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C# ASP.NET MVC Forms Improving Our Form Drop Down Lists

dodders
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dodders
Python Development Techdegree Graduate 38,679 Points
Posted by dodders
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dodders
Python Development Techdegree Graduate 38,679 Points

Issue with Challenge instructions? ASP.Net Forms

The challenge specifically states: Assume that a collection of select list items (of type SelectList) is available via the ViewBag.DepartmentsSelectListItems property.

However an error is raised if you do not explicitly cast ViewBag.DepartmentsSelectListItems to SelectList type.

Am I misunderstanding something, or is this is a mistake in the challenge?

Report.cshtml 
@model IssueReporter.Models.Issue

@{
    ViewBag.Title = "Report an Issue";
}

<h2>@ViewBag.Title</h2>

@using (Html.BeginForm())
{
    <div>
        @Html.LabelFor(m => m.Name)
        @Html.TextBoxFor(m => m.Name)
    </div>

    <div>
        @Html.LabelFor(m => m.Email)
        @Html.TextBoxFor(m => m.Email)
    </div>

    <div>
        @Html.LabelFor(m => m.DepartmentId)
        @Html.DropDownListFor(m => m.DepartmentId, (SelectList)ViewBag.DepartmentsSelectListItems)
    </div>

    <div>
        @Html.LabelFor(m => m.Severity)
        @Html.TextBoxFor(m => m.Severity)
    </div>

    <div>
        @Html.LabelFor(m => m.Reproducible)
        @Html.TextBoxFor(m => m.Reproducible)
    </div>

    <div>
        @Html.LabelFor(m => m.DescriptionOfProblem)
        @Html.TextAreaFor(m => m.DescriptionOfProblem)
    </div>

    <button type="submit">Save</button>
}

1 Answer

Steven Parker
Steven Parker
231,261 Points
Steven Parker
Steven Parker
231,261 Points

I believe the point of the instructions mentioning "(of type SelectList)" is so you'll know what type to cast it to. In fact, if you omit the cast, you get this response containing a more explicit hint:

Bummer: Did you cast the ViewBag.DepartmentsSelectListItems property to SelectList?

dodders
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
dodders
Python Development Techdegree Graduate 38,679 Points
dodders
.a{fill-rule:evenodd;}techdegree seal-36
dodders
Python Development Techdegree Graduate 38,679 Points

My interpretation was that the incoming list would already be of type SelectList.

But yes, as you say the challenge gives an obvious warning.

Steven Parker
Steven Parker
231,261 Points
Steven Parker
Steven Parker
231,261 Points

You're right that is already of that type. Casting doesn't change the type, it just lets the compiler know what it is so it can handle it properly.