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Next lesson:

Getting to know the Web Controls

Lesson 8 - WebColumnCombo

The WebColumnCombo is a control that displays a combobox within a WebGrid. 

You can use events after someone selects a dropdown item. Commonly used events are the “OnFill” event and the “OnChange” event. 

  • You can use the “OnFill” event to add initial values to the WebColumnCombo. 
  • The “Onchange” event can be used to trigger a specific action. For example: “Saving the current record”.

Now you know more about the WebColumnCombo, I will show you how to implement it and how it looks.


  • I already created an empty WebView for this example. 
  • By navigating to the DDO explorer I have added two DDO’s.
  • These DDO’s are created from the table “product” and its parent table “City”. These tables are related on the column “CityID”.
  • I open the WebApp Designer.
  • Now that we have data to work with, we will add a “datagrid” and the “cWebColumnCombo” inside it.
  • By clicking on the component and then navigating to “properties”, we can add specific events. 
  • We will add the “OnFill” event and the “OnChange” event by double clicking on the name of the event.
  • We will also add the “OnNavigateForward” event to the view. This event will be used for filling the list initially.
  • The next step is to add an entry_item to the “WebColumnCombo” and add logic to the “OnFill” and the “OnChange” event.
  • In the “OnFill” event we fill the list with combo items. Initially with data form the city table. 
  • The procedure “AddComboItem” can be used to add the items.
  • In the “OnChange” event I have created a “save” procedure  for saving the city to the “products” table.
  • Be careful, enable the pbServerOnChange property, otherwise the “OnChange” event won’t be triggered.
  • I have also added the name of the product as a webcolumn, so we have got some dummy data in the table.
  • Now compile/run and there you go. Here we have a fully working WebColumnCombo.