无法成功从数据库中删除记录

Question

Am I doing something wrong? Everything seems to be OK, but the record doesn't get deleted from the database:

C#

    @{
    WebSecurity.RequireAuthenticatedUser();

    myModel.OSFEntities database = new myModel.OSFEntities();

    var productInformation = Request["Pi"];

    int productId = Convert.ToInt32(productInformation.Substring(0, productInformation.LastIndexOf("-")));
    string productType = productInformation.Substring(productInformation.LastIndexOf("-", productInformation.Length)).Replace("-", String.Empty);
    var userId = WebSecurity.CurrentUserId;
    DateTime date = DateTime.Now;
    int quantity = 1;
    string quoteId = "";

    if (Request["Action"] == "Remove")
    {
        if (Session["QuoteId"] != null)
        {
            quoteId = (String)Session["QuoteId"];

            myModel.Quote quotes = database.Quotes.FirstOrDefault(
                q => q.UserId == userId && q.QuoteId == quoteId && q.ProductId == productId && q.ProductType == productType);

            database.Quotes.DeleteObject(quotes);
            database.SaveChanges();
        }
    }
}

TypeScript:

function RemoveProductFromCart(e) {
    // Remove from their Cart.
    xhr.onreadystatechange = function () {
        if (xhr.readyState == 4) {
            if (xhr.status == 200) {
                // The data is now stored in the responseText.
                // Change value in textbox to 0 so user knows it's been
                // removed from their cart.
                var el = <HTMLInputElement>document.getElementById(e.id + "-TB");
                if (el != null) {
                    el.value = "0";
                }
            }

            else {
                // Server responded with a different response code.
                alert(xhr.statusText);
            }

        }
    }

    var parameters = "Pi=" + encodeURIComponent(e.id) + "&" + "Action=Remove";

    xhr.open("POST", "../Cart.cshtml");
    xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    xhr.setRequestHeader("Content-length", parameters.length.toString());
    xhr.setRequestHeader("Connection", "close");
    xhr.send(parameters);

    return e.id;
}

While debugging with F12 Dev Tools, I see:

... which leads me to believe that it's something wrong with my C# code. Why won't it delete from the database?

Answer 1

I have a few suggestions.

In these cases it is always fairly likely that one of the request items isn't exactly what you thought it was, so either the action or the quote id could contain a surprise. You could check those using a breakpoint.

The next item to check is that myModel.Quote quotes contains the matched quote object. Perhaps one of the filters you have there is ruling it out even though the id is correct (for example it isn't linked to the current user, or the product type is different etc).

I notice you are using...

database.Quotes.DeleteObject(quotes);
database.SaveChanges();

ie you use Quotes on the first, not on the second: Should the SaveChanges and DeleteObject calls not be placed against the same context?