John,
We use virtual tree view extensively, for tree views, as a grid and as a property editor. Contrary to what you might have heard, it is not hard to learn. The only thing that you will need to get your head around is the fact that it is virtual, ie., it does not contain any data. The data structures only contain the data hierarchy. The tree view gets the caption, icon, colour, etc. by firing events and you handle those events and provide the appropriate information.
Each node on the tree is represented by a record structure - the detail of which mostly do not concern the programmer. On the structure, there is, by default, a 4 byte pointer, which you can use to point to the actual data. You can tell the tree to extend the structure to store mre data, but IMHO, it is better to just use the pointer to reference an object where you would store all the data.
The construction of the tree nodes is also dynamic, meaning, the tree will ask you to construct the nodes, and it will only ask you for the nodes that it needs to display. For example, if you have a node with child nodes; as long as the parent node has not yet been expanded, the child nodes will not be created.
By using events to get data to display, you get things like dynamic updating of data across multiple trees when the data source has changed pretty much for free.
Using the events is really easy. For example, the event to get the text of a node will pass as a parameter, a reference to the node's record structure. You would then use this to dreference your object and return the text that should be displayed on the tree.
HTH, Dennis.
From: "John Bird" <[EMAIL PROTECTED]> Date: Tue, 13 Sep 2005 16:16:19 +1200 Anyone got references other than the Web Site for reading/manual stuff for Virtual Tree View.. Particularly using as a grid. What it can do looks terrific, found it so far quite hard to learn. John B _______________________________________________ Delphi mailing list [email protected] http://ns3.123.co.nz/mailman/listinfo/delphi
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