I found many questions and answers related to this issue but nothing worked for me
I am creating a dropdown list like this
#Html.DropDownListFor(m => m.SchoolYears, new SelectList(Model.SchoolYears, "YearId", "StartDates", Model.CurrentYearId), new { #class = "field_Dropdown", style = "width:100px;",onchange="return searchStudents();" })
(Model.CurrentYearId is of type int)
But it never lets current year selected.
From this post, I got that we should use string for selected value (although I don't know why because it allows object for selected value)
DropDownList SelectList SelectedValue issue
so I tried all these variations
new SelectList(Model.SchoolYears, "YearId", "StartDates", Model.CurrentYearId.ToString())
new SelectList(Model.SchoolYears, "YearId", "StartDates", 2)
new SelectList(Model.SchoolYears, "YearId", "StartDates", "2")
But they even didn't work.
There is way to create the select list through linq query or foreach loop and mark selected property of each item but why the above doesn't work?
Found the problem.
The mistake I was doing is using this
m => m.SchoolYears // m.SchoolYears in a list of string
When I changed it to this
m => m.SelectedYearId // m.SelectedYearId is an integer property
it worked like a charm, so finally I have this working
#Html.DropDownListFor(m => m.SelectedYearId, new SelectList(Model.SchoolYears, "YearId", "StartDates", Model.CurrentYearId), new { #class = "field_Dropdown", style = "width:100px;",onchange="return searchStudents();" })
Thanks!
The solution did not work for me. It turns out selected property doesnot work if the ViewBag Property name and Model Property name is same so after changing the ViewBag Property name it worked.
Related
I have a basic enum for gender with value assignemnts 1, 2 for male and female. This code worked for me in previous mvc, but I am getting errors in asp.net core
any pointers as whats wrong ?
thanks
#Html.DropDownListFor(c => c.Gender, Enum.GetValues(typeof(Accounts.i_EF.Accounts.Gender)).Cast<Accounts.i_EF.Accounts.Gender>().Select(c => SelectListItem { Text = c.ToString(), Value = c.ToString() } ))
if you are using MVC6, there is one method GetEnumSelectList which can be used to create the dropdown.
<select asp-for="Gender" asp-items="Html.GetEnumSelectList<Gender>()">
</select>
For your previous code, try to change to
#Html.DropDownListFor(c => c.Gender, Enum.GetValues(typeof(Gender)).Cast<Gender>().Select(c => new SelectListItem { Text = c.ToString(), Value = c.ToString() } ))
Ensure that your project is referencing 'Microsoft.NET.Sdk.Web' and the 'PreserveCompilationContext' property is not set to false.
For this, try to clean and rebuild your project. If not work, restart your VS.
Iam passing a viewbag to view as a selectlist as below
ViewBag.Currency = new SelectList(db.portal_lookup.Where(c => c.lookup_type
== "FND_CURRENCY").OrderBy(m => m.lookup_description), "lookup_id", "lookup_description");
in view i show it as below
#Html.DropDownListFor(model => model.currency_code,
(SelectList)#ViewBag.Currency,"",new { #class = "m-wrap" })
by default the value of this dropdownlistfor should be "IND" how can i set that?
Your best bet is probably to fill up the model that you pass to the view, assuming that you're passing one, whereby you set
model.currency_code = "IND".
Alternatively, you could use the overload for new SelectList that allows you to specify the selected value:
SelectList Constructor (IEnumerable, String, String, Object)
Initializes a new instance of the SelectList class by using the specified items for the list, the data value field, the data text field, and a selected value.
ViewBag.Currency = new SelectList(db.portal_lookup.Where(c => c.lookup_type == "FND_CURRENCY").OrderBy(m => m.lookup_description), "lookup_id", "lookup_description", "IND");
Hope that helps.
My model contains an array of zip code items (IEnumerable<SelectListItem>).
It also contains an array of selected zip codes (string[]).
In my HTML page, I want to render each selected zip code as a drop down with all the zip code options. My first attempt did not work:
#foreach (var zip in Model.ZipCodes) {
Html.DropDownList( "ZipCodes", Model.ZipCodeOptions )
}
I realized that although that would produce drop downs with the right "name" attribute, it wouldn't know which element of ZipCodes holds the value for that particular box, and might just default to the first one.
My second attempt is what really surprised me. I explicitly set the proper SelectListItem's Selected property to true, and it still rendered a control with nothing selected:
#foreach (var zip in Model.ZipCodes) {
Html.DropDownList( "ZipCodes", Model.ZipCodeOptions.Select( x => (x.Value == zip) ? new SelectListItem() { Value = x.Value, Text = x.Text, Selected = true } : x ) )
}
There, it's returning a new IEnumerable<SelectListitem> that contains all the original items, unless it's the selected item, in which case that element is a new SelectListItem with it's Selected property set to true. That property is not honored at all in the final output.
My last attempt was to try to use an explicit index on the string element I wanted to use as the value:
#{int zipCodeIndex = 0;}
#foreach (var zip in Model.ZipCodes) {
Html.DropDownList( "ZipCodes[" + (zipCodeIndex++) + "]", Model.ZipCodeOptions )
}
That doesn't work either, and probably because the name is no longer "ZipCodes", but "ZipCodes[x]". I also received some kind of read-only-collection error at first and had to change the type of the ZipCodes property from string[] to List<string>.
