提醒sa登录失败

提示sa登录失败
private void tree_Load(object sender, EventArgs e)
  {
  SqlConnection mysql = new SqlConnection("server = .;uid =sa; pwd = 123; database=Test");
  SqlDataAdapter myda = new SqlDataAdapter ("select * from FenChang", mysql);
  DataSet myds = new DataSet();
  myda.Fill(myds,"FenChang");
  foreach(DataRow row in myds.Tables ["FenChang"].Rows)
  {
  string filter="FCID='"+row["FCID"].ToString()+"'";
  TreeNode tn = new TreeNode();
  tn.Name = row["FCID"].ToString();
  tn.Text = row["fcName"].ToString();
  treeView1.Nodes.Add(tn);
  }
   
  }
运行到myda.Fill(myds,"FenChang");时提示登录sa失败，但数据库都正常啊

[解决办法]
SqlConnection mysql = new SqlConnection(@"server =QT-20120704NXAE\SQLEXPRESS;uid =sa; pwd = 123; database=Test");