title: Add "All" option to ComboBox used to filter for report in MS Access
body: <p>I'm trying to follow <a href="http://support.microsoft.com/kb/210290" rel="nofollow">Microsoft's example</a> on how to add an "All" option to a ComboBox in Microsoft Access, but their article does not do an adequate job of providing guidance, aside from specifying the code.</p>
  
  <p>What I'm trying to do is build a form that allows a user to select an option from a ComboBox (the options are generated from records in a table), and then build a report filtered based on the user's selected option. The ComboBox consists of 2 columns: the primary key/ID of the records and their displayable names. </p>
  
  <p>I can't understand the VBA code Microsoft provides enough to figure out what is going on, but I would like the "All" option in my ComboBox to either have a blank primary key/ID, or one that = 0. That isn't the case, as selecting the "All" option when using the form results in the error message "The value you entered isn't valid for this field". This leads me to believe that the "All" text is getting filled into the primary key/ID column instead of the display column. The example instructs me to assign the display column number as the "Tag" property of the ComboBox - and in this case, my display column number is 2. However, this (and pretty much any other value I add) results in the aforementioned error message. </p>
  
  <p>Any idea if Microsoft's example is even applicable to my case, or do I need to adjust their code somehow?</p>