I'm trying to use a SelectList one of my views, and its just not populating correctly. It gets the proper number of entries (4), but they all read System.Web.Mvc.SelectListItem. I fired up the debugger on the code, and saw some strangeness going on. I must be doing something wrong, but I don't quite see what.
Code from the ViewModel:
public SelectList DeviceTypes {get; private set;}
....
var device_types = DataTableHelpers.DeviceTypes();
IEnumerable<SelectListItem> sl = device_types.Select(
dt => new SelectListItem { Selected = (dt.DeviceType == 1),
Text = dt.Description,
Value = dt.DeviceType.ToString() }).ToList();
DeviceTypes = new SelectList(sl);
And code from the View:
<%= Html.DropDownList("Type",Model.DeviceTypes) %>
So, when I look at this in the debugger, the sl IEnumerable is getting built correctly. I can see all 4 elements in there, with the proper Text and Value property values. Once I call the SelectList constructor however, if I expand the IEnumerable that it contains, I see that it has 4 entries, but all the data in them has been lost. The Text is set to System.Web.Mvc.SelectListItem, and the value is null.
Ive tried changing the ToList() call to a ToArray(), as well as removing it entirely. That didn't change the behaviour.
What am I doing wrong here?
EDIT: Scratch my first answer.
You should be passing the IEnumerable list if items to the View, not trying to construct a Html item in the controller.
Code for controller:
public IEnumberable<YourModel> DeviceTypes {get; internal set;}
....
DeviceTypes = DataTableHelpers.DeviceTypes();
Code for View:
<%= Html.DropDownList("Type", from dt in Model.DeviceTypes
select new SelectListItem
{
Text = dt.Description,
Value = dt.DeviceType.ToString(),
Selected = dt.DeviceType == 1
}) %>
Related
A common way to fill a table is:
#For Each item In Model
Dim currentItem = item
#<tr>
<td>currentitem.Data1</td>
<td>currentitem.Data2</td>
<td>currentitem.Data3</td>
</tr>
Next
But for some reasons (to control the order of columns), I would like to refer to the fields by their string names, something like this:
#For Each item In Model
Dim currentItem = item
#<tr>
<td>currentitem("Data1").Value</td>
<td>currentitem("Data2").Value</td>
<td>currentitem("Data3").Value</td>
</tr>
Next
Is it somehow possible?
Ok - now that we have established that you need to change the order of your view model, let's do a little bit of work to your view model to make it easier to change the order. Given that we have to change the order of how we display things, we have to have a way to track what order to display them in. To change on the fly in the view without having different views with different orders (could get messy fast) - so let's just update our model a little bit.
Let assume this is your view model
public class OriginalViewModel{
public string Data1 {get;set;}
public string Data2 {get;set;}
public string Data3 {get;set;|
}
Let's create a new class called DataProperty. This will hold the data objects as well as allow us to set a display order that we can sort on later.
public class DataProperty{
public int DisplayOrder {get;set;}
public string Data {get;set;}
}
Now, let's update your view model to be a set of these DataProperties. We are using something we can enumerate and order by the display order.
public class UpdatedViewModel{
public IEnumerable<DataProperty> DataSet {get;set;}
}
Now, you can set the display order on each one of your property elements.
var listOfItems = new List<DataProperty>();
listOfItems.Add(new DataProperty{Data = "data1", DisplayOrder = 2});
listOfItems.Add(new DataProperty{Data = "data2", DisplayOrder = 3});
listOfItems.Add(new DataProperty{Data = "data3", DisplayOrder = 1});
var model = new UpdatedViewModel();
model.Data = listOfItems;
In your view, order by the display order property. Note we can now use Linq to order our data appropriately based on the requirements for this view.
