How to get the validation error list of tryvalidatemodel in MVC?

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I have a method that accepts an Id parameter. I get the record from Database using that parameter and I have made some changes to the record.

Now, I want to validate those changes using "TryValidateModel" or "ValidateModel" and I want to get the list of errors if there is any to send them through API and not sending them to view.

I have been searching for a way to do that and most of the articles that I found are talking about getting them through "ModelState.Where". However, the record is not coming from a view.

Here is the method:

What I have tried:

public async Task<ActionResult> Anyname(int id)
        {
            // Get record
            var app = await db.Appointments.FindAsync(id);
            // Do some changes
            app.patFname = null;
            //..
            //..
            // check if model is valid
            bool isValid = TryValidateModel(app);
            if (!isValid)
            {
                // I want to get the list of error and send them back 
            }
            else
            {
                return new HttpStatusCodeResult(200);
            }
        }

Posted 21-Jul-20 0:19am

Member 12701700

Updated 28-Mar-21 22:54pm

v2

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3 solutions

Solution 1

Seems straight forward with passing the model instance to the TryValidateModel.
Just pass the instance of your model to check, something like below:

C#

UserInfo info = new UserInfo();
info.FirstName = "value from DB";
info.LastName = "known value";
info.BirthDate = DateTime.Parse("user provided value");

if(TryValidateModel(info))
{
       //Valid
       
}
else
{
       //InValid
}

Refer: Validate Model Programmatically in ASP.NET MVC | BinaryIntellect Knowledge Base[^]

Posted 21-Jul-20 0:54am

Sandeep Mewara

Comments

Member 12701700 22-Jul-20 7:43am

Naah, I was trying to grab the list of errors.
I know that TryValidateModel will check if it's valid or not,
I just want to get the error list if not valid.
I hope that makes it clear.
Thanks antway

Sandeep Mewara 22-Jul-20 8:19am

You ned to use: ValidateSummary for it. Examples on web. see: https://www.tutorialsteacher.com/mvc/htmlhelper-validationsummary

Member 12701700 22-Jul-20 9:32am

No man, I am trying to get the list of errors in the controller not in the view,
I want to send them through API.
Got me :) thanks in advance

Solution 2

var errors = ModelState.Select(x => x.Value.Errors)
                           .Where(y=>y.Count>0)
                           .ToList();

Posted 2-Mar-21 4:23am

Member 13820968

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Booki77 · Accepted Answer · 2021-03-28T22:54:00

have a look to the sources:
GitHub MVC Controller

after calling TryValidationModel - you can get the errors via ModelState.
have a look to function below.

am sure you can modify that code for you specific needs.

protected internal bool TryValidateModel(object model, string prefix)
{
    if (model == null)
    {
        throw new ArgumentNullException("model");
    }

    ModelMetadata metadata = ModelMetadataProviders.Current.GetMetadataForType(() => model, model.GetType());

    foreach (ModelValidationResult validationResult in ModelValidator.GetModelValidator(metadata, ControllerContext).Validate(null))
    {
        ModelState.AddModelError(DefaultModelBinder.CreateSubPropertyName(prefix, validationResult.MemberName), validationResult.Message);
    }

    return ModelState.IsValid;
}