I went for Ncalc. I am posting my codes for future users who will be on same problems like me.
1.Download the Ncalc(Binaries)http://ncalc.codeplex.com/releases/view/73656
- Reference the dll in your solution.(Right click > add reference > Browse > NCalc.dll)
In codes
Using NCalc;
3.May be used as
public Double Calculate(string argExpression)
{
//get the user passed string
string ExpressionToEvaluate = argExpression;
//pass string in the evaluation object declaration.
Expression z = new Expression(ExpressionToEvaluate);
//command to evaluate the value of the **************string expression
var result = z.Evaluate();
Double results = Convert.ToDouble(result.ToString());
return results;
}