Simple question regarding null return objects

[Chris]

Hello:

I understand that the DataRow object offers .IsNull(), however once
the object has been retrieved from the row is it enough to just check
for DBNull or should I also check for null? As such:

// Begin C# ADO.NET Code

DataRow dr = GetDataRowFromSomeSource();
Object o = dr[ "existing_column" ];

if ( o is DBNull )
doNullAction();
else if ( o == null )
doNullAction();

// End C# ADO.NET Code

According to what I've read, only this should be necessary:

// Begin C# ADO.NET Code

DataRow dr = GetDataRowFromSomeSource();
Object o = dr[ "existing_column" ];

if ( o is DBNull )
doNullAction();
// No check for null here

// End C# ADO.NET Code

Correct?

 

[Scott M.]

Checking for DBNull is a null check. No need to do it twice.