.Net Windows Application - using tableadapters and clearing dataset before page load
<p>I have a .Net windows forms application, and I need to load values into some combo boxes from tables in a database.  Now, the windows forms applications don't appear to work the same way as .Net web apps.  What I did, after reading the help information, was:</p>

<ol>
<li><p>Create the data set in the "Data Sources" section of VS2008,
specifying the table and columns I wanted returned</p></li>
<li><p>This set up as well as the dataset in my form three other objects, a
"binding source" object, a table adapter and a tableadaptermanager.</p></li>
<li><p>In my combobox, I set the datasource property to the newly created
bindingsource object, and the DisplayMember property to the column
with the data that I wanted added.  So far, so good.</p></li>
</ol>

<p>Now, time to test.  I run the app in debug mode - and the combobox gets populated with the values that I expected.  I select a value, a postback occurs, and then I get an error at pageload:  ConstraintException was unhandled.  Column 'name' is constrained to be unique. Value 'value I selected' is already present.</p>

<p>Ok, someone's not playing the cards I dealt them.  The "ClearBeforeFill" property on the table adapter is set to True, and in the page_load section I even explicitly put a line in calling the Clear() method on my data table.  What have I forgotten?</p>
