some concatenations and also using System.AppDomain.CurrentDomain.BaseDirectory() to set the Data Source...
How do i do the same concatenation in app.config ? Is it possible to do so ?

You could try the following:
connectionString="Data Source=|DataDirectory|\rctts.mdb;Initial Catalog=OmidPayamak;Integrated Security=True"
and then try to set the value of DataDirectory as below:
var currentDomain = AppDomain.CurrentDomain;
var basePath = currentDomain.BaseDirectory;
currentDomain.SetData("DataDirectory", basePath+"\Data");
at the corresponding startup file of your application.

Although configuration APIs offer no facilities to manipulate connection strings for you, you could place connection string "template" into configuration, and do the rest of manipulation in your code using string.Format:
Config:
<connectionStrings>
<add name="Test" connectionString="Data Source={0}Data\rctts.mdb;Initial Catalog=OmidPayamak;Integrated Security=True" providerName="System.Data.SqlClient" />
</connectionStrings>
C# code:
string conStr = string.Format(
ConfigurationManager.ConnectionStrings["Test"].ConnectionString
, System.AppDomain.CurrentDomain.BaseDirectory()
);

Entity Framework unable to find connection string in nested web.config

I'm new to .NET, but I'm using EntityFramework 5.0 and .NET 4.5
I have a website where the connectionStrings in the web.config are maintained in a configSource as follows:
<connectionStrings configSource="ConfigOverrides\overrideConnectionStrings.config">
</connectionStrings>
My website has modules with nested web.config files. These modules specify their own connectionStrings in the nested web.config. Everything was fine until I put a System.Data.EntityClient connection in my ConfigOverrides\overrideConnectionStrings file. After I did this I would get an error from the module:
No connection string named 'WebsiteEntities' could be found in the application config file.
If I copy the module's connectionString to the one in ConfigOverrides I get an error that there is already a connection string with that name. If I remove the connection string from their nested web.config and just put it in my overrides, it works. However I'm not wanting to maintain all module's connectionSettings in that global override.
Contents of overrideConnectionStrings.config:
<connectionStrings>
<add name="SqlServices" connectionString="Data Source=(LocalDb)\v11.0;Initial Catalog=my_db;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\my_db.mdf;" />
<add name="TermsEntities" providerName="System.Data.EntityClient" connectionString="metadata=res://*/Terms.csdl|res://*/Terms.ssdl|res://*/Terms.msl;provider=System.Data.SqlClient;provider connection string='data source=(LocalDb)\v11.0;Initial Catalog=my_db;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\my_db.mdf;connect timeout=30;MultipleActiveResultSets=True;App=EntityFramework'" />
<add name="ADServer" connectionString="LDAP://ldap.localdomain:389/DC=company,DC=com" />
</connectionStrings>
Contents of module's nested Web.config connectionStrings:
<connectionStrings>
<add name="WebsiteEntities" connectionString="metadata=res://*/WSE.csdl|res://*/WSE.ssdl|res://*/WSE.msl;provider=System.Data.SqlClient;provider connection string="data source=.;initial catalog=WSE_DB;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework"" providerName="System.Data.EntityClient" />
<add name="RoutingConn" providerName="System.Data.SqlClient" connectionString="data source=.;initial catalog=WSE_DB;integrated security=True;" />
</connectionStrings>
I should note that the module worked fine until I added my TermsEntities to the main site's web.config (via the ConfigOverrides).

I am still unable to figure out what in my application setup is causing the connectionString to not be found. While debugging I could view the connectionStrings available to the path of the request and I would see all connectionStrings (those in the nested web.config and those in the root web.config).
My workaround is to just use the ConfigurationManager from System.Configuration and read in the connection string :
public partial class WebsiteEntities : DbContext
{
public WebsiteEntities()
: base(ConfigurationManager.ConnectionStrings["WebsiteEntities"].ConnectionString ?? "name=WebsiteEntities")
{
}
...
This seems to be working.

Store connection string in database and retrieve it on application startup

I am developing an winforms application in VS 2010 to retrive data from Sql Server or MySql to Sql Server or MySql.
My design is something like this.
So here I am storing all values of connection string in Sql Server database table in separate column.
I am able to get the required fields and validate them, test them and store it in database but I am stuck at how to get the stored connection string at runtime to work and how to use the last selected connection string?
guidance please.

Your config file might have a connectionStrings section like this:
<connectionStrings>
<add name="ConnectionNumberOne"
connectionString="Data Source=ds;Initial Catalog=DB;Integrated Security=True"
providerName="System.Data.SqlClient" />
<add name="ConnectionNumberTwo"
connectionString="Data Source=ds2;Initial Catalog=DB2;Integrated Security=True"
providerName="System.Data.SqlClient" />
</connectionStrings>
You can read the connection string thusly:
var connectionOne = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionNumberOne"];
var connectionTwo = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionNumberTwo"];
And you can save the connection string as well:
Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
config.ConnectionStrings.ConnectionStrings["ConnectionNumberOne"].ConnectionString = //CONCATINATE YOUR FIELDS TOGETHER HERE
config.Save(ConfigurationSaveMode.Modified, true);
ConfigurationManager.RefreshSection("connectionStrings");

