In WebAPI, [FromUri] and [FromBody]

vijayaasri palaniappan

Hi,

In WebAPI, I pass the Id as the [FromBody]

{

"Id" : 1

} in JSOn Format.

and Employee as the [FormUri] for the PUT method. It Shows the error:

"Message": "The request is invalid.",
"MessageDetail": "The parameters dictionary contains a null entry for parameter 'id' of non-nullable type 'System.Int32' for method 'System.Net.Http.HttpResponseMessage Put(Int32, EmployeeDataAccess.Employee)' in 'WebAPI.Controllers.EmployeesController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter."

And when I give ID as the [FromUri] and Employee as the [FormBody]. It Updated Successfully.Pls share Your Idea.

Thanks in Advance.

4 Replies

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vijayaasri palaniappan5y ago
Yeah,

         public HttpResponseMessage Put( [FromBody]int id, [FromUri] Employee employee)
         {
            try
            {
Sachin Singh5y ago
is it like this
Put([FromBody]Int Id,[FromUri] EmployeeDataAccess.Employee emp)
{
//

}
if yes then it should work, send Employee properties like name, salary in URL as query string and Id from Body and it should work.
vijayaasri palaniappan5y ago
Hi Sachin,

I Refer Your article I have decorated id parameter with [FromBody] attribute, this forces Web API to get it from the request body. My code is also like Yours. Then Why I get this error.
Sachin Singh5y ago
yes, because you forget the simple thing, that is parameter binding.

Web API has its own rule to bind parameters, which can be understood as following.

Web API uses default convention for binding parameters.
1. If a parameter is a primitive type like int, bool, double, etc, web API tries to get the value from the URI(either from the Routed data or query string).
2. If the parameter is a complex type like Employee, Customer, etc then web API tries to get the value from the request body.

if you want to understand it in deep then go through my article on this

https://www.sharpencode.com/article/WebApi/parameter-binding