Check specific field is valid .NET

Question

I want to check for specific field is valid in my .NET Core MVC Project. I know there is the ModelState.IsValid method which check the entire Model, but i need to check only one property in the model.

below is my Model:

public class MyModel
{
	[Required(AllowEmptyStrings = false)]
	[StringLength(10)]
	[RegularExpression(@"^[0-9]*$", ErrorMessage = "Invalid ID")]
	[Display(Name = "IdentityNo")]

	[Required(AllowEmptyStrings = false)]
	[StringLength(256)]
	[RegularExpression(@"^[A-Za-z0-9\s!@#$%^&*()_+=-`~\\\]\[{}|';:/.,?]*$", ErrorMessage ="Invalid Email or username")]
	public string UserNameOrEmailAddress { get; set; }

	[Required(AllowEmptyStrings = false)]
	[StringLength(50)]
	[DataType(DataType.Password)]
	public string Password { get; set; }

}

 

If i use ModelState.IsValid will check all the model, and i want to check only ID property. below is how i check the validation in the Controller:

if (ModelState.IsValid)
{
    // code
}

it's will return false, because i only entry ID, username and password leve it empty.

How to check specific property in my Model?

Answer 1

How to check specific field in .NET MVC

You can check one field in your model, like the example we will check only the ID property using ModelState["FieldName"] Instead of ModelState.IsValid

Like this:

 if(ModelState["ID"].Errors.Count > 0)
{
    foreach(var error in ModelState["ID"].Errors)
    {
        ModelState.AddModelError("", error.ErrorMessage);
        return View();
    }
}
// code