c# - 実行リーダー接続エラー

Question

    protected void Page_Load(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection("Data Source=MJ-PC;Initial Catalog=Test;Integrated Security=True ");
        con.Open();
    }

    protected void btnsubmit_Click(object sender, EventArgs e)
    {
        //SqlCommand cmd = con.CreateCommand();
        SqlCommand cmd = new SqlCommand("select password from TestDemo where userName'" + txtusername .Text+ "'", con);

        //cmd.Connection = con;

        SqlDataReader da;
        da = cmd.ExecuteReader();
        if (!da.Read())
        {
            Response.Write("Wrong Details");
        }
        else
        {
            if(da[0].ToString()==txtusername.Text)
                 Response.Redirect("WebForm1.aspx");
            else
                Response.Write("Wrong Password");
        }
    }

Answer 1

where username **=** 等号を忘れた

また、開く接続と使用する接続が異なります

Answer 2

     SqlConnection con;    
    protected void Page_Load(object sender, EventArgs e)
            {
    try
    {            
    con = new SqlConnection("Data Source=MJ-PC;Initial Catalog=Test;Integrated Security=True");
                con.Open();
    }
    catch
    {
    //Handles exceptions here
    }
            }

            protected void btnsubmit_Click(object sender, EventArgs e)
            {
              try
              {
                //SqlCommand cmd = con.CreateCommand();
                SqlCommand cmd = new SqlCommand("select password from TestDemo where userName='" + txtusername .Text+ "'", con);

                //cmd.Connection = con;

                SqlDataReader da;
                da = cmd.ExecuteReader();
                if (!da.Read())
                {
                    Response.Write("Wrong Details");
                }
                else
                {
                    if(da[0].ToString()==txtusername.Text)
                         Response.Redirect("WebForm1.aspx");
                    else
                        Response.Write("Wrong Password");
                }
              }
              finally
              {
              con.Close();
              }
            }