Answer by Wayne for Difference in months between two dates

This is from my own library, will return the difference of months between two dates.

public static int MonthDiff(DateTime d1, DateTime d2){    int retVal = 0;    // Calculate the number of years represented and multiply by 12    // Substract the month number from the total    // Substract the difference of the second month and 12 from the total    retVal = (d1.Year - d2.Year) * 12;    retVal = retVal - d1.Month;    retVal = retVal - (12 - d2.Month);    return retVal;}