Nullable Types

[Andrew Robinson]

Quick question:

is there a difference between these?

Given a nullable type:

int? i = null;

// option 1
if(i.HasValue) { }

and

// option 2
if(i != null) {}

Why would you use one form over the other?

 

[Jon Skeet [C# MVP]]

is there a difference between these?

Given a nullable type:

int? i = null;

// option 1
if(i.HasValue) { }

and

// option 2
if(i != null) {}

Why would you use one form over the other?

They compile to the same code - it's just a case of which you find more
readable.

 

[Jeffrey Tan[MSFT]]

Hi Andrew,

Yes, Jon is right. "==" and "!=" operation will call the Equals(object
other) method to do the comparison. Below is the source code I got from
System.Nullable<T> type:

public override bool Equals(object other)
{
if (!this.HasValue)
{
return (other == null);
}
if (other == null)
{
return false;
}
return this.value.Equals(other);
}

As you can see, "i!=null" has the same logic as "i.HasValue" property.

Thanks.

Best regards,
Jeffrey Tan
Microsoft Online Community Support
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[Jeffrey Tan[MSFT]]

Hi Andrew,

Have you reviewed our replies to you? Does it make sense to you? If you
still need any help, please feel free to feedback, thanks.

Best regards,
Jeffrey Tan
Microsoft Online Community Support
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Note: The MSDN Managed Newsgroup support offering is for non-urgent issues
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Engineer within 1 business day is acceptable. Please note that each follow
up response may take approximately 2 business days as the support
professional working with you may need further investigation to reach the
most efficient resolution. The offering is not appropriate for situations
that require urgent, real-time or phone-based interactions or complex
project analysis and dump analysis issues. Issues of this nature are best
handled working with a dedicated Microsoft Support Engineer by contacting
Microsoft Customer Support Services (CSS) at
http://msdn.microsoft.com/subscriptions/support/default.aspx.
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This posting is provided "AS IS" with no warranties, and confers no rights.