This might sound like a noob question, but are:
string var;
if (var == null)
and
string var;
if (var == string.Empty)
The same?
Duplicate
What's the Difference between String.Empty and Null? and In C#, should I use String.Empty or Null?
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Duplicate. I've seen this question before. Sigh, now I have to dive through the depths of SO to find it.George Stocker– George Stocker2009-01-23 02:24:45 +00:00Commented Jan 23, 2009 at 2:24
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-1 to Gortok (in theory)... Find the dupe before you vote to close!user27414– user274142009-01-23 02:30:03 +00:00Commented Jan 23, 2009 at 2:30
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Found it, Jon B: stackoverflow.com/questions/151472/…George Stocker– George Stocker2009-01-23 02:50:08 +00:00Commented Jan 23, 2009 at 2:50
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stackoverflow.com/questions/263191/…George Stocker– George Stocker2009-01-23 02:50:42 +00:00Commented Jan 23, 2009 at 2:50
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OK, Gortok - +1 to you (to close, that is).user27414– user274142009-01-23 04:56:25 +00:00Commented Jan 23, 2009 at 4:56
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5 Answers
@Jay is correct, they are not the same. String.IsNullOrEmpty() is a convenient method to check for both null and "".
Comments
No, they are not the same.
string.Empty is the same as "", which is an actual object: a string of 0 length. null means there is no object.
Comments
they are not the same, the implementation of String.IsNullOrEmpty(string) in mscorlib demonstrate it:
public static bool IsNullOrEmpty(string value)
{
if (value != null)
{
return (value.Length == 0);
}
return true;
}
2 Comments
Antonio Pelleriti
sorry, I'm a New User at StackOverflow.com
Matthew Lock
+1 for reminding people to go to the source of the code for learning purposes
No, they are not. First one checks if the variable has been initialized or if it was set to "null" later. Second one checks if the value of the variable is "" (empty). However, you shouldn't use either. You should use string.IsNullOrEmpty(var) instead.
Comments
But sometimes you want to know if the string is NULL and it does not matter that its empty (in a OO design). For example you have a method and it will return NULL or a string. you do this because null means the operation failed and an empty string means there is no result.
In some cases you want to know if it failed or if it has no result prior to take any further actions in other objects.
