In VB, there is a IsDBNull function that checks to see if a value in a DataReader is null. It’s usage goes something like this:
VB
If IsDBNull(dr("first_name")) = False Then
' Do something, first_name is not null
End If
The C# equivalent of this would look something like this:
if (dr["first_name"] != System.DBNull.Value)
{
// Do something, first_name is not null
}