问题
In an ASP.NET Core 2.0 application, I have a Foo
class with a lot of classical string or numeric members and also a int? Budget
field.
using Microsoft.AspNetCore.Http;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
namespace MyProj.ViewModels {
public class RecordEditViewModel {
public RecordEditViewModel() { }
public string Name { get; set; }
public string Prop1 { get; set; }
public string Prop2 { get; set; }
public string Prop3 { get; set; }
public string Prop4 { get; set; }
public string Prop5 { get; set; }
/// <summary>The project budget</summary>
//[Range(0, int.MaxValue, ErrorMessage = "Must be a positive number")]
[Display(Name = "Budget REVM"),
DataType(DataType.Currency),
DisplayFormat(NullDisplayText = "-",
ApplyFormatInEditMode = true,
DataFormatString = "{0:C}")]
public int? Budget { get; set; }
public string Prop6 { get; set; }
public string Prop7 { get; set; }
public string Prop8 { get; set; }
public DateTime CreatedOn { get; set; }
public string Prop9 { get; set; }
public string Prop10 { get; set; }
public string Prop11 { get; set; }
[Display(Name = "Attachments"), UIHint("IFromFile")]
public IEnumerable<IFormFile> Attachments { get; set; }
public string Id { get; set; }
}
}
I want to
a) display it in the 14 000 €
format
b) edit it in the 14 000 €
format
this is a classic behavior, display/edit a currency in the currency format, but is seems hard to implement in the latest Microsoft .NET Framework.
a) CustomModelBinder
? Should rewrite a binder for all the rest of the fields, but I need only the Budget
b) TypeConverter
?
c) DataType(DataType.Currency)
? does not seem to work in edit mode (not in display for int?)
My view:
<div class="col-md-6">
<label asp-for="Budget" class="control-label"></label>
<div>
<input asp-for="Budget" class="form-control" />
<span asp-validation-for="Budget" class="text-danger"></span>
</div>
</div>
回答1:
I noticed that InputTagHelper has a Format property, which means one can write :
<input asp-for="Budget" asp-format="{0:C}" class="form-control" />
Finding that though was not easy. It wasn't mentioned in the Input Tag Helper section of the intro. In the end I found it through ASP.NET Core MVC Input Tag Helper Deep Dive
Now I understand why people say ASP.NET Core's documentation is lacking - the intro goes to great lenghts to explain the various tag helpers in a single article, explains their relation to HTML Helpers, but ommits significant properties like Format
. Without direct link to the class's documentation, it takes a bit of digging to find it.
There are quite a few similar questions in SO with answers that say "you can't format" or propose custom solutions.
UPDATE
An issue was opened on July 2017 about POSTing currency values that included a currency symbol. The thread is insteresting as it explains that asp-format
only affects display, so the recommended solution is to put the symbol outside the input
, possibly using Bootstrap input groups :
The recommended solution here is to place the currency indicator outside of the editable field (e.g. before or after)
Perhaps something like this:
<div class="input-group">
<input asp-for="Budget" asp-format="{0:#,###.00}" class="form-control" />
<span class="input-group-addon">€</span>
</div>
回答2:
My biggest finding was to ensure you are not just rendering the field via your own tag within the .cshtml; rather, ensure you are using the @Html.EditorFor() syntax to render the field:
<div class="col-md-10">
@Html.EditorFor(model => Model.AmountPaid)
<span asp-validation-for="AmountPaid" class="text-danger" />
</div>
Once I used this, the validation worked correctly. You can also decorate your field, such as:
[DataType(DataType.Currency)]
[Column(TypeName = "decimal(18, 2)")]
public decimal AmountPaid { get; set; }
https://docs.microsoft.com/en-us/aspnet/core/tutorials/razor-pages/validation?view=aspnetcore-2.2
来源:https://stackoverflow.com/questions/48205531/display-edit-a-currency-in-asp-net-mvc-core-why-so-complicated