Infralution Support

[AB]

In my treeview, I'd like to use a combobox as a cell editor, in which a user can select from the dropdown list, but also edit a value (which isn't added to the dropdown list).
To do this, in the designer I added an editor as System.Windows.Forms.DataGridViewComboBoxEditingControl. In the List-property I added some text values. Then I create a new column and select my new editor as CellEditor.
However, when running the project (VB.NET), I can see the combobox, but it is not filled with items, so there is nothing to select. What am I doing wrong?
Is there another way of creating this type of combobox?

[Infralution]

The editor control (in this case the ComboBox) is just a template for the control(s) actually used by VirtualTree to do the editing - it is not the actual control used. The reflection mechanism used to copy the properties of the template control can cope with most common properties - but the list of items for combo box is beyond its capabilities.

For this reason we provide a separate mechanism to allow you to initialise more complex properties such as this. Add a handler to the CellEditor.InitializeControl event. This is fired prior to the control being displayed - and gives you a chance to initialize properties. The editor controls are cached and reused for performance so this also gives you a chance to reset properties to the defaults if necessary eg:

[AB]

Ok, it works but I don't understand the difference between setting the Datasource for the combobox or using Items.Add.

In the GetCellData event I have the following code:

[Infralution]

When Virtual Tree creates the actual controls used for editing it copies the properties of the template editor control using reflection. This can handle most simple properties like DataSource (where it can just copy the reference), however to copy complex properties like the ComboBox.Items property (which does not have set property accessor) is beyond its capabilities. If you want to initialize these properties then you need to handle the CellEditor.InitializeControl event as discussed previously.
_________________
Infralution Support

[AB]

In other posts I read that it is not the best way to create a new cellEditor and control in the GetCellData event. It should be done at design time or in a constructor. But in my virtual tree I use a combobox with different items for different cells. Do I need to create one combobox (template) and reuse this one for all my cells, and can I change the items in the CellEditor.InitializeControl?

Another problem is that when I have two items in the combobox list, and the user types another value in the combobox (which is not in the list), this value must still be in the textfield part of the combobox when the user opens the combobox list to select another value. Now at that moment the first value from the combobox-list is automatically entered in the textfield part. Is this also something I can change in the CellEditor.InitializeControl?

Thanks a lot for your help,
Anja

[Infralution]

[AB]

In the InitializeControl event handler I change the items, and in de GetCellData event I set the value for the cell, and everything works fine now. Thanks a lot for your support!

Anja