#{foreach(var item in Model.OrderBy(x=>x.Data.DisplayOrder){
<tr>
<td>#item.Data</td>
<td>#item.Data</td>
<td>#item.Data</td>
</tr>
}}
which should render in HTML
<tr>
<td>data3</td>
<td>data1</td>
<td>data2</td>
</tr>
Thank you Tommy,
I tried to solve it in simple way and did this:
For example, I have a Viewdata that contains the order of the columns:
ViewData("columnsorder")="|3|1|2|"
and then, I just loop through ViewData and set the columns.
#For Each item In Model
Dim currentItem = item
#<tr>
#For i As Integer = 1 To ViewData("columnsorder").ToString.Split("|").Count - 2
Dim ind As Integer = ViewData("columnsorder").ToString.Split("|")(i)
Select Case ind
Case 1#<td>#currentItem.Data1</td>
Case 2#<td>#currentItem.Data2</td>
Case 3#<td>#currentItem.Data3</td>
End Select
Next
</tr>
Next
I have converted my MVC3 application to MVC5, I had to change all views to razor. Having a challenge with a select list:
In ASPX view that works I am using the following:
<select id="Profession" name="Profession" style="width: 235px; background-color: #FFFFCC;">
<% List<string> allProfessions = ViewBag.AllProfessions;
string selectedProfession;
if (Model != null && !String.IsNullOrEmpty(Model.Profession))
selectedProfession = Model.Profession;
else
selectedProfession = allProfessions[0];
foreach (var aProfession in allProfessions)
{
string selectedTextMark = aProfession == selectedProfession ? " selected=\"selected\"" : String.Empty;
Response.Write(string.Format("<option value=\"{0}\" {1}>{2}</option>", aProfession, selectedTextMark, aProfession));
}%>
</select>
In Razor I am using:
<select id="Profession" name="Profession" style="width: 235px; background-color: #FFFFCC;">
#{List<string> allProfessions = ViewBag.AllProfessions;
string selectedProfession;}
#{if (Model != null && !String.IsNullOrEmpty(Model.Profession))
{selectedProfession = Model.Profession;}
else {selectedProfession = allProfessions[0];}
}
#foreach (var aProfession in allProfessions)
{
string selectedTextMark = aProfession == selectedProfession ?
"selected=\"selected\"" : String.Empty;
Response.Write(string.Format("<option value=\"{0}\" {1}>{2}</option>",
aProfession, selectedTextMark, aProfession));
}
</select>
The list shows up at the top of the page, I can't figure out where is the problem. Would appreciate your assistance.
Don't create your dropdown manually like that. Just use:
#Html.DropDownListFor(m => m.Profession, ViewBag.AllProfessions, new { style = "..." })
UPDATE
I tried your solution but got this error: Extension method cannot by dynamically dispatched
And, that's why I despise ViewBag. I apologize, as my answer was a little generic. Html.DropDownList requires the list of options parameter to be an IEnumerable<SelectListItem>. Since ViewBag is a dynamic, the types of its members cannot be ascertained, so you must cast explicitly:
(IEnumerable<SelectListItem>)ViewBag.AllProfessions
However, your AllProfessions is a simple array, so that cast won't work when the value gets inserted at run-time, but that can be easily fixed by casting it to a List<string> and then converting the items with a Select:
((List<string>)ViewBag.AllProfessions).Select(m => new SelectListItem { Value = m, Text = m })
There again, you see why dynamics are not that great, as that syntax is rather awful. The way you should be handling this type of stuff is to use your model or, preferably, view model to do what it should do: hold domain logic. Add a property to hold your list of profession choices:
public IEnumerable<SelectListItem> ProfessionChoices { get; set; }
And then, in your controller action, populate this list before rendering the view:
var model = new YourViewModel();
...
model.ProfessionChoices = repository.GetAllProfessions().Select(m => new SelectListItem { Value = m.Name, Text = m.Name });
return View(model);
repository.GetAllProfessions() is shorthand for whatever you're using as the source of your list of professions, and the Name property is shorthand for how you get at the text value of the profession: you'll need to change that appropriately to match your scenario.
