asp.net MVC的验证注解对美元汇率 [英] asp.net mvc validation annotation for dollar currency

问题描述

我为 Html.TextBoxFor 验证。这里是我的code ...查看

I am validation for Html.TextBoxFor. Here is my code on the view

@Html.TextBoxFor(m => m.Amount, new {@class = "form-control", Value = String.Format("{0:C}", Model.Amount) })

这code需要从数据库5000.00一样，并显示在用户界面上的双重价值为$ 5,000.00。然而，当用户点击提交按钮，将显示一个验证错误

This code takes the double value from the database like 5000.00 and displays on the UI as $5,000.00. However when the user hits the submit button, a validation error is displayed that

值'$ 5,000.00'是无效的金额。

The value '$5,000.00' is not valid for Amount.

在模型验证我的注解是

[Range(0, double.MaxValue, ErrorMessage = "Please enter valid dollar amount")]

要得到它提交，我不得不重新输入为5000.00。我该如何解决这个问题？谢谢你。

To get it to submit, I had to retype as 5000.00. How can I fix this? Thanks.

推荐答案

当你做值=的String.Format（{0：C}，Model.Amount）在htmlAttributes，剃刀将执行C＃code和返回值，$ 125.67，（假设你的金额属性是 125.67M ），这是一个字符串。因此，通过您的视图生成的标记为

When you do the value = string.Format("{0:C}", Model.Amount) in the htmlAttributes, razor will execute the C# code and return the value,"$125.67", (Assuming the value of your Amount property is 125.67M) which is a string. So the markup generated by your view will be

<input value="$125.67" class="form-control" id="Amount" name="Amount" type="text">

现在因为 $ 125.67 不是不是的Valide十进制值，而是一个字符串。它不能映射该文本框的金额您的视图模型的财产类型为十进制/ doube的价值。

Now since $125.67 is not not a valide decimal value, but a string. it cannot map the value of this textbox to the Amount property of your view model which is of type decimal/doube.

您可以做的是，在字符串类型的您的视图模型存储此格式的字符串值，当用户提交表单，尝试解析回小数变量并使用它创建一个新的属性。

What you can do is, create a new property in your view model of type string to store this formatted string value and when user submits the form, try to parse it back to a decimal variable and use it.

因此​​，一个新的属性添加到您的视图模型

So add a new property to your view model

public class CreateOrderVm
{
  public int Id { set;get;}
  public string AmountFormatted { set;get;}  // New property
  public decimal Amount  { set;get;}
}

和在你看来，这是强类型为CreateOrderVm

And in your view, which is strongly typed to CreateOrderVm

@model CreateOrderVm
@using(Html.BeginForm())
{
    @Html.TextBoxFor(m => m.AmountFormatted, new { @class = "form-control",
                                Value = String.Format("{0:C}", Model.Amount) })

    <input type="submit" />
}

而在你的HttpPost行动

And in your HttpPost action

[HttpPost]
public ActionResult Create(CreateOrderVm model)
{
    decimal amountVal;

    if (Decimal.TryParse(vm.AmountFormatted, NumberStyles.Currency,
                                             CultureInfo.CurrentCulture, out amountVal))
    {
        vm.Amount = amountVal;
    }
    else
    {
       //add a Model state error and return the model to view,
    }

    //vm.Amount has the correct decimal value now. Use it to save
    // to do  :Return something
}

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