Question

How do I check Nulls in Linq?

I have a third-party code that returns a DataTable with a column type DateTime that is nullable.

My code:

 var profile = (from d in ds.Tables[0].AsEnumerable()
               select new User
               {
                 FirstName = d["FirstName"].ToString(), 
                 Birthdate = Convert.ToDateTime(d["BirthDate"].ToString())
               }).FirstOrDefault();

returns an error that the Object cannot be cast from DBNull to other types on the Birthdate= statement.

I tried using the following code but returns a cast exception (Cannot cast from string to DateTime?)

Birthdate = (DateTime?)d["BirthDate"].ToString();

Is there a way to short-hand checking the null values?

Answer 1

I have not tested this, but you can try the following:

Birthdate = d.Field<DateTime?>("BirthDate")

From MSDN:

The Field method provides support for accessing columns as nullable types. If the underlying value in the DataSet is [DBNull.]Value, the returned nullable type will have a value of null.