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實施htmlAttributes MVC的DropDownListFor我有我的Register.Aspx View頁面下面的代碼如何使用VB
<div class="FieldDropDown">
<%: Html.DropDownListFor(Function(m) m.Question, ViewData("Questions"), New With {.style = "margin-bottom: 24px; font-family: Tahoma; font-size: 12pt; color: #333333;"})%>
<%: Html.ValidationMessageFor(Function(m) m.Question)%>
</div>
的問題是，它不斷彈出一個錯誤，我似乎無法準確地牽制如何執行代碼。
我沒有自己定義的任何自定義或額外的HTML Helpers，並且假定它應該工作而無需爲helper（？）方法擴展默認的內置MVC dropdownlist。
出現的錯誤...
Overload resolution failed because no accessible 'DropDownListFor' can be called without a narrowing conversion:
Extension method 'Public Function DropDownListFor(Of String)(expression As System.Linq.Expressions.Expression(Of System.Func(Of MvcApplication1.RegisterModel, String)), selectList As System.Collections.Generic.IEnumerable(Of System.Web.Mvc.SelectListItem), htmlAttributes As System.Collections.Generic.IDictionary(Of String, Object)) As System.Web.Mvc.MvcHtmlString' defined in 'System.Web.Mvc.Html.SelectExtensions': Argument matching parameter 'selectList' narrows from 'Object' to 'System.Collections.Generic.IEnumerable(Of System.Web.Mvc.SelectListItem)'.
Extension method 'Public Function DropDownListFor(Of String)(expression As System.Linq.Expressions.Expression(Of System.Func(Of MvcApplication1.RegisterModel, String)), selectList As System.Collections.Generic.IEnumerable(Of System.Web.Mvc.SelectListItem), htmlAttributes As System.Collections.Generic.IDictionary(Of String, Object)) As System.Web.Mvc.MvcHtmlString' defined in 'System.Web.Mvc.Html.SelectExtensions': Argument matching parameter 'htmlAttributes' narrows from '<anonymous type> (line 149)' to 'System.Collections.Generic.IDictionary(Of String, Object)'.
Extension method 'Public Function DropDownListFor(Of String)(expression As System.Linq.Expressions.Expression(Of System.Func(Of MvcApplication1.RegisterModel, String)), selectList As System.Collections.Generic.IEnumerable(Of System.Web.Mvc.SelectListItem), htmlAttributes As Object) As System.Web.Mvc.MvcHtmlString' defined in 'System.Web.Mvc.Html.SelectExtensions': Argument matching parameter 'selectList' narrows from 'Object' to 'System.Collections.Generic.IEnumerable(Of System.Web.Mvc.SelectListItem)'.
當我刪除HTMLATTRIBUTES下面的下面的代碼，然後它工作正常，沒有出現任何錯誤，但再也不是風格DropDownList的，它只是看起來平淡沒有CSS格式，我想有就可以了...
<div class="FieldDropDown">
<%: Html.DropDownListFor(Function(m) m.Question, ViewData("Questions"))%>
<%: Html.ValidationMessageFor(Function(m) m.Question)%>
</div>
我想要了解的是...
我需要延長HTMLHELP呃下拉列表？ 我需要在我的控制器代碼中添加一些東西嗎？
我的控制器代碼如下...
<Required()> _
Public Property Question() As String
Get
Return _Question
End Get
Set(value As String)
_Question = value
End Set
End Property
在正確的方向或引用鏈接任何指針將是有益的。 謝謝
編輯
下面這段代碼是在賬戶控制器我Reagister ACTION內。
'-> Okay
Item0 = NewQuestion("0", "Please select an option", True)
Item1 = NewQuestion("1", "What was your mothers maiden name?", False)
Item2 = NewQuestion("2", "Where were you born?", False)
Item3 = NewQuestion("3", "What was the name of your first love?", False)
Item4 = NewQuestion("4", "What was the name of your favourite pet?", False)
Item5 = NewQuestion("5", "What is the name of your favourite song?", False)
Item6 = NewQuestion("6", "What is the name of your idol/mentor?", False)
Item7 = NewQuestion("7", "What model of your first car?", False)
Item8 = NewQuestion("8", "What model was your first motorcycle?", False)
Item9 = NewQuestion("9", "Who is your favourite sports-person?", False)
Item10 = NewQuestion("10", "What was your last ACTIVATION KEY?", False)
SQuestions = Nothing
SQuestions = New SelectList({Item0, Item1, Item2, Item3, Item4, Item5, Item6, Item7, Item8, Item9, Item10}, Item0)
Session("Website_Guest") = ThisGuest
ViewData("VisitorName") = ThisGuest.Username
'ViewData("Questions") = New SelectList(SQuestions.Items) <- TRIED IT LIKE THIS TOO
'ViewData("Questions") = New SelectList(SQuestions) <- TRIED IT LIKE THIS TOO
ViewData("Questions") = sQuestions
ViewData("PasswordLength") = MembershipService.MinPasswordLength
Return View()
這是NEWQUESTION功能這在本質上
Private Function NewQuestion(NewValue As String, NewData As String, NewSelected As Boolean) As SelectListItem
Dim Item As SelectListItem = Nothing
Item = Nothing
If Trim(NewValue) <> "" Then
If Trim(NewData) <> "" Then
Item = New SelectListItem()
Item.Value = NewValue
Item.Text = NewData
Item.Selected = NewSelected
End If
End If
Return Item
Item = Nothing
End Function
所以輸出selectlistitem，我傳遞一個選擇列表的一審所以這就是爲什麼我沒扔在別的選擇列表的 - 雖然像我在評論它確實解決了造型，但給我留下了另一個問題重新說：下面的照片顯示了我得到..
Closing
謝謝大家幫我解決這個問題，我已經標記了其中一個答案，因爲人們的答案幫助我指出了問題，它不一定意味着其他答案是錯誤的，它可能是我的缺點理解比什麼都重要。
要解決此問題我再次查看了傳遞viewdata的方式，儘管我通過SELECTLIST傳遞了一個SELECTLIST.ITEMS集合，然後在VIEW中將傳遞的數據重新傳遞給了一個selectlist，現在數據可見而不是選擇列表對象，並且它在HTML.DROPDOWNLISTFOR方法中附加了HTMLATTRIBUTES。
謝謝大家。
也許問題的構造與ViewData的（作爲參數傳遞 「問題」）。檢查http://msdn.microsoft.com/en-us/library/ee834953%28v=vs.108%29.aspx – Brij