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();
}