سلام.باید از متد change database استفاده کنی
اینم یه مثال که توی اون از اتصال از adventureworks به master تغییر میکنه
string sqlConnectString = "Data Source=192.168.0.1,1151;" +
"Integrated security=SSPI;Initial Catalog=AdventureWorks;";
using (SqlConnection connection = new SqlConnection(sqlConnectString))
{
Console.WriteLine("ConnectionString = {0}\n",
connection.ConnectionString);
// Open the connection
connection.Open();
Console.WriteLine("=> Connection opened.\n");
Console.WriteLine("Connection.State = {0}", connection.State);
Console.WriteLine("Database = {0}\n", connection.Database);
// Change the database.
connection.ChangeDatabase("master");
Console.WriteLine("=> Database changed to ReportServer.\n");
Console.WriteLine("Connection.State = {0}", connection.State);
Console.WriteLine("Database = {0}\n", connection.Database);
// Close the connection
connection.Close();
Console.WriteLine("=> Connection closed.\n");
Console.WriteLine("Connection.State = {0}", connection.State);
Console.WriteLine("Database = {0}", connection.Database);
}
Console.WriteLine("\nPress any key to continue.");
Console.ReadKey();
منبع:کتاب اقای عبدالوهاب فخر یاسری