Infralution Support

salomo · Guest

I'm looking for simple example for programmatic data binding which use the event handling method.
For a simple test I have added one column and overwritten the GetCellData event:

private void virtualTree1_GetCellData(object sender, GetCellDataEventArgs e)
{
e.CellData.Value = "test";
}

But this has no effect, because the event will not fired. Question

Thanks

Infralution · Joined: 28 Feb 2005 Posts: 5027

You have to do two other things. First set the datasource. The object you set as datasource acts as the root node for the tree. Second you must also handle the GetChildren event to (at least) provide the children for the root node.

Here is a minimal example:

salomo · Joined: 05 Apr 2005 Posts: 13 Location: Potsdam (Germany)

Thanx, Really fast support Smile

That helps. I have adapted this example to bind my objects to the treelist.
But how can make changes in my object's when I use a celleditor in the VirtualTree. Which event from which control (treeList or Column or CellEditor) is responsible to update my object data.

Cheers & Thanx salomo

Infralution · Joined: 28 Feb 2005 Posts: 5027

Have a look at the SetCellValue event
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Infralution Support

Grant · Guest

Hi,

I would like to use the control as a virtual list view. My data does not support the IList interface. It contains a large number of records, so I can't copy the data to something that support IList. Extremely fast virtual rendering of the data is critical in my application.

The documentation indicates, in reference to Programmatic Data Binding, that:

"...It can also be used to handle binding to data that does not support the IList interface."

Are you able to provide an example or some guidence as to how this is done? I am probably missing something, but it appears you must supply a datasource, and the datasource appears to have to support IList.

Thanks in advance.

Grant Johnson
Advansys Pty Limited
Sydney, Australia

Infralution · Joined: 28 Feb 2005 Posts: 5027

grantjohnson · Joined: 05 Oct 2005 Posts: 2

Thank you for the fast response.

The data source is a 'hit' list supplied via the Lucene search engine. It is a virtual list of hits that are accessed via an index value. It does not implement IList (or any other of the collection interfaces). It pages the first 20 or so hits to improve performance, with subquent hits being pages as requested. Unfortunately, copying the entire result set to something that does support IList will be too expensive. I suspect I will have to go down the path of implementing a 'dummy' IList class that provides minimal implementations of the methods you mentioned.

So to confirm my understanding of the virtualisation model, the object assigned to the DataSource property _must_ implement IList in all situations, even when the programmatic data binding approach is being used?

Thanks again.

Grant Johnson

Infralution · Joined: 28 Feb 2005 Posts: 5027

grantjohnson · Joined: 05 Oct 2005 Posts: 2

Thanks for the additional information, and offer of a phone call. Sorry for the delay in my response - we had to get a beta out ASAP, so it was a case of drop everything. We are now back onto getting the release version available, which will most likely use the Virtual Tree control.

I suspect we probably has enough information to move forward at the moment. Another engineer here has taken ownership of this part of the project, so he may have some questions. We'll let you know how we get on.

Thanks

Grant