MaxLength and MinLength Validator in ASP.NET MVC tutorial with examples

MaxLength and MinLength Validator in ASP.NET MVC: A Tutorial with Code Examples. When building web applications, it's important to validate user input to ensure that the data entered into the system is accurate and conforms to specific standards. In ASP.NET MVC, data annotations provide an easy way to specify validation rules for model properties. In this post, we'll take a look at two of these annotations: MaxLength and MinLength.

MaxLength and MinLength are data annotations that are used to set the maximum and minimum length of a string property in a model. They are used to restrict the length of user input and ensure that the data entered into the system meets the specified criteria.

Here's an example of a model that uses MaxLength and MinLength annotations:

public class Person
{
    [MinLength(3)]
    [MaxLength(50)]
    public string Name { get; set; }
}

In this example, the Name property has a MinLength of 3 and a MaxLength of 50. This means that the Name property must have a minimum length of 3 characters and a maximum length of 50 characters.

When a user submits a form, the model binder will automatically validate the user input against the specified MinLength and MaxLength constraints. If the user input does not meet these constraints, the model binder will return an error and the user will need to enter a valid value.

Here's an example of a view that displays a form for entering the Name property:

@model Person

    

        Name:
         @Html.TextBoxFor(x => x.Name, new { @class = "form-control" })
        @Html.ValidationMessageFor(model => model.Name)
    
    

In this view, the Html.ValidationMessageFor method is used to display validation errors for the Name property. If the user input does not meet the specified MinLength and MaxLength constraints, an error message will be displayed next to the input field.

In conclusion, MaxLength and MinLength annotations are a simple and effective way to validate user input in ASP.NET MVC. By using these annotations, you can ensure that the data entered into your application meets specific standards and constraints.