Changing SqlConnection timeout

If you want to provide a timeout for a particular query, then CommandTimeout is the way forward.

Its usage is:

command.CommandTimeout = 60; //The time in seconds to wait for the command to execute. The default is 30 seconds.

A cleaner way is to set connectionString in xml file, for example Web.Confing(WepApplication) or App.Config(StandAloneApplication).

 <connectionStrings>
    <remove name="myConn"/>
    <add name="myConn" connectionString="User ID=sa;Password=XXXXX;Initial Catalog=qualitaBorri;Data Source=PC_NAME\SQLEXPRESS;Connection Timeout=60"/>
  </connectionStrings>

By code you can get connection in this way:

public static SqlConnection getConnection()
{
        string conn = string.Empty;
        conn = System.Configuration.ConfigurationManager.ConnectionStrings["myConn"].ConnectionString;
        SqlConnection aConnection = new SqlConnection(conn);
        return aConnection;
}

You can set ConnectionTimeout only you create a instance. When instance is create you don't change this value.

You can set the timeout value in the connection string, but after you've connected it's read-only. You can read more at http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnection.connectiontimeout.aspx

As Anil implies, ConnectionTimeout may not be what you need; it controls how long the ADO driver will wait when establishing a new connection. Your usage seems to indicate a need to wait longer than normal for a particular SQL query to execute, and in that case Anil is exactly right; use CommandTimeout (which is R/W) to change the expected completion time for an individual SqlCommand.