Question

我刚刚开始使用asp .NET MVC 2应用程序，我偶然发现了一个问题。我在更新表格时遇到问题。调试器不报告任何错误，它只是没有做任何事情......我希望有些人可以帮助我。感谢您的时间。这是我的控制器代码......

public ActionResult Edit(int id)
    {
        var supplierToEdit = (from c in _entities.SupplierSet
                              where c.SupplierId == id
                              select c).FirstOrDefault();

        return View(supplierToEdit);
    }

    //
    // POST: /Supplier/Edit/5

    [AcceptVerbs(HttpVerbs.Post)]
    public ActionResult Edit(Supplier supplierToEdit)
    {
        if (!ModelState.IsValid)
            return View();

        try
        {
            var originalSupplier = (from c in _entities.SupplierSet
                                    where c.SupplierId == supplierToEdit.SupplierId
                                    select c).FirstOrDefault();

            _entities.ApplyPropertyChanges(originalSupplier.EntityKey.EntitySetName, supplierToEdit);
            _entities.SaveChanges();
            // TODO: Add update logic here

            return RedirectToAction("Index");
        }
        catch
        {
            return View();
        }
    }

这是我的观点...

<h2>Edit</h2>

<% using (Html.BeginForm()) {%>
    <%= Html.ValidationSummary(true) %>

    <fieldset>
        <legend>Fields</legend>



        <div class="editor-label">
            <%= Html.LabelFor(model => model.CompanyName) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.CompanyName) %>
            <%= Html.ValidationMessageFor(model => model.CompanyName) %>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.ContactName) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.ContactName) %>
            <%= Html.ValidationMessageFor(model => model.ContactName) %>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.ContactTitle) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.ContactTitle) %>
            <%= Html.ValidationMessageFor(model => model.ContactTitle) %>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.Address) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.Address) %>
            <%= Html.ValidationMessageFor(model => model.Address) %>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.City) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.City) %>
            <%= Html.ValidationMessageFor(model => model.City) %>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.PostalCode) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.PostalCode) %>
            <%= Html.ValidationMessageFor(model => model.PostalCode) %>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.Country) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.Country) %>
            <%= Html.ValidationMessageFor(model => model.Country) %>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.Telephone) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.Telephone) %>
            <%= Html.ValidationMessageFor(model => model.Telephone) %>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.Fax) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.Fax) %>
            <%= Html.ValidationMessageFor(model => model.Fax) %>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.HomePage) %>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.HomePage) %>
            <%= Html.ValidationMessageFor(model => model.HomePage) %>
        </div>

        <p>
            <input type="submit" value="Save" />
        </p>
    </fieldset>

<% } %>

<div>
    <%= Html.ActionLink("Back to List", "Index") %>
</div>

Answer 1

猜猜你得到了一个例外。尝试在Try catch语句中抛出异常

try
{
    var originalSupplier = (from c in _entities.SupplierSet
                            where c.SupplierId == supplierToEdit.SupplierId
                            select c).FirstOrDefault();

    _entities.ApplyPropertyChanges(originalSupplier.EntityKey.EntitySetName, supplierToEdit);
    _entities.SaveChanges();
    // TODO: Add update logic here

    return RedirectToAction("Index");
}
catch(Exception ex)
{
    throw ex;
    return View();
}

因为我认为这是潜在的东西。

Answer 2

我会冒险猜测，并且在您尝试触发_entities方法时，您的ApplyPropertyChanges变量为空。

这会导致

对象引用未设置为对象的实例

错误抛出。

Answer 3

试试这个

    [AcceptVerbs(HttpVerbs.Post)]
  public ActionResult Edit(Supplier supplierToEdit)
{
    if (!ModelState.IsValid)
        return View();

    try
    {
        var originalSupplier = (from c in _entities.SupplierSet
                                where c.SupplierId == supplierToEdit.SupplierId
                                select c).FirstOrDefault();
  _entities.UpdateModel(originalSupplier);
        _entities.ApplyPropertyChanges(originalSupplier.EntityKey.EntitySetName, supplierToEdit);
        _entities.SaveChanges();
        // TODO: Add update logic here

        return RedirectToAction("Index");
    }
    catch
    {
        return View();
    }
}

在asp.net MVC 2应用程序中更新数据的问题

3 个答案: