At some point, you may want to search a tree view field to find out whether it contains a specific node. There are numerous ways to search tree view fields, and a complete discussion of them is beyond the scope of this manual. The following is the code for the TreeView_Search() function. You can use this code as a starting point for searching tree view fields.
function returns long node_found;
inout anonymous field tree_field. {The tree field to search.}
in long search_node; {The ID of the node to search from.}
in string search_item; {The item to search for.}
if search_node = TV_NODEINVALID then
{The search node is not valid.}
node_found = TV_NODEINVALID;
else
if TreeView_GetNodeLabel(tree_field, search_node) = search_item then
{The search item was found.}
node_found = search_node;
else
{If the search node has children, search them.}
node_found = TreeView_Search(tree_field, TreeView_GetFirstChild (tree_field, search_node), search_item);
if node_found = TV_NODEINVALID then
{There are no children, so search the next sibling.}
node_found = TreeView_Search(tree_field, TreeView_GetNextNode(tree_field, search_node), search_item);
end if;
end if;
end if;
The TreeView_Search() function begins searching the tree at the node specified. If a node having the specific label is found, that node’s ID is returned. Otherwise, a value corresponding to the TV_NODEINVALID constant is returned.
This is a depth-first search, meaning that child nodes are searched before sibling nodes. To make this a breadth-first search, in which sibling nodes are searched before child nodes, simply swap the two shaded sanScript statements in the script above.
This is a depth-first search, meaning that child nodes are searched before sibling nodes. To make this a breadth-first search, in which sibling nodes are searched before child nodes, simply swap the two sanScript statements indicated in the above illustration.
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The TreeView_Search() function is recursive, meaning the function makes calls to itself. Many searching algorithms can be coded more efficiently if recursion is used. |
The following example uses the TreeView_Search() function to search the Houses Tree field for the first node whose label is “Fargo”, beginning with the first root-level node.
local long node_ID;
local boolean result;
node_ID = TreeView_Search('Houses Tree', TreeView_GetRootNode ('Houses Tree'), "Fargo");
{If a node was found, select it.}
if node_ID <> TV_NODEINVALID then
result = TreeView_SetSelectedNode('Houses Tree', node_ID);
end if;