title: ColumnChart with dynamic number of columns
body: <p>I have a question about the ColumnChart in Flex 3.
  a simple ColumnChart is like:</p>
  
  <p></p>
  
  <pre><code>    &lt;mx:horizontalAxis&gt;
         &lt;mx:CategoryAxis 
              dataProvider="{myDP}" 
              categoryField="date"
         /&gt;
      &lt;/mx:horizontalAxis&gt;
  
      &lt;mx:series&gt;
           &lt;mx:ColumnSeries 
                  xField="date" 
                  yField="Expense" 
                  displayName="Expense"
             /&gt;
             &lt;mx:ColumnSeries 
                  xField="date" 
                  yField="Income" 
                  displayName="Income"
             /&gt;
        &lt;/mx:series&gt;
  </code></pre>
  
  <p></p>
  
  <p>But how to make a ColumnChart with dynamic number of columns which come from the dataprovider? Here the columns for "expense" and "income" are hardcoded. But how can we do if they come from the dataprovider, and number is not fixed, for example, yFields can be "expense 1", "expense 2", ... "Income 1", "Income 2", ...etc. </p>