我在VB中使用ASP.NET MVC。这是＆＃34; CreateStuffViewModel＆＃34;，这是我的＆＃34; Stuff＆＃34;的视图模型。类：
Public Property Name() As String
Public Property Description() As String
Public Property ItemNames() As List(Of String)
在创建资料的视图中，使用的模型是上面的视图模型。我有一个下拉组合框，其中包含所有用户项目的名称，这些项目是在Get中的控制器中创建的。用户可以选择组合框中的项目，然后点击＆＃34;添加＆＃34;按钮，将该文本添加到列表框中。当用户点击＆＃34;创建＆＃34;按钮，列表框中的文本项应该在ItemNames列表中。
这是Get函数：
' GET: Stuff/Create
Function Create() As ActionResult
Dim selectItem As New List(Of SelectListItem)
Dim curUserID = User.Identity.GetUserId()
Dim listOfItems = db.Items.Where(Function(x) x.MyUser.Id = curUserID)
For Each item In listOfItems
selectItem.Add(New SelectListItem() With {.Value = item.ID, .Text = item.Name})
Next
ViewData("selectItem") = selectItem
Dim newStuff As CreateStuffViewModel = New CreateStuffViewModel
newStuff.ItemNames = New List(Of String)
Return View(newStuff)
End Function
然后这是观点：
@ModelType CreateStuffViewModel
@Code
ViewData("Title") = "Create"
'This is the list of items that was created in the controller
Dim selectItem As New List(Of SelectListItem)
selectItem = ViewData("selectItem")
Dim selItems As New List(Of SelectListItem)
End Code
<h2>Create</h2>
@Using (Html.BeginForm())
@Html.AntiForgeryToken()
@<div class="form-horizontal">
<br />
<br />
<h4>Create a new Stuff</h4>
<hr />
@Html.ValidationSummary(True, "", New With { .class = "text-danger" })
<div class="form-group">
@Html.LabelFor(Function(model) model.Name, htmlAttributes:= New With { .class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(Function(model) model.Name, New With { .htmlAttributes = New With { .class = "form-control" } })
@Html.ValidationMessageFor(Function(model) model.Name, "", New With { .class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(Function(model) model.Description, htmlAttributes:= New With { .class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(Function(model) model.Description, New With { .htmlAttributes = New With { .class = "form-control" } })
@Html.ValidationMessageFor(Function(model) model.Description, "", New With { .class = "text-danger" })
</div>
</div>
@*This is the dropdown list containing the strings of item names*@
<div class="form-group">
<div class="control-label col-md-2" style="font-weight: bold">Select an existing Item</div>
<div class="col-md-10" id="ItemsList">
@Html.DropDownList("AvailItems", selectItem)
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="button" value="Add Item" class="btn btn-default" id="AddItem"/>
</div>
</div>
@*This is the list box to which the Add button adds the item text*@
<div class="form-group">
<div class="control-label col-md-2" style="font-weight: bold">Items in Stuff</div>
<div class="col-md-10">
@Html.ListBoxFor(Function(model) model.ItemNames, New SelectList(selItems), htmlAttributes:=New With {.name = "ItemNames"})
<div class="btn-group-vertical">
<div class="btn-link">Move Up</div>
<div class="btn-link">Move Down</div>
</div>
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="button" value="Remove Selected Item" class="btn btn-default" id="RemoveItem"/>
</div>
</div>
<br />
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Create" class="btn btn-default" />
</div>
</div>
</div>
End Using
<div>
@Html.ActionLink("Back to List", "Index")
</div>
@Section Scripts
@Scripts.Render("~/bundles/jqueryval")
@*Script for adding selected item from drop down to the list*@
<script>
$('#AddItem').click(function () {
var selection = $('#ItemsList :selected').text();
selection.trim();
var x = document.getElementsByName("ItemNames");
var i;
for (i = 0; i < x.length; i++) {
if (x[i].type == "select-multiple") { //listbox
x[i].options.add(new Option(selection, selection));
}
}
});
</script>
@*Script for removing selected item from list*@
<script>
$('#RemoveItem').click(function () {
var x = document.getElementsByName("ItemNames");
var listBox;
var i;
for (i = 0; i < x.length; i++) {
if (x[i].type == "select-multiple") { //listbox
listBox = x[i];
}
}
if (listBox.selectedIndex >= 0) {
var sel = listBox.options[listBox.selectedIndex];
listBox.options.remove(sel);
}
});
</script>
End Section
这是Post函数：
' POST: Stuff/Create
'To protect from overposting attacks, please enable the specific properties you want to bind to, for
'more details see http://go.microsoft.com/fwlink/?LinkId=317598.
<HttpPost()>
<ValidateAntiForgeryToken()>
Async Function Create(ByVal model As CreateStuffViewModel) As Task(Of ActionResult)
If ModelState.IsValid Then
Dim newStuff = New Stuff() With {
.Name = model.Name,
.Description = model.Description
}
Dim curUserID = User.Identity.GetUserId()
Dim thisUser As AppUser = db.Users.Where(Function(x) x.Id = curUserID).FirstOrDefault()
newStuff.MyUser = thisUser
'model.ItemNames is Nothing:
Dim thisList As List(Of String) = model.ItemNames
If thisList IsNot Nothing Then
Dim thisItem As Item
For Each item In thisList
thisItem = (From thing In db.Items Select thing Where thing.MyUser.Id = curUserID AndAlso thing.Name = item)
newStuff.Items.Add(thisItem)
Next
End If
db.Stuffs.Add(newStuff)
Await db.SaveChangesAsync()
Return RedirectToAction("Index")
End If
Return View(model)
End Function
因此视图工作正常 - “添加”按钮会按预期将文本添加到列表框中。但当我点击＆＃34;创建＆＃34;按钮，在控制器中，ItemNames列表没有，我不知道为什么。
非常感谢任何帮助！