Summary of problems in calling web Api methods using ajax, ajaxapi

Summary of problems in calling web Api methods using ajax, ajaxapi

1. Get request

1. There is no parameter Get request, which is the same as ajax requests.

$. Ajax ({
Url: '.../api/User/UserVerify,
Type: 'get ',
Success: function (json ){
Alert (json );
},
Error: function (){
Alert ("error ");
}
});

In this case, the api code of the background code can be directly public string UserVerify () {}, and the HttpGet feature must be added to the action.

2. Get requests with one or more parameters

$. Ajax ({
Url: '.../api/User/UserVerify? LoginName = admin & passWord = 123456 ',
Type: 'get ',
Success: function (json ){
Alert (json );
},
Error: function (){
Alert ("erroe ");
}
});

In this case, the background Api code can be public string LoginVerify (string loginName, string passWord) {}. you need to add the HttpGet feature to the action.

Ii. Post requests

1. Post requests without Parameters

$. Post (
'.../Api/User/UserVerify ',
Function (json ){
Alert (json );
});

In this case, the backend call needs to add the HttpPost feature on the Action, public string LoginVerify (){}

2. A parameter Post request

In a post request, the parameter of a method must be modified using the [FromBody] attribute. The [FromBody] tells the Web API to retrieve the parameter value from the post request weight. That is, it should be written as follows:

[HttpPost, ActionName ("UserVerify")]
Public string LoginVerify ([FromBody] string loginName ){}

At the same time, if the front-end call is still in the previous format

$. Post (
'.../Api/User/UserVerify ',
{LoginName: "admin "},
Function (json ){
Alert (json );
});

The following situation occurs: The jump can be normal, but the corresponding transmitted value cannot be obtained. Because the Web API requires the [FromBody] parameter to be passed by the request, it must have a specific format before it can be obtained correctly. This specific format is not common key = value pairs. The Web API Model binder wants to find the value without a key name in [FromBody], that is, it is not key = value, but = value.

Therefore, we will modify the call parameters to the following form:

Note that the service must be regenerated at this time.

3. Post requests with two or more parameters

[FromBody] only one modified parameter can be. We need to encapsulate multiple parameters passed.

Here, we can encapsulate loginName and passWord into a User class.

 

Background method required

[HttpPost, ActionName ("UserVerify")]
Public string LoginVerify ([FromBody] UserExEntity user)
{
Try
{
Return "name" + user. loginName + "passWord" + user. passWord;
}
Catch
{
Return null;
}
}

 

Frontend call required

At this point, we can see that the Form Data format is key = value & key = value. We usually use a lot of json format.