Then in your view, you just need to do:
#Html.DropDownListFor(m => m.Profession, Model.ProfessionChoices)
Given that you don't have this infrastructure already set up, it may seem like a lot to do just for a drop down list, and that's a reasonable thing to think. However, working in this way will keep your view lean, make maintenance tons easier, and best of all, keep everything strongly-typed so that if there's an issue, you find out at compile-time instead of run-time.
I believe it's happening because of the Response.Write. Try this:
#Html.Raw(string.Format("<option value=\"{0}\" {1}>{2}</option>", aProfession,
selectedTextMark, aProfession))
I have a table that contains a list of EquipmentIDs and another table that has maintenance records.
When the user edits a maintenance record I want there to be a drop down list of all of the equipment IDs from the table.
The dropdown list populates, and it populates with the correct amount of entries, however they all say System.Web.MVC.SelectListItem instead of the value of the ID.
Here is the code that generates the list:
public ActionResult Edit(int id)
{
MaintPerformed maintPerformed = maintPerformedRepository.GetMaintPerformed(id);
IList<EquipmentID> IDs = equipmentIDRepository.GetEquipmentIDAsList();
IEnumerable<SelectListItem> selectEquipList =
from c in IDs
select new SelectListItem
{
//Selected = (c.EquipID == maintPerformed.EquipID),
Text = c.EquipID,
Value = c.Sort.ToString()
};
ViewData["EquipIDs"] = new SelectList(selectEquipList, maintPerformed.ID);
return View(maintPerformed);
}
Here is the entry in the .aspx page for the Dropdown list:
%: Html.DropDownList("EquipIDs") %>
Here is how I am generating the list from the table:
public List<EquipmentID> GetEquipmentIDAsList()
{
return db.EquipmentIDs.ToList();
}
It appears that everything is working correctly with the exception of assigning the text to be displayed in the drop down box.
What am I missing or not thinking correctly about?
SelectList and SelectListItem are actually mutually exclusive. You should be using one or the other. Etiher pass the constructor of SelectList your raw data (IDs) or don't use SelectList at all and just make ViewData["EquipIDs"] your enumerable of SelectListItem. If you go with the latter approach, you will have to tweak your code so that you are setting the selected item in the constructor of SelectListItem (as you had done, but commented out).
Either:
ViewData["EquipIDs"] = new SelectList(IDs, maintPerformed.ID, "EquipID", "Sort");
Or:
IEnumerable<SelectListItem> selectEquipList =
from c in IDs
select new SelectListItem
{
Selected = c.EquipID == maintPerformed.EquipID,
Text = c.EquipID,
Value = c.Sort.ToString()
};
ViewData["EquipIDs"] = selectEquipList;
have looked at Phil Haacks project on books at
http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx
which has been useful, but I have a mix of data types.
I use a modelview so that i can have a mix of objects, in this case: Order (ie order.id, order.date etc), Customer, SoilSamplingOrder and a list of SoilSamplingSubJobs which is like this [0].id, [0].field, [1].id, [1].field etc
Perhaps I should be using ICollection instead of List? I had problems getting UpdateModel to work so I used an extract from collection method. the first 4 method calls : orderRepository.FindOrder(id); etc give the model the original to be edited. but after this point i'm a little lost in how to update the subjobs. I hope i have delineated enough to make sense of the problem.
