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?

Possible duplicate of Model binding in ASP.NET Core to map underscores to title case property names — Win
– Win, Commented Mar 21, 2017 at 15:43

Carl Thomas · Accepted Answer · 2017-03-21 14:11:49Z

82

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

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

answered Mar 21, 2017 at 14:11

Carl Thomas

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6 Comments

Dmitry Pavlov Over a year ago

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 Over a year ago

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

sander Over a year ago

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.

Ramūnas Over a year ago

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.

elembie Over a year ago

@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.

|

peyman gilmour · Accepted Answer · 2020-03-27 16:28:56Z

46

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) 
{ 

}

edited Mar 27, 2020 at 16:28

answered Jul 12, 2018 at 12:18

peyman gilmour

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11 Comments

Daniel Gimenez Over a year ago

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

Mohsen Kamrani Over a year ago

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 Over a year ago

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.

Twisted Whisper Over a year ago

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

Alex Gamezo Over a year ago

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

|

n.podbielski · Accepted Answer · 2020-07-31 09:35:06Z

14

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.

answered Jul 31, 2020 at 9:35

n.podbielski

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2 Comments

Max Over a year ago

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.

code5 Over a year ago

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

Giga Meta · Accepted Answer · 2021-09-20 12:22:35Z

3

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)

edited Sep 20, 2021 at 12:22

answered Sep 14, 2021 at 20:35

Giga Meta

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1 Comment

Tomasz Juszczak Over a year ago

Thats the correct answer that should be accepted here, the [FromQuery] looks for a name, if the name is duplicated from an actual object it will assume you want to use , separator instead of named separator from query. So I add optionQuery as a name instead of just options

Emery Noel · Accepted Answer · 2023-08-09 13:13:07Z

2

In .NET 6, I needed to add [FromQuery] to the endpoint's parameter, as well as add [FromQuery(Name="")] to each of the model's properties.

Rather than add the MVC dependency to my model project, I turned the service model into an interface and made a new model in the WebAPI project, which can use the annotations and implement the interface, so I don't need to create/map 2 models.

answered Aug 9, 2023 at 13:13

Emery Noel

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Comments

th3morg · Accepted Answer · 2019-12-05 21:33:21Z

1

According to @Carl Thomas answer, here is the easier and the strongly typed way to have snake case FromQuery name:

CustomFromQuery

public class CustomFromQueryAttribute : FromQueryAttribute
{
    public CustomFromQuery(string name)
    {
        Name = name.ToSnakeCase();
    }
}

StringExtensions

public static class ObjectExtensions
{
  public static string ToSnakeCase(this string o) => Regex.Replace(o, @"(\w)([A-Z])", "$1_$2").ToLower();
}

Usage

public class Criteria
{
   [CustomFromQuery(nameof(FirstName))]
   public string FirstName { get; set; }
}

edited Dec 5, 2019 at 21:33

th3morg

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answered Jul 4, 2019 at 10:10

Soheil Alizadeh

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Comments

Post Impatica · Accepted Answer · 2024-01-19 15:05:24Z

1

I don't know what is going on in .NET 8 or if it is just my setup but I can't get [FromQuery] to work like @emery-noel said in his answer or any other answer for that matter.

Example, this will not work:

[HttpGet]
public async Task<IActionResult> Agreements([FromQuery] ClientDocumentsParamsDTO parameters) { ...etc... }

[AsParameters] doesn't work either. My only option is to either do something ugly like this:

[HttpGet]
public async Task<IActionResult> Agreements(
    [FromQuery(Name = "organizationid")] int OrganizationId,
    [FromQuery(Name = "account-class-id")] int? AccountClassId,
    [FromQuery(Name = "account-preference-id")] int? AccountPreferenceId,
    [FromQuery(Name = "account-category-id")] int? AccountCategoryId,
    [FromQuery(Name = "account-type-id")] int? AccountTypeId
    )
{ 
 ... etc...

or something like this I'm guessing, which I haven't tried:

[HttpGet]
public async Task<IActionResult> Agreements(){
  string fullname1 = Request.QueryString["fullname"];
}

I'm guessing it has something to do with THIS issue but I don't know.

edited Jan 19, 2024 at 15:05

answered Jan 10, 2024 at 21:05

Post Impatica

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1 Comment

Andreas Griechihin Over a year ago

I also was not able to get it to work in .NET 8 for a while, finally come up with this approach: stackoverflow.com/a/78970956/12888162

Andreas Griechihin · Accepted Answer · 2024-09-10 18:59:47Z

I found one solution to get it to work and do not look too ugly:

public static async Task<IResult> GetAttachments([AsParameters] PagedRequest request, IAttachmentService service)
{
    try
    {
        var attachments = await service.GetAttachmentsAsync(request);

        return TypedResults.Ok(attachments);
    }
    catch (Exception ex)
    {
        return Results.Problem(ex.Message);
    }
}

My PagedRequest looks like this:

public sealed class PagedRequest
{
    [FromQuery(Name = "page")]
    public int Page { get; set; } = 1;

    [FromQuery(Name = "pageSize")]
    public int PageSize { get; set; } = 10;

    [FromQuery(Name = "search")]
    public string? Search { get; set; }

    [FromQuery(Name = "searchBy")]
    public string? SearchBy { get; set; }

    [FromQuery(Name = "sortBy")]
    public string? SortBy { get; set; }

    [FromQuery(Name = "sortDirection")]
    public string? SortDirection { get; set; }
}

Endpoint will look like this:

Florian Hilfenhaus · Accepted Answer · 2021-01-04 20:29:06Z

0

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

not work for anyone, you can try [FromRoute]

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

In your dto you must keep the [FromQuery]

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

edited Jan 4, 2021 at 20:29

answered Jan 4, 2021 at 20:22

Florian Hilfenhaus

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