Question

I am using the following action to save Nav Bar Items edited from with admin of a content management system:

    [HttpPost]
    public ActionResult aSaveNavs()
    {
        aLoggedIn();

        NavItemsDataContext navDB = new NavItemsDataContext();
        Nav n = navDB.Navs.Select(row => row.ID == Convert.ToInt32(Request.Form["ID"]));

        n.NavName = Request.Form["NavName"];
        n.NavURL = Request.Form["NavURL"];
        n.NavEnabled = (Request.Form["NavEnabled"] == "true" ? true : false);
        navDB.SubmitChanges();

        return Redirect("/Admin/aHome");
    }

I am using the following view:

@{
List<Nav> navList = HtmlHelpers.GetNavList();
}

@foreach (Nav item in navList)
{
    <tr>
        <td style="width: 150px; text-align: center;">
            @item.NavName
        </td>
        <td style="width: 150px; text-align: center;">
            <input id="NavName" name="NavName" type="text" value="@item.NavName" />
        </td>
        <td style="width: 150px; text-align: center;">
            <input id="NavURL" name="NavURL" type="text" value="@item.NavURL" />
        </td>
        <td>
            <input id="ID" name="ID" type="text" readonly="readonly" value="@item.ID" />
        </td>
    </tr>
}

Obviously the view has a few other bits in but this is the section in question.

When I try and save my changes, I get “System.FormatException: Input string was not in a correct format.” and the following line is highlighted:

Nav n = navDB.Navs.FirstOrDefault(row => row.ID == Convert.ToInt32(Request.Form["ID"]));

Thanks in advance for any help with this.

Answer 1

Convert.ToInt32 may still throw an error, for example when it is empty, therefore use this:

int result=0;
Int32.TryParse(Request.Form["ID"].ToString(), out result);

and then in your code:

Nav n = navDB.Navs.FirstOrDefault(row => row.ID == result);