Entity Framework MaxLength Data Annotation

The MaxLength attributes allow you to specify additional property validations. It is applied to a property to specify a maximum number of characters or bytes for the column that the property should map to.

The following example specifies that the Title column in the Books table have a maximum length of 12 characters.

public class Book
{
    public int BookId { get; set; }
    [MaxLength(12)]
    public string Title { get; set; }
}

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If you set a value of Title property greater than the specified length in MaxLength attribute, EF will throw an EntityValidationError.

Validation failed for one or more entities. See 'EntityValidationErrors' property for more details.

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MaxLength attribute can also be used with MinLength attribute.

public class Book
{
    public int BookId { get; set; }
    [MaxLength(12), MinLength(5)]
    public string Title { get; set; }
}

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