Detailed description of ASP. net mvc 2 custom Verification

BKJIA exclusive Article] ASP. net mvc 2 has built-in support for verifying data annotation verification properties on the server. This article describes how to use System. componentModel. the basic class in DataAnnotations builds custom validation attributes, about ASP. net mvc 2 Data annotation is how to work, please refer to Brad's blog http://bradwilson.typepad.com/blog/2009/04/dataannotations-and-aspnet-mvc.html ).

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I will introduce how to connect to the client verification extension of ASP. NET MVC 2 so that you can run JavaScript verification logic on the client.

I will create a PriceAttribute to verify whether a value is greater than the specified price and the price must end at 99, so $20.00 is invalid and $19.99 is valid. The code for this attribute is as follows:

 
 

  
  
public class PriceAttribute : ValidationAttribute {  
  
  
  public double MinPrice { get; set; }  
  
  
      
  
  
  public override bool IsValid(object value) {  
  
  
    if (value == null) {  
  
  
      return true;  
  
  
    }  
  
  
    var price = (double)value;  
  
  
    if (price < MinPrice) {  
  
  
      return false;  
  
  
    }  
  
  
    double cents = price - Math.Truncate(price);  
  
  
    if(cents < 0.99 || cents >= 0.995) {  
  
  
      return false;  
  
  
    }  
  
  
         
  
  
    return true;  
  
  
  }  
  
  
} 
 
 

Note: If the value is null, the returned value is true. This attribute does not verify whether the field is required. I will verify whether the value is required in RequiredAttribute. It allows me to place attributes on optional values. An error is displayed when you leave this field blank.

We can create a view model and apply this attribute to the model for rapid testing. The code for this model is as follows:

 
 

  
  
public class ProductViewModel {  
  
  
  [Price(MinPrice = 1.99)]  
  
  
  public double Price { get; set; }  
  
  
 
  
  
  [Required]  
  
  
  public string Title { get; set; }  
  
  
} 
 
 

Create a View Index. aspx) to display and edit the form:

 
 

  
  
<%@ Page Language="C#" Inherits="ViewPage  "  %> 
  
  
 
  
  
<% using (Html.BeginForm()) { %> 
  
  
 
  
  
  <%= Html.TextBoxFor(m => m.Title) %> 
  
  
    <%= Html.ValidationMessageFor(m => m.Title) %> 
  
  
  <%= Html.TextBoxFor(m => m.Price) %> 
  
  
    <%= Html.ValidationMessageFor(m => m.Price) %> 
  
  
      
  
  
    <input type="submit" /> 
  
  
<% } %> 
 
 

Now we only need one controller with two actions, one editing view, and the other receiving the submitted ProductViewModel.

 
 

  
  
[HandleError]  
  
  
public class HomeController : Controller {  
  
  
  public ActionResult Index() {  
  
  
    return View(new ProductViewModel());  
  
  
  }  
  
  
 
  
  
  [HttpPost]  
  
  
  public ActionResult Index(ProductViewModel model) {  
  
  
    return View(model);  
  
  
  }  
  
  
} 
 
 

We have not enabled client verification. Next let's see what happens when we view this page and submit some values.