How to write connection string in web config file and read from it

Question

I m trying to write Connection string to Web config like this    lt connectionStrings gt     lt add name  Dbconnection  connectionString  Server localhost          Database OnlineShopping   Integrated Security True   gt   lt  connectionStrings  gt    and read from it like this   string strcon        ConfigurationManager ConnectionStrings  Dbconnection   ConnectionString  SqlConnection DbConnection   new SqlConnection strcon     when run the program I get an error because of the null reference  but when I use this code   SqlConnection DbConnection   new SqlConnection    DbConnection ConnectionString         Server localhost  Database OnlineShopping   Integrated Security True     I don t get any error and the program works correctly  What is the problem

User · Answer

Try to use WebConfigurationManager instead of ConfigurationManager

User · Answer

Web config    lt connectionStrings gt       lt add name  ConnStringDb  connectionString  Data Source localhost           Initial Catalog DatabaseName  Integrated Security True             providerName  System Data SqlClient    gt   lt  connectionStrings gt    c  code   using System Configuration  using System Data  SqlConnection  connection   new SqlConnection            ConfigurationManager ConnectionStrings  ConnStringDb   ToString      try       if  connection State  ConnectionState Closed           connection Open      catch

User · Answer

Add reference to add System Configuration -  System Configuration ConfigurationManager      ConnectionStrings  connectionStringName   ConnectionString    Also you can change the WebConfig file to include the provider name -   lt connectionStrings gt     lt add name  Dbconnection          connectionString  Server localhost  Database OnlineShopping         Integrated Security True   providerName  System Data SqlClient    gt   lt  connectionStrings gt

User · Answer

After opening the web config file in application  add sample db connection in connectionStrings section like this    lt connectionStrings gt         lt add name  yourconnectinstringName  connectionString  Data Source  DatabaseServerName  Integrated Security true Initial Catalog  YourDatabaseName  uid YourUserName  Password yourpassword    providerName  System Data SqlClient    gt      lt  connectionStrings gt      Declaring connectionStrings in web config file     lt add name  dbconnection  connectionString  Data Source Soumalya Integrated Security true Initial Catalog MySampleDB  providerName  System Data SqlClient    gt       There is no need of username and password to access the database server  Now  write the code to get the connection string from web config file in our codebehind file  Add the following namespace in codebehind file   using System Configuration    This namespace is used to get configuration section details from web config file   using System    using System Data SqlClient    using System Configuration    public partial class  Default  System Web UI Page         protected void Page Load object sender  EventArgs e                Get connection string from web config file           string strcon   ConfigurationManager ConnectionStrings  dbconnection   ConnectionString              create new sqlconnection and connection to database by using connection string from web config file           SqlConnection con   new SqlConnection strcon             con Open

User · Answer

try this  var configuration   WebConfigurationManager OpenWebConfiguration       var section    ConnectionStringsSection configuration GetSection  connectionStrings    section ConnectionStrings  MyConnectionString   ConnectionString    Data Source       configuration Save

User · Answer

Try this After open web config file in application and add sample db connection in connectionStrings section like this    lt connectionStrings gt   lt add name  yourconnectinstringName  connectionString  Data Source  DatabaseServerName  Integrated Security true Initial Catalog  YourDatabaseName  uid YourUserName  Password yourpassword    providerName  System Data SqlClient   gt   lt  connectionStrings  gt

User · Answer

Are you sure that your configuration file  web config  is at the right place and the connection string is really in the  generated  file  If you publish your file  the content of web release config might be copied   The configuration and the access to the Connection string looks all right to me  I would always add a providername   lt connectionStrings gt     lt add name  Dbconnection          connectionString  Server localhost  Database OnlineShopping          Integrated Security True  providerName  System Data SqlClient    gt   lt  connectionStrings gt

[c#] How to write connection string in web.config file and read from it?

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