Unable to convert string (containing a number) to int?

Try this:

int inputNumber = Int32.Parse(inputString, NumberStyles.AllowDecimalPoint);

800.000

is of type Double, not an Integer

so,

double inputNumber = Double.Parse(inputString);

Will work for you.

The Exception occurs because your string is no int32. You have to convert to double first.

double value = Convert.ToDouble(youString);

Try this:

double myDouble = Convert.ToDouble(string);

works similarly with other types too,

int myInt = Convert.ToInteger(string);

Since you are passing a number that's got decimals, you'll need to use the appropriate target type - float or double

So that gives you

var value = Double.Parse(s);

You can take away the decimals like this:

var integer = (int)value;

But even with the Double.Parse you'll need to be careful, since it will expect different input based on the current culture (System.Globalization.CultureInfo.CurrentCulture).

So while

Double.Parse("800.00", System.Globalization.CultureInfo.GetCultureInfo("en-US"))

works as expected

Double.Parse("800.00", System.Globalization.CultureInfo.GetCultureInfo("de-DE"))

will produce the value "80000"

EDIT1 - added:

So you'll might want to use

Double.Parse("800.00", System.Globalization.CultureInfo.InvariantCulture)

to prevent any misinterpretation that can lead to all kinds of trouble.

Int32 valueInInt = (int)double.Parse(inputString);