title: Where is the TdxDBTreeListColumn.OnFilterStringUnformat analog in TcxGridDBBandedColumn?
body: <p>We use the DevExpress ExpressQuantumGrid v3 (TdxDBGrid) and ExpressQuantumGrid Suite v12 (TcxGrid) in our application. With the TdxDBGrid, we use the TdxDBTreeListColumn.OnFilterStringFormat and OnFilterStringUnformat events to allow us to filter using string representations of values of the underlying datatype associated with the column. For example, we may have time periods stored in milliseconds, but displayed in HH:MM:SS format.</p>
  
  <p>But I'm stuck with how do do this with the TcxGrid. While I can use the TcxGridDBBandedColumn.OnGetFilterDisplayText as an analog for TdxDBTreeListColumn.OnFilterStringFormat, I'm stuck with how to implement the functionality provided by TdxDBTreeListColumn.OnFilterStringUnformat, to ensure I can convert from the display value specified by the user to the value stored in the underlying dataset.</p>
  
  <p>How is this functionality achieved with the TcxGrid?</p>