Codeplex Coding Guidelines
A set of coding guidelines for C# 3.0, C# 4.0 and C# 5.0, design principles and layout rules for improving the overall quality of your code development.
Category: C#
C# Tips n Tricks: Get Decimal Places
I needed a quick way to get the number of decimal places on a Double value. I am displaying the values differently if they have more than 2 decimal values. Here is a quick helper that I threw together.
public static int GetDecimalCount(this double value)
{
var str = value.ToStringOrEmpty();
if (!str.Contains("."))
return 0;
return str.Substring(str.IndexOf(".") + 1).Length;
}
C# Tips n Tricks: Simple IsHoliday Class
Today I had a need to check if the current date was a holiday. I wrote up this quick class to do the calculations. This may be a good class to add as an extension to the DateTime class as well. It is one of those nice simple classes that is always useful.
public class Holiday
{
public static bool IsHoliday(DateTime date)
{
return
Holiday.IsNewYearsDay(date)
|| Holiday.IsNewYearsEve(date)
|| Holiday.IsThanksgivingDay(date)
|| Holiday.IsDayAfterThanksgiving(date)
|| Holiday.IsChristmasEve(date)
|| Holiday.IsChristmasDay(date)
|| Holiday.IsFourthOfJuly(date)
|| Holiday.IsLaborDay(date)
|| Holiday.IsMemorialDay(date);
}
public static bool IsNewYearsDay(DateTime date)
{
return date.DayOfYear == AdjustForWeekendHoliday(new DateTime(date.Year, 1, 1)).DayOfYear;
}
public static bool IsNewYearsEve(DateTime date)
{
return date.DayOfYear == AdjustForWeekendHoliday(new DateTime(date.Year, 12, 31)).DayOfYear;
}
public static bool IsChristmasEve(DateTime date)
{
return date.DayOfYear == AdjustForWeekendHoliday(new DateTime(date.Year, 12, 24)).DayOfYear;
}
public static bool IsChristmasDay(DateTime date)
{
return date.DayOfYear == AdjustForWeekendHoliday(new DateTime(date.Year, 12, 25)).DayOfYear;
}
public static bool IsFourthOfJuly(DateTime date)
{
return date.DayOfYear == AdjustForWeekendHoliday(new DateTime(date.Year, 7, 4)).DayOfYear;
}
public static bool IsLaborDay(DateTime date)
{ // First Monday in September
DateTime laborDay = new DateTime(date.Year, 9, 1);
DayOfWeek dayOfWeek = laborDay.DayOfWeek;
while (dayOfWeek != DayOfWeek.Monday)
{
laborDay = laborDay.AddDays(1);
dayOfWeek = laborDay.DayOfWeek;
}
return date.DayOfYear == laborDay.DayOfYear;
}
public static bool IsMemorialDay(DateTime date)
{ //Last Monday in May
DateTime memorialDay = new DateTime(date.Year, 5, 31);
DayOfWeek dayOfWeek = memorialDay.DayOfWeek;
while (dayOfWeek != DayOfWeek.Monday)
{
memorialDay = memorialDay.AddDays(-1);
dayOfWeek = memorialDay.DayOfWeek;
}
return date.DayOfYear == memorialDay.DayOfYear;
}
public static bool IsThanksgivingDay(DateTime date)
{//4th Thursday in November
var thanksgiving = (from day in Enumerable.Range(1, 30)
where new DateTime(date.Year, 11, day).DayOfWeek == DayOfWeek.Thursday
select day).ElementAt(3);
DateTime thanksgivingDay = new DateTime(date.Year, 11, thanksgiving);
return date.DayOfYear == thanksgivingDay.DayOfYear;
}
public static bool IsDayAfterThanksgiving(DateTime date)
{//Day after Thanksgiving
var thanksgiving = (from day in Enumerable.Range(1, 30)
where new DateTime(date.Year, 11, day).DayOfWeek == DayOfWeek.Thursday
select day).ElementAt(3);
DateTime thanksgivingDay = new DateTime(date.Year, 11, thanksgiving + 1);
return date.DayOfYear == thanksgivingDay.DayOfYear;
}
private static DateTime AdjustForWeekendHoliday(DateTime holiday)
{
if (holiday.DayOfWeek == DayOfWeek.Saturday)
{
return holiday.AddDays(-1);
}
else if (holiday.DayOfWeek == DayOfWeek.Sunday)
{
return holiday.AddDays(1);
}
else
{
return holiday;
}
}
}
C# Tips n Tricks: ToTitleCase()
This is yet another simple tool that makes my life easier on occasion. All it does is capitalize every word in the string.
public static string ToTitleCase(this string str)
{
return CultureInfo.CurrentCulture.TextInfo.ToTitleCase(str.ToLower());
}
C# Tips n Tricks: ToStringOrEmpty()
Here is another one of those extension methods that I carry with me from job to job. It’s a super simple one that just makes sense. So many times I am working with variables that need to be displayed as empty strings when they are null. The following code gets tiresome when generating dozens of strings in a row.
var displayString = value == null ? String.Empty : value.ToString();
Instead I added the following extension method for strings. Technically it works for any object that has ToString() implemented.
It means that I can simply show the following code which is much simpler and nicer and cleans my code up tremendously.
public static string ToStringOrEmpty(this object value)
{
return ((object)value ?? String.Empty).ToString();
}
Update: A former co-worker sent me this CodeProject Article: Chained null checks and the Maybe monad that takes this concept a bit further with a fairly complex set of extensions that allow cleaning up null checks even more. I’ll have to dig into it deeper.
C# Tips n Tricks: Adding a "From Camel Case" string extension method
On occasion I am working with strings that are simply the enum value, such as “MyEnum.SampleEnumName”. I want to display it as a string without the camelcase formatting “Sample Enum Name”. To do this I added the following FromCamelCase extension method to string.
namespace CustomExtensions
{
public static class StringExtension
{
public static string ToStringOrEmpty(this object value)
{
return string.Concat(value, "");
}
/// <summary>
/// Converts a string from CamelCase to a human readable format.
/// Inserts spaces between upper and lower case letters.
/// Also strips the leading "_" character, if it exists.
/// </summary>
/// <param name="propertyName"></param>
/// <returns>A human readable string.</returns>
public static string FromCamelCase(this string propertyName)
{
string returnValue = null;
returnValue = propertyName.ToStringOrEmpty();
//Strip leading "_" character
returnValue = Regex.Replace(returnValue, "^_", "").Trim();
//Add a space between each lower case character and upper case character
returnValue = Regex.Replace(returnValue, "([a-z])([A-Z])", "$1 $2").Trim();
//Add a space between 2 upper case characters when the second one is followed by a lower space character
returnValue = Regex.Replace(returnValue, "([A-Z])([A-Z][a-z])", "$1 $2").Trim();
return returnValue;
}
}
}
Amy's Tech Notes 