ASP. NET web API tutorial (5) data verification

How can I use Web APIs to ensure data validity? In actual projects, no data is submitted to meet the requirements. Besides, there are more than N keywords in tianchao. Therefore, the following content adds web API data verification.
Step 1 modify the Object Model Public Class Userinfo
{
Public Int Id { Get ; Set ;}
[Required]
[Stringlength ( 20 , Errormessage = " The name is too long or too short. " , Minimumlength = 4 )]
Public String Name { Get ;Set ;}

[Regularexpression ( @" ([2-5] \ D) " , Errormessage = " Between 20 and 50 " )]
Public Int Age {Get ; Set ;}
}

Note: You need to add system. componentmodel. dataannotations; reference

Step 2 Add filter

Public Class Validationattribute: actionfilterattribute
{
Public Override Void Onactionexecuting (httpactioncontext actioncontext)
{
If (! Actioncontext. modelstate. isvalid)
{
Actioncontext. Response = actioncontext. Request. createerrorresponse (
Httpstatuscode. badrequest,
Actioncontext. modelstate );
}
}
}

Note: The namespace must be introduced.

Using System. Web;
Using System. Web. http. filters;
Using System. Web. http. modelbinding;
Using System. Web. http. controllers;
Using System. net. HTTP;
Using System. net;
Using Newtonsoft. JSON. LINQ;

 

Step 3 register the filter
Open webapiconfig
AddCode

Config. Filters. Add ( New Filters. validationattribute ());

 

Step 4: Compile the page
Introduce JS/CSS

< Link Href = "Content/site.css" REL = "Stylesheet" Type = "Text/CSS"   />
< Script SRC = "Scripts/jquery-1.7.1.min.js" Type = "Text/JavaScript" > </ Script >
< Script SRC = "Scripts/knockout-2.1.0.js" Type = "Text/JavaScript" > </ Script >
< Script SRC = "Scripts/jquery. Validate. Min. js" Type = "Text/JavaScript" > </ Script >
< Script SRC = "Scripts/jquery. Validate. unobtrusive. Min. js" Type = "Text/JavaScript" > </ Script >

 

Copy htmlpage2 content for slight modification

< Label For = "Text" >
Name </ Label >
< Input ID = "Name" Name = "Name" Data-Val = "True" Data-Val-required = "Did you forget to enter the name? " Type = "Text"
Value = ""   />
< Span Class = "Field-Validation-valid" Data-valmsg- = "Name" Data-valmsg-replace = "True" >
</ Span >
< Label For = "Text" >
Age </ Label >
< Input ID = "Age" Name = "Age" Type = "Text" Data-Val = "True" Data-Val-required = "Age is also required! "
Value = ""   />
< Span Class = "Field-Validation-valid" Data-valmsg- = "Age" Data-valmsg-replace = "True" >
</ Span >
< BR />
< Button Type = "Submit" >
Submit </ Button >

 

Add js to display the error message returned by the Service.

$. Validator. addmethod ("failure", function () {return false ;});
$. Validator. unobtrusive. adapters. addbool ("failure ");
$. Validator. unobtrusive. revalidate = function (Form, validationresult ){
$. Removedata (Form [0], 'validator ');
VaR servervalidationerrors = [];
For (VAR property in validationresult ){
VaR elementid = property. tolowercase ();
Elementid = elementid. substr (elementid. indexof ('.') + 1 );
VaR item = form. Find ('#' + elementid );
Servervalidationerrors. Push (item );
Item. ATTR ('data-Val-failure ', validationresult [property] [0]);
Jquery. validator. unobtrusive. parseelement (item [0]);
}
Form. Valid ();
$. Removedata (Form [0], 'validator ');
$. Each (servervalidationerrors, function (){
This. removeattr ('data-Val-failure ');
Jquery. validator. unobtrusive. parseelement (this [0]);
});
}

 

Added the server error message display operation

400/* badrequest */: function (jqxhr ){
VaR validationresult = $. parsejson (jqxhr. responsetext );
$. Validator. unobtrusive. revalidate (Form, validationresult. modelstate );
}

View test results
1. No input
 

 

2 The input is invalid.

Complete code:/files/risk/web API 5/mvcapplication1.rar