Validating input values in C#

Question

I began studying C# 5.0 a few days ago and am trying to avoid duplicated code for validation of input values.

class transcript
{
  //Use lamda expression and Func for validation logic
  Func<byte, byte> validate = (grade) =>
  {
    if (grade > 100)
      throw new ArgumentOutOfRangeException("grade can`t be more than 100");
    else
      return grade;
  };

  public string name { get; set; }

  public byte kor
  {
    get { return kor; }
    set { kor = validate(value); }
  }

  public byte eng
  {
    get { return this.eng; }
    set { eng = validate(value); }
  }
}

Answer 1

Per the Capitalization Conventions on MSDN, types, methods, and properties should be PascalCasemeaning they start with an uppercase letter.

---

  Func<byte, byte> validate = (grade) =>
  {
    if (grade > 100)
      throw new ArgumentOutOfRangeException("grade can`t be more than 100");
    else
      return grade;
  };

There is no reason to use a Func here. Just use a normal method, like this

private byte Validate(byte grade)
{
    // the method body can go here
}

---

  public byte kor
  {
    get { return kor; }
    set { kor = validate(value); }
  }

Have you tested this code? The getter and setter both look like a StackOverflowException (via infinite recursion) to me. You need a backing field, like this

private byte kor;
public byte Kor
{
    get { return kor; }
    set { kor = Validate(value); }
}

---

It's uncommon to use byte instead of int, even if you know your data will fit in a byte. Only optimize for size if you know that you need to do so.

Answer 2

Here in this particular example, you can do the same with the help of getter and setter properties. they are capable of doing validations as well. with the help of a back up variable you can achieve the target as like the following:

private byte _Grade;

public byte Grade
{
    get
    {
        return _Grade;
    }
    set
    {
        if (_Grade > 100)
            throw new ArgumentOutOfRangeException("grade can`t be more than 100");
        else
            _Grade = value;
    }
}

So if you are trying to assign a value Greater than 100 it will throw ArgumentOutOfRangeException