title: .NET DBNull vs Nothing across all variable types?
body: <p>I am a little confused about null values and variables in .NET. (VB preferred)</p>
  
  <p>Is there any way to check the "nullness" of ANY given variable regardless of whether it was an object or a value type? Or does my null check have to always anticipate whether it's checking a value type (e.g. System.Integer) or an object? </p>
  
  <p>I guess what I'm looking for is a function that checks all possible kind of null-ness. That is, any type of variables that </p>
  
  <p>a) were never assigned a value since declared</p>
  
  <p>b) were assigned a null value from a data object (that came from a database)</p>
  
  <p>c) were set equals to another variable value which was null</p>
  
  <p>d) were set to an ASP.NET session/application variable that was never set or expired.</p>
  
  <p>Is there a general best-practice when it comes to handling null scenarios in .NET?</p>
  
  <p><strong>UPDATE:</strong> When I talk about a value type being "null", what I really mean is a value type that was either never set or was at some point set equal to or cast from a null object. </p>