尝试为文件D：\ Stra.mdf附加自动命名的数据库失败

Question

我们正在我们学院创建一个项目。执行时我们收到此错误。我们有注册页面，我们点击注册并获得this错误

Answer 1

 private void button1_Click(object sender, EventArgs e)
        {
           string Constring = ConnectionString.Constring;
           SqlConnection con = new SqlConnection(Constring);
            con.Open();
            SqlCommand cmd = new SqlCommand("select usname,pwd from regis where usname='" + textBox1.Text + "'", con);
            SqlDataReader dr;
            dr = cmd.ExecuteReader();
            while (dr.Read())
            {
                 usname = dr["usname"].ToString();
                 pwd = dr["pwd"].ToString();
            }
                        dr.Close();
            con.Close();
            if (textBox1.Text == usname && textBox2.Text == pwd)
            {
                this.Hide();
                UserHome us = new UserHome(textBox1.Text);
                us.Show();
            }
            else
            {
                MessageBox.Show("Invalid USername or Password");
            }

        }