string.IsNullOrEmpty() in C# for strings is awesome. I pass in a string, it tells me if it was null or blank. Pre-trim it with something like this :
string.IsNullOrEmpty( ( var ?? "" ).Trim() )
and I know if I'm toast or not before the null reference exception or blank screen.
Well, what if I have a List<T>? Or a Dictionary<T,U>? Here's extension methods I wrote for checking blank-ness:
public static bool IsNullOrEmpty<T>( this IList<T> List ) {
return ( List == null || List.Count < 1 );
}
public static bool IsNullOrEmpty<T,U>( this IDictionary<T,U> Dictionary ) {
return ( Dictionary == null || Dictionary.Count < 1 );
}
The added benefit of this is I can say:
myDict.IsNullOrEmpty()
which is usually more like the thought I had when I started writing the code. So I also add this method:
public static bool IsNullOrEmpty( this string String ) {
return string.IsNullOrEmpty( ( String ?? "" ).Trim() );
}
so I can call it like this:
myString.IsNullOrEmpty()
but since I'm coalescing to empty string before trimming, I can just as easily say:
public static bool IsNullOrEmpty( this string String ) {
return ( (String ?? "").Trim() != "" );
}
And for good measure, here's a similar JavaScript function I wrote to check for blank-ness:
function isNullOrEmpty(val) {
var empty = true,
name = null;
if ( typeof(val) === 'undefined' || val === null ) {
return true; // It's null or undefined
}
if ( typeof(val) === 'string' ) {
return (val === ''); // It's a string that may or may not be blank
}
if ( typeof(val) === 'object' ) {
if (value.constructor === Array && val.length === 0) {
return true; // It's an empty array
}
for ( name in val ) {
if ( val.hasOwnProperty(name) ) {
empty = false;
break;
}
}
return empty; // It's an object that has or doesn't have data in it
}
// It's not null or empty
return false;
}
And that, as we say, is null ... or empty. :D
posted @ Tuesday, May 18, 2010 4:43 PM