Gets or sets the value of the field as a 64-bit signed integer. Double, String, Boolean, Int32, and Int64 values are converted; a TimeStamp gives its seconds in the high 32 bits and its increment in the low 32 bits. Returns a null reference (Nothing in Visual Basic) for a missing field; throws System.InvalidOperationException for the other types. The value is written as Int64.

'Declaration
 
Public Property AsInt64 As Nullable(Of Long)

public Nullable<long> AsInt64 {get; set;}