为web.config写入数据库连接字符串的方法

    1.写入连接字符串

 protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            
            // Create a new ConnectionStringSettings object and populate it
            ConnectionStringSettings conn = new ConnectionStringSettings();
            conn.ConnectionString = 
                 "Server=localhost;User ID=sa;Password=123456; " + 
                 "Database=Northwind;Persist Security Info=True";
            conn.Name = "AppConnectionString2";
            conn.ProviderName = "System.Data.SqlClient";

            // Add the new connection string to the web.config
            Configuration config = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("example");
            config.ConnectionStrings.ConnectionStrings.Add(conn);
            config.Save();
        }
    }

2.修改连接字符串

protected void Page_Load(object sender, EventArgs e)
    {
        // Retrieve an existing connection string into a Connection String Builder
        System.Data.SqlClient.SqlConnectionStringBuilder builder = new
            System.Data.SqlClient.SqlConnectionStringBuilder();

        // Change the connection string properties
        builder.DataSource = "localhost";
        builder.InitialCatalog = "Northwind1";
        builder.UserID = "sa";
        builder.Password = "password";
        builder.PersistSecurityInfo = true;

        // Save the connection string back to the web.config
        Configuration config = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("/Chapter11");
        config.ConnectionStrings.ConnectionStrings["AppConnectionString1"].ConnectionString =
            builder.ConnectionString;
        config.Save();
    }