How to pass multiple model as parameter in WEB API

Nikunj Satasiya

5y8.8k.NET

Can anyone please help me to pass multiple models as a parameter to the request's content in WEB API?

I have 2 different Model Student and Employee

public class Student
{
public int StudentId { get; set; }
public string StudentName { get; set; }
public string Branch { get; set; }
}
public class Employee
{
public int EmployeeId { get; set; }
public string EmployeeName { get; set; }
public string Department { get; set; }
}

I have created an API and want to pass both these models as parameters in my action method InsertTestAPI.

[HttpPost]
[Route("TestAPI")]
public HttpResponseMessage InsertTestAPI(Student modelStudent, Employee modelEmployee)
{
// other logical operations
}

When I pass these models as JSON in the request body, I get the following error in Postman.

{
"$id": "1",
"Message": "An error has occurred.",
"ExceptionMessage": "Can't bind multiple parameters ('modelStudent' and 'modelEmployee') to the request's content.",
"ExceptionType": "System.InvalidOperationException",
"StackTrace": " at System.Web.Http.Controllers.HttpActionBinding.ExecuteBindingAsync(HttpActionContext actionContext, CancellationToken cancellationToken)\r\n at System.Web.Http.Controllers.ActionFilterResult.d__5.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Dispatcher.HttpControllerDispatcher.d__15.MoveNext()"
}

Can anyone please help me?

5 Replies

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Kiran Mohanty5y ago
Accepted answer
POST requests accept only 1 parameter as it reads data from request body.
Solutions that you may wish to go for:-
1. Wrap both objects in another class and expect only instance of new object type.
2. pass one object as query string and expect another from request body( as action parameter )
Ex- api/controller/action?emp = stringifiedJson and pass student as you are passing for post request.
3. change action type to get.
swapna5y ago
viewmodel
Kiran Mohanty5y ago
HI,
I was talking about 3 different approaches . Either approach 1 or 2 or 3. All 3 are not together as one solution :) .
Asma Khalid5y ago
First change the method defination as follow i.e.
[HttpPost]
[Route("TestAPI")]

public HttpResponseMessage InsertTestAPI([FromBody]JToken postData)
{
    // other logical operations
}
Then create one JSON object mapper i.e.
public class ApiData
    {
        public Student StudentObj { get; set; }
        public Employee EmployeeObj { get; set; }
    }
Assign your target objects to the ApiData class i.e.
ApiData myData = new ApiData();

myData.StudentObj = modelStudent;
myData.EmployeeObj = modelEmployee;
Finally convert your 'myData' object to JSON format and pass that to your Web API. To know more about RESTful Web API Post method Development do look into https://bit.ly/2sONwnw
Mark answer as accpted if helpful

Thanks & Regards,
Asma Khalid

For More Visit: www.asmak9.com or www.bytezaar.com
Nikunj Satasiya5y ago
Thank you, Kiran for your valuable answer, I got a solution and it works.

I have created another class and merged both models into a single unit called StudentEmployeModel
public class StudentEmployeModel
{
public Student Students{get;set;}
public Employee Employees{get;set;}
}
Then, I used this in my action method as a parameter, Actually no need to change the action type to get from the post.
[HttpPost]
[Route("TestAPI")]

public HttpResponseMessage InsertTestAPI(StudentEmployeModel model)
{
    // other logical operations
}
Finally, pass input parameter as JSON in request body.
{ "students":
    { "studentId":"1", "studentName":"Nikunj Satasiya", "branch":"computer engineering" } ,
"employees":
    {"employeeId ":1,"employeeName":"Nikunj Satasiya","department":"IT"}
}
Finally, it works.
Thank you.