RepositoryItem.Modified Event

public event EventHandler Modified

event Public Modified As EventHandler

using System.Windows.Forms;
using DevExpress.XtraEditors;
// ...
private void memoEdit1_Modified(object sender, System.EventArgs e) {
   toolBarSaveButton.Enabled = true;
}

private void toolBar1_ButtonClick(object sender, ToolBarButtonClickEventArgs e) {
   // Checking whether the toolBarSaveButton has been clicked
   if (e.Button == toolBarSaveButton){
      // Validating the memoEdit1
      memoEdit1.DoValidate();
      /*
         * 
         * Here you can save the memoEdit1 contents or 
         * perform some other specific actions in response to button click
         */
      // Making the button disabled
      e.Button.Enabled = false;
   }
}

Imports DevExpress.XtraEditors
' ...
Private Sub MemoEdit1_Modified(ByVal sender As Object, ByVal e As System.EventArgs) _
  Handles MemoEdit1.Modified
    toolBarSaveButton.Enabled = True
End Sub

Private Sub ToolBar1_ButtonClick(ByVal sender As Object, _
  ByVal e As System.Windows.Forms.ToolBarButtonClickEventArgs) Handles ToolBar1.ButtonClick
   ' Checking whether the toolBarSaveButton has been clicked
   If e.Button Is toolBarSaveButton Then
      ' Validating the memoEdit1
      MemoEdit1.DoValidate()
      '
      ' 
      ' Here you can save the memoEdit1 contents or 
      ' perform some other specific actions in response to button click
      '
      ' Making the button disabled
      e.Button.Enabled = False
   End If
End Sub