Don't ever rely on user input! This package offers the ability to trim every string in a class. Sanitizing input data before processing is beneficial.

Please take a look at the Source Genarator based string trimmer. It's faster! https://github.com/DimonSmart/StringTrimmerGenerator

Standard class for describing a user.

public class User
{
   public string Name {get; set;}
   public string Surname {get; set;}
   public string Secondname {get; set;}
   public string UserName {get; set;}
   public string Email {get; set;}
   public string Phone {get; set;}
}

Usage of the User class to add a new User record to the database is typical.

Try 
public void CreateUser (User user)
{
   user.Name = user.Name.Trim();
   user.Surname = user.Surname.Trim();
   user.Secondname = user.Secondname.Trim();
   user.Email = user.Email.Trim();
   user.Phone = user.Phone.Trim();
}

Error: UserName Trim command is missing. Due to the tiny difference in UserName, this allows for many users while having only one real user.

• "John Doe "
• " John Doe"
• " John Doe "
• "John Doe"

Having the same user registered many times irritates the support personnel!

Note: It is usual for users to not merely input a UserName during registration, but to copy it from other sources with different spaces surrounding (and inside) the name.

Try 
public void CreateUser (User user)
{
   user.TrimExtraSpaces(); // Just one line
}