Skip to content
: Validates that the property has a credit card format. Requires.: Validates that the field isn't null. Seefor details about this attribute's behavior.: Validates input on the client by calling an action method on the server. Seefor details about this attribute's behavior.
Datavalidering
Backend Dag 6 Agila Projekt, Datavalidering & CORS.pdf
2.3 MB
Det räcker att ni har koll på:
Required
Email Adress
Range
StringLength
Validation attributes
Validation attributes let you specify validation rules for model properties. The following example from the shows a model class that is annotated with validation attributes. The [ClassicMovie] attribute is a custom validation attribute and the others are built in. Not shown is [ClassicMovieWithClientValidator], which shows an alternative way to implement a custom attribute.
C#Copy
Movie
{
; }
]
]
!;
]
]
]
; }
]
]
!;
]
; }
; }
; }
}
Built-in attributes
Here are some of the built-in validation attributes:
A complete list of validation attributes can be found in the namespace.
Error messages
Validation attributes let you specify the error message to be displayed for invalid input. For example:
C#Copy
]
Internally, the attributes call with a placeholder for the field name and sometimes additional placeholders. For example:
C#Copy
]
When applied to a Name property, the error message created by the preceding code would be "Name length must be between 6 and 8.".
To find out which parameters are passed to String.Format for a particular attribute's error message, see the .
Non-nullable reference types and the [Required] attribute
The validation system treats non-nullable parameters or bound properties as if they had a [Required(AllowEmptyStrings = true)] attribute. By , MVC implicitly starts validating non-nullable properties or parameters as if they had been attributed with the [Required(AllowEmptyStrings = true)] attribute. Consider the following code:
C#Copy
Person
{
; }
}
If the app was built with <Nullable>enable</Nullable>, a missing value for Name in a JSON or form post results in a validation error. Use a nullable reference type to allow null or missing values to be specified for the Name property:
C#Copy
Person
{
; }
}
This behavior can be disabled by configuring in Program.cs:
C#Copy
builder.Services.AddControllers(
);
Non-nullable properties on generic types and [Required] attribute
Non-nullable properties on generic types must include the [Required] attribute when the type is required. In the following code, TestRequired is not required:
C#Copy
>
{
public string TestRequired { get; set; } = null!;
; }
}
In the following code, TestRequired is explicitly marked as required:
C#Copy
System.ComponentModel.DataAnnotations;
>
{
[Required] public string TestRequired { get; set; } = null!;
; }
Want to print your doc?
This is not the way.
This is not the way.
Try clicking the ··· in the right corner or using a keyboard shortcut (
CtrlP
) instead.