Running Collection of Extension Methods

extensionUtils.cs

//yeah yeah this isn't a fully formatted .cs file I know
//just put these somewhere, probably with the following:
//using System;
//using System.Linq;

//following datetime exts are good for output from db results, esp. for reporting

public static string ToStringOrNA(this DateTime? dt)
{
    if (dt.HasValue)
    {
        return dt.Value.ToString();
    }
    else
    {
        return "N/A";
    }
}

public static string ToStringOrDefaultValue(this DateTime? dt)
{
    if (dt.HasValue)
    {
        return dt.Value.ToString();
    }
    else
    {
        return "N/A";
    }
}

public static string ToShortDateStringOrNA(this DateTime? dt)
{
    if (dt.HasValue)
    {
        return dt.Value.ToShortDateString();
    }
    else
    {
        return "N/A";
    }
}

public static string ToShortDateStringOrDefault(this DateTime? dt, string defaultValue)
{
    if (dt.HasValue)
    {
        return dt.Value.ToshortDateString();
    }
    else
    {
        return defaultValue;
    }
}

//a few more mostly for output of DB data
//nullDefault is usually "N/A" or "Unknown" or smtn...
public static string BoolToYN(this bool? value, string nullDefault)
{
    string result;

    if (value == null)
    {
        result = nullDefault;
    }
    else
    {
        result = ((bool)value).BoolToYN();
    }

    return result;
}

public static string BoolToYN(this bool value)
{
    return value ? "Yes" : "No";
}

//quick checks of contents
//this is where we use LINQ

public static bool IsOneOf<T>(this T needle, params T[] haystack)
{
    return haystack.Contains(needle);
}

public static bool IsNoneOf<T>(this T needle, params T[] haystack)
{
    return !haystack.Contains(needle);
}