How to declare a variable in app.config file?

Question

I am working on a windows application. I have a form with labels like

HOST:
UserName:
Password:

How can I declare a connection string in a file app.configso that as variables that I can use in the future, for the initial directory, user ID and password, I can check whether which database the user was connected to, enter the user ID and password.

I am using SQL Server 2008 and Visual C # 2008 Express Edition.

Answer 1

The app.configsection is located <connectionString>.

<connectionStrings>
    <add name="MyDatabase" connectionString="Data Source=sqlserver,1433;Network Library=DBMSSOCN;Initial Catalog=MyDatabase;User ID=xxx;Password=xxxx;" />
  </connectionStrings>

, <appSettings>.

Answer 2

, , . :

<add name="myDBKey" connectionString="Data Source=myDB;Initial Catalog={0};Persist Security Info=True;User ID={1};Password={2}" providerName="System.Data.SqlClient"/>

, String.Format .

string dbCatalog = "myCatalog";
string dbUser = "myUser";
string dbPW = "myPW";

string myDBConnectionString = String.Format(
    ConfigurationManager.ConnectionStrings["myDBKey"].ConnectionString,
    dbCatalog, dbUser, dbPW);

.

Answer 3

- ,

<appSettings>
    <add key="SettingName" value="SettingValue" />
</appSettings>

" app.config/web.config.

Answer 4

<connectionStrings>
    <add name="ConString" connectionString="Server=Servernae;Database=DBName;User Id=username;password=yourpassword"/>
    </connectionStrings>

Answer 5

, , "" (), , , ( Application).

, :

using System.Configuration;
//....
ConfigurationSettings.AppSettings["ConnectionString"].ToString();
// or
ConfigurationSettings.AppSettings.ConnectionString;

, .

EDIT:

connectionStrings node, ( app.config. . MSDN .

XML:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <connectionStrings>
    <add name="ConnStr1" connectionString="LocalSqlServer: data source=127.0.0.1 Integrated Security=SSPI;Initial Catalog=aspnetdb"
      providerName="System.Data.SqlClient" />
  </connectionStrings>
</configuration>

# System.Coonfiguration.ConnectionStrings, ConnectionStringSettings.

C # code usage example: http://msdn.microsoft.com/en-us/library/system.configuration.configurationmanager.connectionstrings.aspx