In a forth attempt, I tried the following:
#for (int zipCodeIndex = 0; zipCodeIndex < Model.ZipCodes.Count; zipCodeIndex++)
{
var zip = Model.ZipCodes[zipCodeIndex];
Html.DropDownListFor( x => x.ZipCodes[zipCodeIndex], Model.ZipCodeOptions )
}
That produces controls with id like "ZipCodes_1_" and names like "ZipCodes[1]", but does not select the right values. If I explicitly set the Selected property of the right item, then this works:
#for (int zipCodeIndex = 0; zipCodeIndex < Model.ZipCodes.Count; zipCodeIndex++)
{
var zip = Model.ZipCodes[zipCodeIndex];
Html.DropDownListFor( x => x.ZipCodes[zipCodeIndex], Model.ZipCodeOptions.Select( x => (x.Value == zip) ? new SelectListItem() { Value = x.Value, Text = x.Text, Selected = true } : x ) )
}
However, the problem with that approach is that if I add a new drop downs in JavaScript and give them all the name "ZipCodes", then those completely override all the explicitly indexed ones, which never make it to the server. It doesn't seem to like mixing the plain "ZipCodes" name with explicit array elements "ZipCodes[1]", even though they map to the same variable when either is used exclusively.
In the U.I., user's can click a button to add a new drop down and pick another zip code. They're all named ZipCodes, so they all get posted to the ZipCodes array. When rendering the fields in the loop above, I expect it to read the value of the property at the given index, but that doesn't work. I've even tried remapping the SelectListItems so that the proper option's "Selected" property is true, but it still renders the control with nothing selected. What is going wrong?
The reason you first 2 snippets do not work is that ZipCodes is a property in your model, and its the value of your property which determines what is selected (not setting the selected value in the SelectList constructor which is ignored). Since the value of ZipCodes is an array of values, not a single value that matches one of the option values, a match is not found and therefore the first option is selected (because something has to be). Note that internally, the helper method generates a new IEnumerable<SelectListItem> based on the one you provided, and sets the selected attribute based on the model value.
The reason you 3rd and 4th snippets do not work, is due to a known limitation of using the DropDownListFor() method, and to make it work, you need to use an EditorTemplate and pass the SelectList to the template using AdditionalViewData, or construct a new SelectList in each iteration of the loop (as per your last attempt). Note that all it needs to be is
for(int i = 0; i < Model.ZipCodes.Length; i++)
{
#Html.DropDownListFor(m => m.ZipCodes[i],
new SelectList(Model.ZipCodeOptions, "Value", "Text", Model.ZipCodes[i]))
}
If you want to use just a common name (without indexers) for each <select> element using the DropDownList() method, then it needs to be a name which does not match a model property, for example
foreach(var item in Model.ZipCodes)
{
#Html.DropDownList("SelectedZipCodes",
new SelectList(Model.ZipCodeOptions, "Value", "Text", item))
}
and then add an additional parameter string[] SelectedZipCodes in you POST method to bind the values.
Alternatively, use the for loop and DropDownListFor() method as above, but include a hidden input for the indexer which allows non-zero based, non consecutive collection items to be submitted to the controller and modify you script to add new items using the technique shown in this answer
Note an example of using the EditorTemplate with AdditionalViewData is shown in this answer
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 want to have a static list of data in a model that can be used in a viewmodel and dropdown on a view. I want to be able to use it in this way in my controller:
MaintenanceTypeList = new SelectList(g, "MaintenanceTypeID", "MaintenanceTypeName"),
and access it in my view like this:
#Html.LabelFor(model => model.MaintenanceTypeID)
#Html.DropDownListFor(x => x.MaintenanceTypeID, Model.MaintenanceTypeList, "-- Select --", new { style = "width: 150px;" })
#Html.ValidationMessageFor(x => x.MaintenanceTypeID)
I am currently using a repository pattern for data in the database, but don't want to put this data in the database because it will never change. I still want it in a model though. Basically, my dropdown list should offer the following:
Value Text
-------------------------------------
Calibration Calibration
Prevent Preventative Maintenance
CalibrationPrevent PM and Calibration
Any help or examples of static lists using models/oop is appreciated
You can use a list initializer:
public static SomeHelperClass{
public static List<SelectListItem> MaintenanceTypeList {
get {
return new List<SelectListItem>
{ new SelectListItem{Value = "Calibration", Text = "Calibration"}
,new SelectListItem{ Value = "Prevent", Text = "Preventative Maintenance" }
,etc.
};
}
}
}
Hopefully I didn't miss a curly brace somewhere. You can google "C# list initializer" for more examples. I don't remember off top of my head what the actual collection to is for a SelectListCollection is, but I know there is a overload of DropDownList that accepts List as I often just have a collection of keyvaluepairs or something else, and then in my view I convert it to SelectListItems: someList.Select(i => new SelectListItem { Value = i.Key, Text = i.Value })
Note that another option is to place your values in an enum. You can then use a Description attribute on each enum value:
enum MaintenanceType {
[Description("Calibration")]
Calibration = 1,
[Description("Preventative Maintenance")]
Prevent = 2
}
Then you can do things like
Enum.GetValues(typeof(MaintenanceType )).Select(m=>new SelectListItem{ Value = m, Text = m.GetDescription()} ).ToList()
That last line was a little off the top of the head, so hopefully I didn't make a mistake. I feel like an enum is more well structured for what you're trying to do.