[HttpPost]
public ActionResult Edit(int id, FormCollection collection)
{
Order order = orderRepository.FindOrder(id);
Customer cust = orderRepository.FindCustomer(order.customer_id);
IList<SoilSamplingSubJob> sssj = orderRepository.FindSubOrders(id);
SoilSamplingOrder sso = orderRepository.FindSoilSampleOrder(id);
try
{
UpdateModel(order, collection.ToValueProvider());
UpdateModel(cust, collection.ToValueProvider());
UpdateModel(sso, collection.ToValueProvider());
IList<SoilSamplingSubJob> sssjs = orderRepository.extractSSSJ(collection);
foreach (var sj in sssjs)
UpdateModel(sso, collection.ToValueProvider());
orderRepository.Save();
return RedirectToAction("Details", new { id=order.order_id});
}
catch
{
return View();
}
}
I think you should work on developing a view model that reflects the data that you need to get back and create display/edit templates for that model that renders the view model using Phil Haack's methods for your lists of objects -- in this case, arrays of submodel classes. Let the model binding framework build the returned model (as a parameter) to your action, then reconstitute your domain models from the view model data. Brad Wilson has an excellent series of articles on templating that should be helpful.
I use IModelBinder on my complex classes. You don't need IModelBinder, but it will make your controller post codeblock look much cleaner. I'm using VB at the moment, but my class looks something like this for example:
Public Class CombinedRulesAndXmlRules : Implements IModelBinder
Public Rules As New Rules()
Public XmlRules As New XmlRules()
Public RequiredTemplates As New List(Of RequiredTemplates)
Public SearchCriteria As New List(Of SearchCriteriaList)
Public OptionalTemplates As New List(Of OptionalTemplates)
Public Questions As New List(Of Questions)
Public QATemplates As New List(Of QATemplates)
**Public Answers As New List(Of Answers)**
Now I don't use editor templates in my views, so to have your lists appear in the formcollection you have to add something like this in your view:
#For x As Integer = 0 To Model.Answers.Count - 1
Dim incr As Integer = x
#Html.HiddenFor(Function(model) model.Answers(incr).Answer)
#Html.HiddenFor(Function(model) model.Answers(incr).AnswerId)
#Html.HiddenFor(Function(model) model.Answers(incr).AnswerTemplateTag)
#Html.HiddenFor(Function(model) model.Answers(incr).Tag)
Next
When the view is submitted/posted, the model binder takes over before hitting the first line of code in your mvc post controller method. I then iterate through the actual formcollection and strip out the [#] using regex, because your formcollection will show your list items like this: Answers[0].Answer, Answers[0]AnswerId ,etc.:
For x As Integer = 1 To request.Form.Count - 1
keyname = request.Form.Keys(x)
Debug.Write(keyname)
val = request.Form(x).ToString()
'If keyname contains [#] strip it. it's a list item.
Dim pattern As String = "\[(\d+)\]"
Dim iterpattern As String = "\d+"
Dim rgx As New Regex(pattern)
Dim rgxiter As New Regex(iterpattern)
If Regex.IsMatch(keyname, pattern) Then
Dim match As Match = rgxiter.Match(keyname)
ListIteration = CInt(match.Value)
Dim result As String = rgx.Replace(keyname, "")
keyname = result
End If
The Select Case codeblock is next. So you already know you have a strong typed class in your model, so your select can look like this:
Select Case keyname
Case "Answers.Answer"
'add code here to add to your return list. What you
'get in the post controller is a fully populated class.
All,
I've read through a lot of posts about Checkboxes and ASP.MVC but I'm not that much wiser.
My scenario:
I have a strongly typed View where I pass a collection of summary objects to the view for rendering in a for-each. This summary object contains label data based on a unique id. I also add a checkbox to the row so do so via:
<td>
<%= Html.CheckBox("markedItem", Model.MarkedItem, new { TrackedItemId = Model.Id })%>
</td>
When I perform a POST to get the submitted results my action method takes the strongly typed ViewModel back but the original summary object that I used to create the list is not populated.
Ok, this is annoying, but I can understand why so I'll live with it.
What I then do is to add a new property to my ViewModel called "MarkedItem" which is a string collection.
