C#/.NET: Safe way to convert UTC time to local time when databinding

After reading Scott Mitchell’s article Using Coordinated Universal Time (UTC) to Store Date/Time Values, I decided to do as he suggest and use UTC for a web application I’m building at work. All in all it is fairly easy to deal with UTC in the .NET Framwork. There is a DateTime.UtcNow you can use instead of the regular DateTime.Now property, and there is a DateTime.ToLocalTime method that will convert your UTC DateTime value to the local server time zone, even taking daylight savings time in to consideration. When converting the other way, the DateTime.ToUniversalTime method is provided.

With MsSQL’s getutcdate() function (instead of getdate()), just about everything is smooth sailing. The only problem I have encountered is when binding a to a ASP.NET server control. Scott suggests doing like this:

((DateTime) Eval("DateUpdated")).ToLocalTime()

This only works when DateUpdated is not null, which is not always the case in my application. To get around this, I created the following simple class and stuck it in my App_Code folder.

public static class Extensions
{
    /// <summary>
    /// If object is a DateTime, it will convert
    /// the DateTime to local time.
    /// </summary>
    /// <param name="obj"></param>
    /// <returns></returns>
    public static object ToLocalTime(this object obj)
    {
        if (obj is DateTime)
            return ((DateTime)obj).ToLocalTime();
        else
            return obj;
    }
}

The method ToLocalTime(this object obj) uses the extension method feature in .NET 3.0, that allows you to extend the functionality of other class. Here I extend upon Object, adding a .ToLocalTime() method to it. This allows me to use it in ASP.NET server controls like this:

Eval("DateUpdated").ToLocalTime()

This works because Eval() returns a object, which is also the reason why I did not extend a more specific class.