private bool? _isDataFeed;
public bool isDataFeed
{
    get
    {
	if (_isDataFeed == null)
	{
	    string header = Request.Headers["X-Requested-With"];
            _isDataFeed = (!String.IsNullOrEmpty(header) && header.ToLower() == "xmlhttprequest");
 
	}
	return (bool)_isDataFeed;
    }
    set
    {
	_isDataFeed = value;
    }
}
 

 
private bool _isDataFeed;
public bool isDataFeed
{
    get
    {
	string header = Request.Headers["X-Requested-With"];
	_isDataFeed = (!String.IsNullOrEmpty(header) && header.ToLower() == "xmlhttprequest");
	return _isDataFeed;
    }
    set
    {
	_isDataFeed = value;
    }
}
 

Assuming that Request.Headers["X-Requested-With"] can change (and I would assume it can), the two are functionally quite different.

And, yes, the setter is redundant in the second one.

.meic | fruuti

private bool? _isDataFeed;
public bool isDataFeed
{
    get
    {
	if (!_isDataFeed.HasValue)
	{
	    string header = Request.Headers["X-Requested-With"];
            _isDataFeed = ((!String.IsNullOrEmpty(header)) && header.Equals("xmlhttprequest", StringComparison.InvariantCultureIgnoreCase));
 
	}
	return _isDataFeed.Value;
    }
    set
    {
	_isDataFeed = value;
    }
}

My, someone's been reading Effective C#. Or, in fact, probably More Effective C#.

Good books. We have them in our lounge, somewhere.

.meic | fruuti