On postback this marked item is filled with the before and after states if the checkbox has changed but nothing to tell me which key they were for. Just to clarify, if I send this
TrackedItemId = A, Value = false
TrackedItemId = B, Value = true
TrackedItemId = C, Value = false
and set the page to this:
TrackedItemId = A, Value = true
TrackedItemId = B, Value = true
TrackedItemId = C, Value = false
I will get back this:
MarkedItem[0] = true
MarkedItem[1] = false
MarkedItem[2] = true
MarkedItem[3] = false
in other words [0] is the new value and [1] is the old value, [2] and [3] represent values that haven't changed.
My questions are:
Is this right - that I get before and after in this way? Is there any way to only send the latest values?
How can I get hold of the custom attribute (TrackedItemId) that I've added so that I can add meaning to the string array that is returned?
So far I like MVC but it not handling simple stuff like this is really confusing. I'm also a javascript noob so I really hope that isn't the answer as I'd like to return the data in my custom viewmodel.
Please make any explanations/advice simple :)
<p>
<label>
Select project members:</label>
<ul>
<% foreach (var user in this.Model.Users)
{ %>
<li>
<%= this.Html.CheckBox("Member" + user.UserId, this.Model.Project.IsUserInMembers(user.UserId)) %><label
for="Member<%= user.UserId %>" class="inline"><%= user.Name%></label></li>
<% } %></ul>
and in the controller:
// update project members
foreach (var key in collection.Keys)
{
if (key.ToString().StartsWith("Member"))
{
int userId = int.Parse(key.ToString().Replace("Member", ""));
if (collection[key.ToString()].Contains("true"))
this.ProjectRepository.AddMemberToProject(id, userId);
else
this.ProjectRepository.DeleteMemberFromProject(id, userId);
}
}
With thanks to Pino :)
ok, one hack I've come up with - I really hate that I have to do this but I don't see another way round it and I'm sure it will break at some point.
I've already implemented by own ModelBinder to get round some other issues (classes as properties for example) so have extended it to incorporate this code. We use Guid's for all our keys.
If there are any alternatives to the below then please let me know.
Html
<%= Html.CheckBox("markedItem" + Model.Id, false)%>
C#
(GuidLength is a const int = 36, Left and Right are our own string extensions)
//Correct checkbox values - pull all the values back from the context that might be from a checkbox. If we can parse a Guid then we assume
//its a checkbox value and attempt to match up the model. This assumes the model will be expecting a dictionary to receive the key and
//boolean value and deals with several sets of checkboxes in the same page
//TODO: Model Validation - I don't think validation will be fired by this. Need to reapply model validation after properties have been set?
Dictionary<string, Dictionary<Guid, bool>> checkBoxItems = new Dictionary<string, Dictionary<Guid, bool>>();
foreach (var item in bindingContext.ValueProvider.Where(k => k.Key.Length > GuidLength))
{
Regex guidRegEx = new Regex(#"^(\{{0,1}([0-9a-fA-F]){8}-([0-9a-fA-F]){4}-([0-9a-fA-F]){4}-([0-9a-fA-F]){4}-([0-9a-fA-F]){12}\}{0,1})$");
if (guidRegEx.IsMatch(item.Key.Right(GuidLength)))
{
Guid entityKey = new Guid(item.Key.Right(GuidLength));
string modelKey = item.Key.Left(item.Key.Length - GuidLength);
Dictionary<Guid, bool> checkedValues = null;
if (!checkBoxItems.TryGetValue(modelKey, out checkedValues))
{
checkedValues = new Dictionary<Guid, bool>();
checkBoxItems.Add(modelKey, checkedValues);
}
//The assumption is that we will always get 1 or 2 values. 1 means the contents have not changed, 2 means the contents have changed
//and, so far, the first position has always contained the latest value
checkedValues.Add(entityKey, Convert.ToBoolean(((string[])item.Value.RawValue).First()));
}
}
foreach (var item in checkBoxItems)
{
PropertyInfo info = model.GetType().GetProperty(item.Key,
BindingFlags.IgnoreCase |
BindingFlags.Public |
BindingFlags.Instance);
info.SetValue(model, item.Value, null);
}