CODEWITHSUNDEEP
vb.netrazorasp.net-mvc-4
dherrin79
dherrin79

Reputation: 377

dropdownlist returning null value to my controllers action result

Hi I am new to MVC and have looked through a great number of these posts and have not been able to solve my problem.

I have successfully populated my drop down list using a dropdownlistfor html helper, however when I submit the form the selected items value is not being passed with the model into the action result. In other words when I debug and examine the values the property for the dropdownlist is nothing. I believe that this is causing the "ModelState.isValid" to return false as well.

Here is my Model:

    Public Class Warranty

        Public Property state As DropDownList

        Private _States As IEnumerable(Of State)
        Public Property States As IEnumerable(Of State)
            Get
                If _States Is Nothing Then
                    _States = GetStates()
                End If
                Return _States
            End Get
            Set(value As IEnumerable(Of State))
                _States = value
            End Set
         End Property

        Public Shared Function GetStates() As List(Of State)
            Dim l As New List(Of State)
            l.Add(New State With {.Value = "none", .Text = "Selected One"})
            l.Add(New State With {.Value = "UT", .Text = "Utah"})
            l.Add(New State With {.Value = "NV", .Text = "Nevada"})
            Return l
        End Function
    End Class

Here is my State Class:

    Public Class State

        Public Property Value As String
        Public Property Text As String
    End Class

Here are my controller methods:

    ' GET: /Warranty
    Function WarrantyRegistration() As ActionResult
        ViewData("Message") = "Warranty Registration Form"
        Dim _statesList As New SoleWebSite.Models.Warranty
        Return View(_statesList)
    End Function

    '

    'POST: /Warranty
    <HttpPost()> _
    Function WarrantyRegistration(ByVal warranty As SoleWebSite.Models.Warranty) As ActionResult
        If ModelState.IsValid Then

            war.state = warranty.state.SelectedItem.Value.ToString()
            //  warranty.state



            db.AddTowarranty_registrations(war)
            db.SaveChanges()
            db.Dispose()

            Return RedirectToAction("WarrantyRegistration")
        End If
        Return View(warranty)
    End Function

Here is my view:

    <td>@Html.DropDownListFor(Function(m) m.state, New SelectList(Model.States, "Value", "Text"))</td>

I am not sure what I am doing wrong.

I would like to keep everything strongly typed and avoid using viewbag or viewdata if possible.

Any suggestion would be appreciated.

Thanks in advance.

Upvotes: 1

Views: 1114

Answers (1)

Darin Dimitrov
Darin Dimitrov

Reputation: 1038710

The selected value property should be a simple scalar type such as String or Integer and not a complex type such as DropDownList. By the way the DropDownList type is a classic WebForms server side control that has absolutely nothing to do in an ASP.NET MVC application. You should get rid of absolutely any reference to the System.Web.UI.WebControls namespace in an ASP.NET MVC application. So in your Warranty use a simple type:

Public Property state As String

and in your POST action you simply read the value:

<HttpPost()> _
Function WarrantyRegistration(ByVal warranty As SoleWebSite.Models.Warranty) As ActionResult
    If ModelState.IsValid Then
        war.state = warranty.state
        //  warranty.state
        db.AddTowarranty_registrations(war)
        db.SaveChanges()
        db.Dispose()
        Return RedirectToAction("WarrantyRegistration")
    End If
    Return View(warranty)
End Function

Upvotes: 1

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