一个从web.cofig获取连接数据库字符的问题

Question

public partial class _Default : System.Web.UI.Page
    {
        protected SqlConnection conn;
        protected SqlDataAdapter sqlda;
        protected DataSet ds;
        protected DataTable dt;
        protected SqlCommand comm;        protected void Page_Load(object sender, EventArgs e)
        {
            conn = System.Configuration.ConfigurationManager.AppSettings["ConnectionString"].ToString();
            sqlda = new SqlDataAdapter();
            sqlda.SelectCommand = new SqlCommand("select * from lingdui",conn);
            ds = new DataSet();
            dt = new DataTable();            try
            {
                conn.Open();
                sqlda.Fill(ds, "lds");
                conn.Close();
                rpt_ld.DataSource = dt;
                rpt_ld.DataBind();
            }
            catch (Exception el)
            {
                Response.Write(el.ToString());
            }
        }
    }说conn = System.Configuration.ConfigurationManager.AppSettings["ConnectionString"].ToString();有错。无法将类型“string”隐式转换为“System.Data.SqlClient.SqlConnection”

Answer 1

ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;

Answer 2

你应该知道.
 string conn_str = System.Configuration.ConfigurationManager.AppSettings["ConnectionString"].ToString();
                conn = new SqlConnection(conn_str);

Answer 3

<connectionStrings>
<add name="ConnStr" connectionString=";database=;uid=;pwd="/>
</connectionStrings>
conn = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;

Answer 4

http://www.cnblogs.com/yedaoq/archive/2010/09/11/1824126.html

Answer 5

string conStr = System.Configuration.ConfigurationManager.AppSettings["ConnectionString"].ToString();
                conn = new SqlConnection(conStr);