try
                {
                    //Data Source=TAOYU-PC;Database=数据库名;Integrated Security=true;
                    string Constr = "Data Source = 3MVZYGDVTI2RBLK\\SQLEXPRESS;Database=" + textBox1.Text.Trim() + ";Integrated Security=true";
                    SqlConnection conn = new SqlConnection(Constr);
                    conn.Open();
                    if (conn.State == ConnectionState.Open)
                    {
                        label1.Text = "数据库【" + textBox1.Text.Trim() + "】已经连接并打开"; 
                    }
                }
                catch
                {
                    MessageBox.Show("连接数据库失败");
                }
服务器名称没有错，为什么还是连不上数据库呢？windows 下连接