如何确定字符串是否为int或double类型，以用于重载方法？ C＃

Question

I want to call an overload method using the value that was inserted into my texbox. By default it is of value string, so I have to check if it is of type int or double. I am using the TryParse() to check and see if the values are of either int or double, but it causes me to have 2 variables for each textbox. I only want the 2 variables that has been successful. I do not know how to determine which has been successful so that I can use them in the overload method call.

My code looks like this...

        string a = textBox1.Text, b = textBox2.Text;
        int f;
        double d;
        if(int.TryParse(a, out f))
        {
        }
        else if(double.TryParse(a, out d))
        {
        }
        int s;
        double sD;
        if (int.TryParse(b, out s))
        {
        }
        else if(double.TryParse(b, out sD))
        {
        }
        double x;
        //Do not know which values to pass, because i only want the 2 
        //that was successful
        Area(?, ?, out x);
        label3.Text = "This is the value " + x;
    }
    private static void Area(int a, int b, out double x)
    {
        x = a * b;
    }
    private static void Area(double a, double b, out double x)
    {
        x = a * b;
    }
    private static void Area(int a, double b, out double x)
    {
        x = a * b;
    }

If I then nest the if else statements, the compiler gives me an error saying that the double value is unassigned. I know a bunch of if else statements are ugly code, but it is the only way I currently know how.

        if(f == '\0' && s == '\0')
        { Area(d, sD, out sum); }
        else if(d=='\0' && s=='\0')
        {Area(f, sD, out sum;)}
        //and so on...

Answer 1

The simplest form i can come up with is putting the TryParses in sequence in a single if statement and, handling the first one that succeeds.

This leaves the possibility that one string cannot be parsed (or neither), so in that case i am throwing an exception

int intA;
int intB;

double doubleA;
double doubleB;
double x;

if(int.TryParse(a, out intA) && int.TryParse(b, out intB))
{
   Area(intA, intB, out x);
}
else if (double.TryParse(a, out doubleA) && double.TryParse(b, out doubleB))
{
   Area(doubleA, doubleB, out x);
}
else
{
   throw new ArgumentException("cannot parse one or both numbers");
}

label3.Text = "This is the value " + x;