Question

I have a button on my asp.net webpage which I have coded to read the value of a boolean column in an access database on pageload and what the button does changes according to whether the value of the column is true or false.

Essentially this button is a show/hide button for a product (click it to hide the product, or if already hidden click it to make it visible).

I’m getting some strange behavior as when the product is hidden, clicking to make the product visible works (updates the database), however, hiding it does not and I can’t work out why one would work but the other wouldn’t.

Code is as follows:

 if (!IsPostBack)

    try
    {
        s = WebConfigurationManager.ConnectionStrings["LNDatabase"].ConnectionString;
        conn = new OleDbConnection(s);
        cmd = new OleDbCommand("SELECT * FROM products WHERE products.prod_id = @test", conn);
        OleDbParameter test = new OleDbParameter("@test", OleDbType.Integer);
        test.Value = Request.QueryString["prod_id"];
        cmd.Parameters.Add(test);

        conn.Open();
        dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
        dr.Read();
        title.Text = dr["shortdesc"].ToString();
        description.Text = dr["longdesc"].ToString();
        price.Text = dr["price"].ToString();

        productcat = dr["cat"].ToString();
        product_live = dr["live"].ToString();


    }
    catch (Exception ex)
    {
        Response.Write(ex.Message.ToString());
    }
    finally
    {
        dr.Close();
        conn.Close();
    }

protected void Page_Load(object sender, EventArgs e)

if (!IsPostBack)
    {
        bool prod_live_bool = Convert.ToBoolean(product_live);

        if (prod_live_bool == true)
        {
            live_label.Text = "This product is visible to customers";
            livelabelbutton.Text = "Hide this product";
            livelabelbutton.Click += new EventHandler(this.hideproduct_click);

        }
        else
        {
            live_label.Text = "This product is not visible to customers";
            livelabelbutton.Text = "Make this product visible";
            livelabelbutton.Click += new EventHandler(this.showproduct_click);
        }

    }

 protected void hideproduct_click(object sender, EventArgs e)
{
    string prodid = Request.QueryString["prod_id"];
    s = WebConfigurationManager.ConnectionStrings["LNDatabase"].ConnectionString;
    string str = "UPDATE products SET live = @hide WHERE prod_id=@product";

    using (OleDbConnection conn = new OleDbConnection(s))
    {
        using (OleDbCommand cmd = new OleDbCommand(str, conn))
        {
            OleDbCommand mycommand = new OleDbCommand();

            OleDbParameter hideparam = new OleDbParameter("@hide", OleDbType.Boolean);
            hideparam.Value = false;
            cmd.Parameters.Add(hideparam);
            OleDbParameter product = new OleDbParameter("@product", OleDbType.VarChar);
            product.Value = prodid;
            cmd.Parameters.Add(product);

            conn.Open();
            cmd.ExecuteNonQuery();
        }
    }
    Response.Redirect(Request.RawUrl);
}

protected void showproduct_click(object sender, EventArgs e)
{
    string prodid = Request.QueryString["prod_id"];

    s = WebConfigurationManager.ConnectionStrings["LNDatabase"].ConnectionString;
    string str = "UPDATE products SET live = @show WHERE prod_id=@product";

    using (OleDbConnection conn = new OleDbConnection(s))
    {
        using (OleDbCommand cmd = new OleDbCommand(str, conn))
        {
            OleDbCommand mycommand = new OleDbCommand();

            OleDbParameter hideparam = new OleDbParameter("@show", OleDbType.Boolean);
            hideparam.Value = true;
            cmd.Parameters.Add(hideparam);
            OleDbParameter product = new OleDbParameter("@product", OleDbType.VarChar);
            product.Value = prodid;
            cmd.Parameters.Add(product);

            conn.Open();
            cmd.ExecuteNonQuery();
        }
    }
    Response.Redirect(Request.RawUrl);
}

Sorry for the long code.

Answer 1

If the point of the command button is to toggle the value of the [live] Yes/No field, let the db engine do what you need.

UPDATE products SET live = (Not live) WHERE prod_id=@product

Not returns the inverse of a Boolean value. So Not True returns False and Not False returns True. Therefore the UPDATE statement sets live to the inverse of whatever it contained before executing the UPDATE. Try it in an Access session as a new query to examine how it operates.

If that is satisfactory, you wouldn’t need separate routines for hide and show.