I'm using .NET 3.5, MVC.
I want to use a set of string aliases to represent database values. i.e. when a user selects an option from a dropdown it actually sets the value as 0, 1, 2, etc. in the table, rather than the text shown in the dropdown itself.
e.g. I'm doing:
IdName[] Thing = new[] {
new IdName { Id = 0, Name = "No Selection" },
new IdName { Id = 1, Name = "Thing A9" },
new IdName { Id = 2, Name = "Thing C12" },
new IdName { Id = 3, Name = "Thing F4" }
};
MyDropDownList = new SelectList(Things, "Id", "Name",0);
and in the view:
<%= Html.DropDownList("MyDropDownList")%>
Now, this works just fine. What I can't get to work is displaying the value of the field in a 'details' view and showing "Thing C12" as the text instead of "2".
Also, is this the best way to go about this? I don't want to use the actual string in the database in case I modify the text on an entry (e.g. change the name of "Thing F4" to "Thing F5".) I'm totally open to some other ideas.
Thanks!
So you want your action method (that will store the user choice) to store the value rather than the alias shown on the Dropdown.
I think you have two options here.
1- On the server side by getting the value(the id) from your data source, eg: the Things[] array in your example.
public ActionResult StoreValueFromDropDown(string MyDropDownList) {
var id = Things.Single(thing => thing.Name == MyDropDownList).Id;
// here goes the code to sotre the id
}
2- on the client side by adding a hidden field that store the value of the Dropdown.
here is an example using jQuery(I didn't test it):
<input type="hidden" id="ThingId" />
,
$('#MyDropDownList').change(function(e){
$('#ThingId').value($('#MyDropDownList option:selected').attr('value'));
});
then you need to modify your action method to accept the value of that hidden field
public ActionResult StoreValueFromDropDown(int ThingId) {
// here goes the code to sotre the id
}
Related
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.
I have a dynamic list of data with a dynamic number of columns being created by a PIVOT function. Everything more or less works, but I wanted to apply some custom formatting to some of the columns. I figured out how to get a list of the columns by just taking the first row and casting it like so:
var columns = Model.Comparisons.Select(x => x).FirstOrDefault() as IDictionary<string, object>;
Next I decided to create my List by looping over the "columns", which works as long as I reference the dynamic fields in the "format:" clause by their dynamic field name directly for example:
foreach (var c in columns)
{
switch (c.Key)
{
case "Cost":
cols.Add(grid.Column(
columnName: c.Key,
header: c.Key,
format: (item) => Convert.ToDecimal(item.Cost).ToString("C")));
break;
default:
cols.Add(grid.Column(columnName: c.Key, header: c.Key, format: item => item[c.Key]));
break;
}
}
The "default" does not dynamically get the value of each record. I believe it has to do with the "item[c.Key]" vs item.Cost. The problem is I don't want to have to write different case for each field, primarily because I don't know them ahead of time as the data can change. There are about 6 fields that will always be present. I do know however the datatype, which is why I wanted to put a custom format on them.
EDIT
I managed to solve this by writing an extension method.
public static class DynamicDataHelper
{
public static WebGridColumn GetColumn(this HtmlHelper helper, string vendor)
{
return new WebGridColumn()
{
ColumnName = vendor,
Header = vendor,
Format = (item) => helper.ActionLink(
(string)Convert.ToDecimal(item[vendor]).ToString("C"),
"VendorSearch",
"Compare",
new { Vendor = vendor, mpn = item.MPN },
new { target = "_blank" })
};
}
}
I edited my post with the Html Helper that I wrote that will in effect build the custom WebGridColumn objects I was having problems with. The "vendor" is passed in from the View and is then resolved at runtime. It works great.
I am fairly new to SharePoint development and as you may all know that it is very basic for one to know how to access fields in a choice column...
My problem:
I want to access the values of the Check Boxes from a Choice Column.
For Example:
I have a document library called Libe, this document library has a custom column with type Choice and has 4 checkboxes with the values:
Category 1
Category 2
Category 3
Category 4
How do I get the values like literally the text values of what is in the Check Box List: "Category 1", "Category 2" ... "Category 4".
Any ideas?
I can access the column fine and get the selected values, I just do not know how to get the values the user can choose from.
Answer
SPFieldMultiChoice Fld = (SPFieldMultiChoice)list.Fields["Column"];
List<string> fieldList = new List<string>();
foreach (string str in Fld.Choices)
{
fieldList.Add(str);
}
Above is the answer, I can't answer my own question until I have a 100 rep.
using (SPSite site = new SPSite("http://servername/"))
{
using (SPWeb web = site.OpenWeb())
{
SPList list = web.Lists["ListName"];
string values = list["yourColumn"] as string;
string[] choices = null;
if (values != null)
{
choices = values.Split(new string[] { ";#" }, StringSplitOptions.RemoveEmptyEntries);
}
}
}
You can try this code for getting choice field value from document library.
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;
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);
}