How to select the connnection string during runtime?

Question

Hello,

How to select the connection string from multiple instances in web config file using web api controller?

 

<connectionStrings>

<add name="client_db1" connectionString="Data Source=DESKTOP;Initial Catalog=Client1;User ID=sa;Password=****;" />

<add name="client_db2" connectionString="Data Source=DESKTOP;Initial Catalog=Client2;User ID=sa;Password=****;" />

<add name="client_db3" connectionString="Data Source=DESKTOP;Initial Catalog=Client3;User ID=sa;Password=****;" />

</connectionStrings>

 

Please help 

Thanks