DBNull warnings when performing stored procedure

One column in my database (of type double) has some null values. I am executing a sored procedure to get the data in my app

 wipDBTableAdapters.XLSFacturiTableAdapter TAFacturi = new wipDBTableAdapters.XLSFacturiTableAdapter();
               var dtfacturi = TAFacturi.GetData(CodProiect);

Then i try to do something like this:

if (dtfacturi[i].CANTITATE == null)
   {
    //do something
   }

this is giving a warning :

The result of the expression is always 'false' since a value of type 'double' is never equal to 'null' of type 'double?

However when i run my code i ge开发者_运维技巧t the following exception:

StrongTypingException
The value for column 'CANTITATE' in table 'XLSFacturi' is DBNull. 

How am I supposed to resolve this ?

While working with data in DB and need to check NULL values use DBNull class instead of .NET null.

Database NULLs are different from null, you should use IsDBNull to check for database NULLs.

Edit: Mixed up VB.Net with C#

Compare with DBNull.Value rather than the VB specific IsDBNull.

Try this:

if (dtfacturi[i].CANTITATE == DBNull.Value)
{
  //do something
}

A value of type 'double' is indeed never null; if you want to export into an array of doubles, you need to have two columns in the database, one containing the data and one containing a flag as to whether the data is valid or not.

This is really a bug in your database-to-array adapter code; I can't find any google hits for XLSFacturiTableAdapter so I'm not sure who to shout at.

DBNull is not null

Check DBNull documentation on MSDN

Try this test :

if (DBNull.Value.Equals(dtfacturi[i].CANTITATE))
{
    //do something
}

When using TypedDataSets, check if coloumn is null this way..

   if (dtfacturi[i].IsCANTITATENull()) 
   { 
       //do something 
   } 

Also note that, C# null is different than Database null. Type of your coloumn is double which is a value type that can never be null. In order to check if your coloumn value is null you need to compare it with DBNull.Value.