Bind query parameters to a model in ASP.NET Core

Question

I am trying to use model binding from query parameters to an object for searching.

My search object is

[DataContract]
public class Criteria 
{
  [DataMember(Name = "first_name")]
  public string FirstName { get; set; }
}

My controller has the following action

[Route("users")]
public class UserController : Controller 
{
  [HttpGet("search")]
  public IActionResult Search([FromQuery] Criteria criteria)
  {
    ...
  }
}

When I call the endpoint as follows .../users/search?first_name=dave the criteria property on the controller action is null. However, I can call the endpoint not as snake case .../users/search?firstName=dave and the criteria property contains the property value. In this case Model Binding has worked but not when I use snake_case.

How can I use snake_case with Model Binding?

Solution 1

You need to add [FromQuery] attribute to the model properties individually

public class Criteria
{
  [FromQuery(Name = "first_name")]
  public string FirstName { get; set; }
}

Solution 2

Solution for .net core 2.1, 2.2, 3.0 and 3.1

Or without attributes you can do something like this which is cleaner I think (of course if the model properties are same as query parameters).

Meanwhile I use it in .net core 2.1, 2.2 and 3.0 preview & 3.1.

public async Task<IActionResult> Get([FromQuery]ReportQueryModel queryModel) 
{ 

}

Solution 3

For anyone that got here from search engine like me:

To make it work on asp.net core 3.1+

public async Task<IActionResult> Get([FromQuery] RequestDto request);

public class RequestDto
{
  [FromQuery(Name = "otherName")]
  public string Name { get; set; }
}

Will read json property otherName into RequestDto.Name so basically you have to use FromQuery in 2 places. Above answers are IMHO too complicated for such a simple thing already provided in asp.net framework.

Solution 4

In my case, I had an issue where my parameter name was option and in my class I also had the property called option so it was collapsing.

public class Content
{
    
    public string Option { get; set; }
    
    public int Page { get; set; }
}

public async Task<IActionResult> SendContent([FromQuery] Content option)

changed the parameter to something else:

public async Task<IActionResult> SendContent([FromQuery] Content contentOptions)

View more solutions

Comments

[Dmitry Pavlov]

What if I want to use data contracts with members with the custom names for GET and POST endpoints, so in the first case it will be FromQuery, and FromBody for POST request?

[sander]

I can't get this to work but it is marked as an answer.

[sander]

I just want to add that I had an issue which other people could encounter too: I named my parameter 'model'. My object had a property which was also named 'model'. The databinding wouldn't work untill I renamed my parameter.

[Alexandre Ribeiro]

Yep, it works only with [FromQuery] in controller method

[Daniel Gimenez]

This is the correct answer for NetCore 2.1 and above, the accepted answer is an anachronism.

[Mohsen Kamrani]

Either this should be the accepted answer or the OP which happens to be the one who's given the accepted answer should update their answer.

[Rebecca]

I think the problem is that this answer doesn't address the specifics of question. The OP specifically requires a different name for the property, and this doesn't support that, as stated by the person that gave this answer.

[Ramūnas]

FromQuery sits in Microsoft.AspNetCore.Mvc package, it is a bit sad to add this dependency to the project where you only store your POCO.

[Twisted Whisper]

I'm using .net core 2.2 and this method doesn't work for me. However, the accepted answer does.

[peyman gilmour]

@TwistedWhisper I am still using it! Can be related to the binding. Are you sure you have same parameters in both side ( query string and class object ) ?

[peyman gilmour]

@TwistedWhisper It works fine for me. I am using it in .net core 2.2 and 3.0 preview 5 and 6. The secret is you have to have same spelling properties in both sides.

[Alex Gamezo]

Make sure you're using Properties, in the Request model, and not fields. That was my missed mistake

[elembie]

@sander 's solution worked for me - thank you I spend well over an hour trying to figure this one out. Lesson learned to check all parameter names.

[sander]

@elembie yeah, this one was a real gotcha!

[Max]

It will also works with [JsonPropertyName("otherName")] on your properties. Because of that I´m assuming it will also work with Newtonsoft.JSON annotations (but didn´t try). So you can just specify [FromQuery] in your method and could still use the same object in a Body when needed (without additional annotations). No need to be this specific about it.

[peyman gilmour]

@TwistedWhisper That's true. Same spelling!

[peyman gilmour]

@AlexGamezo That's true. It is important to use properties.

[Sudara]

Yes, those should be properties with getter and setter and the class should have a parameterless constructor too

[code5]

@Max - hi Max. No it doesn't work for Newtonsoft [JsonPropery(Name = "otherName")]