Simple IsNum() function in C#

I disparately needed a C#'s equivalent for "IsNum". I was surprised that there isn't one, so I decided to write my own. There are many ways that can be used to write this functions. However, my task required that I should be able to verify any type of number (int, double, etc.) and get either True/False return values. Below is the code that I am using to solve this problem.

public static bool IsNumeric(object Expression)
{

// Variable to collect the Return value of the TryParse method.

bool isNum;


// Define variable to collect out parameter of the TryParse method. If the conversion fails, the out parameter is zero.

double retNum;


// The TryParse method converts a string in a specified style and culture-specific format to its double-precision floating point number equivalent.

// The TryParse method does not generate an exception if the conversion fails. If the conversion passes, True is returned. If it does not, False is returned. Hence no need for try..catch block

isNum = Double.TryParse(Convert.ToString(Expression), System.Globalization.NumberStyles.Any, System.Globalization.NumberFormatInfo.InvariantInfo, out retNum);

return isNum;

}