void SetPatterns()
{
string patternNumber = @"(?<numb>\-?\d+([\.,]\d+)?(E[\+\-]\d{1,2})?)";
string patternOperator = @"(?<operator>[\+\-\*/\^])";
string patternLast = @"(?<last>[^\d\.,E])";
string sOperation = string.Format(
@"{0}\s*{1}\s*{2}\s*{3}",
patternNumber.Replace("numb", "arg1"),
patternOperator,
patternNumber.Replace("numb", "arg2"),
patternLast);
expression = new Regex(sOperation, RegexOptions.Compiled);
}