how to define a connection string using an app.config file in C#

Question

Currently i manually define my connection string in my C# code:

string ConnectionString = "Data Source=C;Initial Catalog=tickets;Integrated Security=True";
SqlConnection Conn = new SqlConnection(ConnectionString);
Conn.Open();

In my project i have an app.config file and i can see that it has a connection string. It looks like this:

<?xml version="1.0"?>
<configuration>
<configSections>
</configSections>
<connectionStrings>
    <add name="ticketNotification.Properties.Settings.ticketsConnectionString"
        connectionString="Data Source=C;Initial Catalog=tickets;Integrated Security=True"
        providerName="System.Data.SqlClient" />
</connectionStrings>
<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/></startup></configuration>

How can i define the connection string based on the app.config file in the same folder as my application?

Chandan Kumar · Answer 1 · 2014-06-27T14:38:01.663

Modify your application with this

App.config file

<?xml version="1.0"?>
  <configuration>
    <configSections>
    </configSections>
    <connectionStrings>
         <add name="ticketNotification.Properties.Settings.ticketsConnectionString"
              connectionString="Data Source=C;Initial Catalog=tickets;Integrated Security=True" providerName="System.Data.SqlClient" />
    </connectionStrings>
    <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
    </startup>
  </configuration>

and here is your code behind file. You need to use System.Configuration Namespace. System.Configuration namespace contains ConfigurationManager class which is used to get connection string from app.config/web.config files.

As this is a windows application you have App.config file where you have defined your connection string. To get that connectionstring defined in the configuration file you need to use below line of codes inside your required eventhandler

Add this namespace to your code behind (ex: Form1.cs) file

using System.Configuration;

And here inside the eventhandler add/modify these codes

  string myConnectionString = ConfigurationManager.ConnectionStrings["ticketNotification.Properties.Settings.ticketsConnectionString"].ConnectionString;

  using(SqlConnection Conn = new SqlConnection(myConnectionString))
  {
     Conn.Open();
     //Define the SQL query need to be executed as a string

    //Create your command object

    //Create Dataset,Dataadapter if required

    //add parameters to your command object - if required

   //Execute your command

   //Display success message
 }

score 7 · Accepted Answer · answered Jan 01 '14 at 18:32

7

To get connection strings from the app.config file you use the class ConfigurationManager located in the System.Configuration namespace.

To get the connection string by name and create a connection based on it, you can use the following code:

SqlConnection conn = new SqlConnection(
      ConfigurationManager.ConnectionStrings[
         "ticketNotification.Properties.Settings.ticketsConnectionString"]
             .ConnectionString);

You can read more about this here (MSDN Documentation): http://msdn.microsoft.com/en-us/library/ms254494(v=vs.110).aspx

Ensure your project holds a reference to System.Configuration, otherwise ConfigurationManager will not be available in the System.Configuration namespace.

Regards.

answered Jan 01 '14 at 18:32

João Pinho

3,725
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In .net 4.5 that doesnt exist – PriceCheaperton Jan 01 '14 at 18:34
Have you opened my link to MSDN, it's on .NET 4.5 and clearly illustrates examples using it. Are you saying that MSDN is incorrect?! – João Pinho Jan 01 '14 at 18:38
As you have helped me in the comments. I will accept your answer. – PriceCheaperton Jan 01 '14 at 18:56
Glade to help a fellow! – João Pinho Jan 01 '14 at 18:58

Andrew · Answer 3 · 2014-01-01T18:50:11.053

5

Firstly add a reference to System.Configuration by right-clicking References and selecting Add reference. Then use

Using System.Configuration

// within the class here

ConfigurationManager.ConnectionStrings["ticketNotification.Properties.Settings.ticketsConnectionString"].ConnectionString;

Obviously you will need to put in the name of your connection string in the brackets.

edited Jan 01 '14 at 18:50

answered Jan 01 '14 at 18:28

Andrew

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I am using .net 4.5 and configurationManager doesnt exist! – PriceCheaperton Jan 01 '14 at 18:31
Adding Using System.Configuration does not work – PriceCheaperton Jan 01 '14 at 18:32
According to this it does http://msdn.microsoft.com/en-us/library/system.configuration.configurationmanager%28v=vs.110%29.aspx. You need to add the reference then a Using System.Configuration call at the top. – Andrew Jan 01 '14 at 18:33
@PriceCheaperton Add reference to System.configuration assembly – Kurubaran Jan 01 '14 at 18:33
The properties you have written dont exist. Wait ill show you – PriceCheaperton Jan 01 '14 at 18:36
The connection is called "ticketsConnectionString" but how does it know to read that particular app.config file in the directory????? – PriceCheaperton Jan 01 '14 at 18:48
Use the full connection string - please see edit. – Andrew Jan 01 '14 at 18:50
@PriceCheaperton according to you the connection is called "ticketNotification.Properties.Settings.ticketsConnectionString". Also note that, app.config is a configuration file of the application, when you use ConfigurationManager it will read the configuration of the application locate in that file, it's convention. – João Pinho Jan 01 '14 at 18:50
`The name 'ConfigurationManager' does not exist in the current context ` – PriceCheaperton Jan 01 '14 at 18:52
AND i have added `using System.Configuration` – PriceCheaperton Jan 01 '14 at 18:53
@PriceCheaperton But it is working or not?! Maybe there is other problems in your project preventing it to work. – João Pinho Jan 01 '14 at 18:53
@PriceCheaperton Ok, easy, do you know how to add references to your projects? – João Pinho Jan 01 '14 at 18:53
Try right-clickuing the ConfigurationManager item and see if there is a "resolve" option. IF so, select it. – Andrew Jan 01 '14 at 18:54
I know how to add references – PriceCheaperton Jan 01 '14 at 18:54
@PriceCheaperton can you check that you have a reference called System.Configuration in your project? I'm not talking about the "using" at the top of the file. – João Pinho Jan 01 '14 at 18:55
I think i am missing a system reference from the project! – PriceCheaperton Jan 01 '14 at 18:55
@PriceCheaperton Yes, that it. One thing is add an import "using" to a reference at the top of the file. The other is add a reference to the project file itself. – João Pinho Jan 01 '14 at 18:56
Nice! It's kind of counter intuitive because you can use classes that exist inside the System.Configuration leading you to assume everything is ok, but if you do not import the System.Configuration there are some classes that are not available like System.Configuration.ConfigurationManager... – João Pinho Jan 01 '14 at 18:57

score 0 · Answer 4 · answered Jan 01 '14 at 18:46

0

You need to add a reference to System.Configuration to your project. You will then be able to add the using System.Configuration statement and get the connection string by name using:

string connectionString = ConfigurationManager.ConnectionStrings[<name>].ConnectionString;

answered Jan 01 '14 at 18:46

field_b

688
5
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The connection is called "ticketsConnectionString" is that what i put for the name? with the angled brakets? – PriceCheaperton Jan 01 '14 at 18:48
Yes. It is a string so enclose it in quotations. Remove the angled brackets. Ex: "connectionStringName" – field_b Jan 01 '14 at 19:04
Probably you have .Net 4.5 Client Profile in Project properties and that' why, you are not able to add the reference to System.configuration. If so, please change the Project Properties settings to point to .Net 4.5 ("Client" word shouldn't be there). You can go to Project Settings --> Application tab --> look for Target Framework ( it should be set to .Net Framework 4.5 – James Jan 01 '14 at 19:13
@James: I believe that got sorted already. The reference needed to be made. – field_b Jan 01 '14 at 19:20

how to define a connection string using an app.config file in C#

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