How to convert "0" and "1" to false and true

In a single line of code:

bool bVal = Convert.ToBoolean(Convert.ToInt16(returnValue))

If you want the conversion to always succeed, probably the best way to convert the string would be to consider "1" as true and anything else as false (as Kevin does). If you wanted the conversion to fail if anything other than "1" or "0" is returned, then the following would suffice (you could put it in a helper method):

if (returnValue == "1")
{
    return true;
}
else if (returnValue == "0")
{
    return false;
}
else
{
    throw new FormatException("The string is not a recognized as a valid boolean value.");
}

You can use that form:

return returnValue.Equals("1") ? true : false;

Or more simply (thanks to Jurijs Kastanovs):

return returnValue.Equals("1");

How about:

return (returnValue == "1");

or as suggested below:

return (returnValue != "0");

The correct one will depend on what you are looking for as a success result.