How to deal with user input validation issues in C# development

How to handle the verification of user input in C# development requires specific code examples

Introduction:
In C# development, how to handle the verification of user input is Very important part. The verification of user input can not only ensure the security of the system, but also improve the stability and user experience of the system. This article will introduce how to handle user input validation in C# development and provide specific code examples.

1. Use regular expressions to verify user input
Regular expression is a powerful string matching tool that can be used to verify whether the format of user input is correct. The following is an example that demonstrates how to use regular expressions to verify the email entered by the user:

using System;
using System.Text.RegularExpressions;

class Program
{
    static void Main()
    {
        string email = GetEmail();

        bool isValidEmail = IsValidEmail(email);

        if (isValidEmail)
        {
            Console.WriteLine("邮箱输入正确");
        }
        else
        {
            Console.WriteLine("邮箱输入有误");
        }

        Console.ReadKey();
    }

    static string GetEmail()
    {
        Console.WriteLine("请输入您的邮箱：");
        return Console.ReadLine();
    }

    static bool IsValidEmail(string email)
    {
        string pattern = @"^[w.-]+@[w.-]+.w+$";
        return Regex.IsMatch(email, pattern);
    }
}

In the above code, we use the IsValidEmail method to verify whether the entered email is legal. This method accepts a string parameter email as the email address entered by the user, then uses the Regex.IsMatch method and a regular expression pattern to verify, and finally returns a Boolean value indicating the input Is the email address legal?

2. Use attributes to verify user input
In C# development, we can also use attributes to verify user input. By defining properties and applying them to corresponding properties, you can check at runtime whether the values ​​of these properties meet specified conditions. Here is an example that demonstrates how to use attributes to verify that the age entered by the user is legal:

using System;
using System.ComponentModel.DataAnnotations;

class Program
{
    static void Main()
    {
        var person = new Person();

        Console.WriteLine("请输入您的年龄：");
        string input = Console.ReadLine();
        person.Age = Convert.ToInt32(input);

        if (Validate(person))
        {
            Console.WriteLine("年龄输入正确");
        }
        else
        {
            Console.WriteLine("年龄输入有误");
        }

        Console.ReadKey();
    }

    static bool Validate(object obj)
    {
        var context = new ValidationContext(obj, serviceProvider: null, items: null);
        var results = new System.Collections.Generic.List<ValidationResult>();
        return Validator.TryValidateObject(obj, context, results, true);
    }
}

class Person
{
    [Range(0, 150)]
    public int Age { get; set; }
}

In the above code, we define a Person class, which contains an Age attribute, and use the Range attribute to specify the range of the attribute. In the Main function, we first create a Person object and set the value of the Age property through user input. Then call the Validate method to verify whether the attributes of the Person object are legal. During the verification process, the Validator.TryValidateObject method is used to verify the properties of the object and return a Boolean value indicating whether the verification is passed.

Conclusion:
By using regular expressions and attributes, we can effectively validate user input. This not only ensures system security, but also improves system stability and user experience. In actual development, we can design and implement more complex input validation mechanisms based on specific needs and business rules to provide better user experience and system security.

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