c# Loading connectionString from file on runtime

I have an application (Console) already in place which is reading connection string from the bin directory.
We are planning to pass a directory path from command line which would point to the configurations.This way we would be able to switch between pointing to different DBs by just changing the command line parameter for "ConfigurationDirectory"
This requires us to dynamically load the connectionstring, the format of my connection string is as below :
<connectionStrings>
<add name="DB1" connectionString="Data Source=DB;Initial Catalog=someCatalog;Persist Security Info=True;User ID=****;Password=****; Asynchronous Processing=true" providerName="System.Data.SqlClient" />
<add name="DB2" connectionString="Data Source=DBName;Initial Catalog=someCatalog2;Persist Security Info=True;User ID=****;Password=****; Asynchronous Processing=true" providerName="System.Data.SqlClient" />
</connectionStrings>
We do not have a configuration tag.
To load up the connection string dynamically I am trying this :
var connectionStringconfigfile = "C:Somepath\connectionstring.config"
ExeConfigurationFileMap configMap = new ExeConfigurationFileMap();
configMap.ExeConfigFilename = connectionStringconfigfile;
Configuration config = ConfigurationManager.OpenMappedExeConfiguration(configMap, ConfigurationUserLevel.None);
config.Save(ConfigurationSaveMode.Modified);
ConfigurationManager.RefreshSection("connectionStrings");
I am unable to use the connectionstring file I have currently because it complains that there is no configuration tag.
The problem is that my code already uses the following to initialize connection string :
ConfigurationManager.ConnectionStrings["DB1"].ConnectionString
With this new approach the above line does not seem to work and always gives me null, is there a way so that I do not have to change my existing code?

If you wrap your external config file in a <configuration> block, like this:
<configuration><br>
<connectionStrings><br>
<add name="DB1" connectionString="Data Source=DB;Initial Catalog=someCatalog;Persist Security Info=True;User ID=****;Password=****; Asynchronous Processing=true" providerName="System.Data.SqlClient" /><br>
<add name="DB2" connectionString="Data Source=DBName;Initial Catalog=someCatalog2;Persist Security Info=True;User ID=****;Password=****; Asynchronous Processing=true" providerName="System.Data.SqlClient" /><br>
</connectionStrings><br>
</configuration>
Your code should work.

C# Sql Connection String Across Pages

If I have several pages what would be the correct procedure in creating a connection string variable and sharing it among all of my pages. I would prefer not to type the connection string 100 times for each page and would just rather call it. Can I create it in my namespace or whats the best approach?

Put the connection string in the web.config file. See the following on MSDN: How to: Read Connection Strings from the Web.config File
Example of connection string in config:
<connectionStrings>
<add name="Movies2"
connectionString="Data Source=(local);Initial Catalog=Movies;User ID=wt3movies;Password=lalalalala;Integrated Security=SSPI"
providerName="System.Data.SqlClient" />
</connectionStrings>
Using the string:
string connStr = ConfigurationManager.ConnectionStrings["Movies2"].ConnectionString;

It's typically in your configuration file (web.config)

can't you use the <connectionStrings/> configuration ?
http://msdn.microsoft.com/en-us/library/ms178411.aspx

Well i would have included Setting file and placed it over there.It may be not the best bet but works for me.

There are many options. It depends on what data access methodology you are using. I would suggest creating a class to handle loading the connection string from the web.config file and exposing it as a public property.

There are a variety of ways to approach this which would delve in to architecture/SOC/IoC/Repository/ etc, but to answer your question in its simplest possible sense, you could create a Database class that had a single method that fetched your connection string from configuration.
internal class DataAccess
{
static string GetDatabaseConnection()
{
return ConfigurationManager.ConnectionStrings["AppDb"].ConnectionString;
// where AppDb is defined in your web.config/app.config.
}
}
Your pages could just use:
string connection = DataAccess.GetDatabaseConnection();

connection strings are usually stored in configuration files such as the web config. Here is a simple example
add something like this to the config
<connectionStrings>
<add
name="NorthwindConnectionString"
connectionString="Data Source=serverName;Initial
Catalog=Northwind;Persist Security Info=True;User
ID=userName;Password=password"
providerName="System.Data.SqlClient"
/>
</connectionStrings>
and then retrive it as
System.Configuration.Configuration rootWebConfig =
S
ystem.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("/MyWebSiteRoot");
System.Configuration.ConnectionStringSettings connString;
if (rootWebConfig.ConnectionStrings.ConnectionStrings.Count > 0)
{
connString =
rootWebConfig.ConnectionStrings.ConnectionStrings["NorthwindConnectionString"];
if (connString != null)
Console.WriteLine("Northwind connection string = \"{0}\"",
connString.ConnectionString);
else
Console.WriteLine("No Northwind connection string");
}
full article is here http://msdn.microsoft.com/en-us/library/ms178411.aspx

You should keep it in you config file. For winforms that will be app.config, and for webforms it's web.config. Here is the section you need to have (for winforms).
<connectionStrings>
<add name="MyNameSpace.Properties.Settings.ConnectionString1"
connectionString="Data Source=MYSQLSERVER;Initial Catalog=DATABASENAME;Integrated Security=True"
providerName="System.Data.SqlClient" />
</connectionStrings>
Then you can access the connection string like this (depending on your .NET version - this is for 2.0)
string connectionString = ((string)(configurationAppSettings.GetValue(ConnectionString1"", typeof(string))));

Have the connection string (CS) in (App/Web).Config file and have the CS returned from a static method GetConncectionString().It means, this particular static method would be used in all the pages where CS is required.

You can also make a file called connectionStrings.config,or a name you choose, with this content:
<connectionStrings>
<add name="MyConnection" connectionString="server=MyServer; database=MyDataBase; user id=myUser; pwd=MyPwd;"/>
</connectionStrings>
And then, in your Web.Config
Insert this tag under node
<connectionStrings configSource="connectionStrings.config"/>