求C#计算器完整代码！！！谢谢！！！
望高手发给本人邮箱 sunle0710@126.com
希望窗体和控制台各一份！
只需要实现 简单的加减乘除，以及符号问题就ok!
谢谢！



------解决方案--------------------
public class Operation 
{ 
private double _numberA = 0; 
private double _numberB = 0; 
public double NumberA 
{ 
get 
{ 
return _numberA; 
} 
set 
{ 
_numberA = value; 
} 
} 
public double NumberB 
{ 
get 
{ 
return _numberB; 
} 
set 
{ 
_numberB = value; 
} 
} 
public virtual double GetResult() 
{ 
double result = 0; 
return result; 
} 
public static string checkNumberInput(string currentNumber, string inputString) 
{ 
string result = ""; 
if (inputString == ".") 
{ 
if (currentNumber.IndexOf(".") < 0) 
{ 
if (currentNumber.Length == 0) 
result = "0" + inputString; 
else 
result = currentNumber + inputString; 
} 
} 
else if (currentNumber == "0") 
{ 
result = inputString; 
} 
else 
{ 
result = currentNumber + inputString; 
} 

return result; 
} 


} 
class OperationAdd : Operation 
{ 
public override double GetResult() 
{ 
double result = 0; 
result = NumberA + NumberB; 
return result; 
} 
} 
class OperationSub : Operation 
{ 
public override double GetResult() 
{ 
double result = 0; 
result = NumberA - NumberB; 
return result; 
} 
} 
class OperationMul : Operation 
{ 
public override double GetResult() 
{ 
double result = 0; 
result = NumberA * NumberB; 
return result; 
} 
} 
class OperationDiv : Operation 
{ 
public override double GetResult() 
{ 
double result = 0; 
if (NumberB == 0) 
throw new Exception("除数不能为0。"); 
result = NumberA / NumberB; 
return result; 
} 
} 
class OperationSqr : Operation 
{ 
public override double GetResult() 
{ 
double result = 0; 
result = NumberB * NumberB; 
return result; 
} 
} 
class OperationSqrt : Operation 
{ 
public override double GetResult() 
{