看起来像 MVC 4 Razor“for”循环中的错误？

Question

我正在使用 Microsoft ASP.NET MVC 4 版本 4.0.30.506.0 编写 MVC4，并且我在 razor 页面中有一个 for 循环，它会生成一个愚蠢的运行时错误！

这是我写的代码：

@{
                    if (Model.IsAuction)
                    {
                        <li class="bc49">@Html.ActionLink("ABCD", "Search", "Home", new {city = "all", type = "auction", category = "all", keyword = "all", condition = "all", sort = "asc"})</li>
                    }
                    else
                    {
                        <li class="bc49">@Html.ActionLink("EFGH", "Search", "Home", new {city = "all", type = "product", category = "all", keyword = "all", condition = "all", sort = "asc"})</li>
                    }

                    int crumpsCount = 48;

                    for (int i = 0; i < Model.Categories.Count; i++)
                    {
                        className = "bc" + crumpsCount;

                        if (Model.IsAuction)
                        {
                            <li class="@className">@Html.ActionLink(Model.Categories[i].Title, "Search", "Home", new {city = "all", type = "auction", category = Model.Categories[i].Name, keyword = "all", condition = "all", sort = "asc"})</li>
                        }
                        else
                        {
                            <li class="@className">@Html.ActionLink(Model.Categories[i].Title, "Search", "Home", new {city = "all", type = "product", category = Model.Categories[i].Name, keyword = "all", condition = "all", sort = "asc"})</li>
                        }

                        crumpsCount--;
                    }
                }

这是由 Visual Studio 2012 生成的错误：

错误发生在循环结束并且 i 的值等于 Model.Categories.Count 之后。似乎编译器试图访问 Model.Categories[Model.Categories.Count] 值！

有趣的事实是，当我用 foreach 循环替换这段代码时，或者即使我在 for 循环之后添加一个 foreach 循环，代码也会正确执行并通过 for 循环！

这是有效的代码：

@{
                    if (Model.IsAuction)
                    {
                        <li class="bc49">@Html.ActionLink("ABCD", "Search", "Home", new {city = "all", type = "auction", category = "all", keyword = "all", condition = "all", sort = "asc"})</li>
                    }
                    else
                    {
                        <li class="bc49">@Html.ActionLink("EFGH", "Search", "Home", new {city = "all", type = "product", category = "all", keyword = "all", condition = "all", sort = "asc"})</li>
                    }

                    int crumpsCount = 48;

                    for (int i = 0; i < Model.Categories.Count; i++)
                    {
                        className = "bc" + crumpsCount;

                        if (Model.IsAuction)
                        {
                            <li class="@className">@Html.ActionLink(Model.Categories[i].Title, "Search", "Home", new {city = "all", type = "auction", category = Model.Categories[i].Name, keyword = "all", condition = "all", sort = "asc"})</li>
                        }
                        else
                        {
                            <li class="@className">@Html.ActionLink(Model.Categories[i].Title, "Search", "Home", new {city = "all", type = "product", category = Model.Categories[i].Name, keyword = "all", condition = "all", sort = "asc"})</li>
                        }

                        crumpsCount--;
                    }

                    foreach (CategoryInfo categoryInfo in Model.Categories)
                    {
                        className = "bc" + crumpsCount;

                        if (Model.IsAuction)
                        {
                            <li class="@className">@Html.ActionLink(categoryInfo.Title, "Search", "Home", new {city = "all", type = "auction", category = categoryInfo.Name, keyword = "all", condition = "all", sort = "asc"})</li>
                        }
                        else
                        {
                            <li class="@className">@Html.ActionLink(categoryInfo.Title, "Search", "Home", new {city = "all", type = "product", category = categoryInfo.Name, keyword = "all", condition = "all", sort = "asc"})</li>
                        }

                        crumpsCount--;
                    }
                }

我刚刚分享了这段代码，看看这是否是一个错误，如果它是一个错误，它是否是已知的。

感谢大家。 :)

更新： 太傻了，现在代码也不能用foreach循环了！

foreach 循环内没有索引，但异常提到索引超出范围！

代码如下：

foreach (CategoryInfo categoryInfo in Model.Categories)
                    {
                        className = "bc" + crumpsCount;

                        if (Model.IsAuction)
                        {
                            <li class="@className">@Html.ActionLink(categoryInfo.Title, "Search", "Home", new {city = "all", type = "auction", category = categoryInfo.Name, keyword = "all", condition = "all", sort = "asc"})</li>
                        }
                        else
                        {
                            <li class="@className">@Html.ActionLink(categoryInfo.Title, "Search", "Home", new {city = "all", type = "product", category = categoryInfo.Name, keyword = "all", condition = "all", sort = "asc"})</li>
                        }

                        crumpsCount--;
                    }

我还应该提到 Model.Categories 是一个 IList 对象。

Answer 1

问题解决了。 MVC 中没有我看到的错误，但是在 MVC/Razor 运行时中引用了错误的异常，它引用了确切错误位置上方的一行，让我认为框架的运行时中存在错误。 真正的异常是关于一个从数据库返回为空的数组，而我编写的代码试图访问该数组的索引 0，因此我的代码中有一个超出范围的异常，但该异常引用了 10 行以上我写的确切访问代码，所以我认为这将是一个错误。 感谢 cmets 的回复，希望这对以后的人有所帮助。