Validation with Regular expression

Validation code behind using Regularexpression class Regex 

//Calling method

value  = yourvalue(string,int or Email)

bool bCheck = NumberValidation(value);  - Calling method

bCheck  -- Return Value

if (bCheck == false)

{

 //not matching

}

Else

{

 //matching

}

1. Number validation  - Only numbers (1,2,3,...)

private bool NumberValidation(string value)

{

Regex regex = new Regex("^[0-9]*$");

if (regex.IsMatch(value))

{

countCheck = 0;

return true;

}

else

{

if (countCheck == 1 && tPalceholdervalue != "")

{

countCheck = 0;

MessageBox.Show("Only numbers may be entered here", "Restriction");

return false;

}

return false;

}

}

2. Alphanumeric  (combination numbers and alphabets )

private bool AlphNumeric(string value)

{

Regex regex = new Regex(@"[a-zA-Z0-9/'.]{1,40}");

if (regex.IsMatch(value))

{

countCheck = 0;

return true;

}

else

{

if (countCheck == 1 && tPalceholdervalue != "")

{

countCheck = 0;

MessageBox.Show("No Special Characters", "Restriction");

return false;

}

return false;

}

}

3.Email Validation

private bool EmailCheck(string value)

{

Regex regex = new Regex(@"^(?("")("".+?""@)|(([0-9a-zA-Z]((\.(?!\.))|[-!#\$%&'\*\+/=\?\^`\{\}\|~\w])*)(?<=[0-9a-zA-Z])@))(?(\[)(\[(\d{1,3}\.){3}\d{1,3}\])|(([0-9a-zA-Z][-\w]*[0-9a-zA-Z]\.)+[a-zA-Z]{2,6}))$");

if (regex.IsMatch(value))

{

countCheck = 0;

return true;

}

else

{

if (countCheck == 0 && tPalceholdervalue != "")

{

countCheck = 1;

MessageBox.Show("Ex: yourname@email.com", "Restriction");

return false;

}

return false;

}

}

4. Name Validation

private bool NameValidation(string value)

{

value = value.TrimEnd();

Regex regex = new Regex(@"^[0-9a-zA-Z ]+$");

if (regex.IsMatch(value))

{

countCheck = 0;

return true;

}

else

{

if (countCheck == 1 && tPalceholdervalue != "")

{

countCheck = 0;

MessageBox.Show("Special Characters are not allowed", "Restriction");

return false;

}

return false;

}

}

5. Date Validation 

private bool DateValidation(string value)

{

Regex regex = new Regex(@"\d{1,2}\/\d{1,2}/\d{4}");

if (regex.IsMatch(value))

{

countCheck = 0;

return true;

}

else

{

if (countCheck == 1 && tPalceholdervalue != "")

{

countCheck = 0;

MessageBox.Show("Date format : MM/DD/YYYY", "Restriction");

return false;

}

return false;

}

}

6. Boolean Validation

private bool BooleanValidation(string value)

{

if (value.ToUpper() == "YES" || value.ToUpper() == "NO")

{

countCheck = 0;

return true;

}

else

{

if (countCheck == 1 && tPalceholdervalue != "")

{

countCheck = 0;

MessageBox.Show("Ex: Yes or No", "Restriction");

return false;

}

return false;

}

}