Collapsing/Expanding a TreeView control programmatically

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Collapsing/Expanding a TreeView programmatically
Example

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Collapsing/Expanding a TreeView control programmatically

Collapsing/Expanding a TreeView programmatically

To collapse a TreeView control through programming use TreeCollapse.
To expand a TreeView through programming, use TreeListItem with a specific local procedure.

Note: To efficiently populate a TreeView control, you can use the AddChildDelayed property on the rows of the control. This property is used to define the procedure that will be run to populate the level to br expanded. Child nodes are only retrieved and populated on demand.

Example

The following codes are used to:

initialize a TreeView control.
expand part of the TreeView control.
collapse the TreeView control.

Initialize the TreeView control programmatically:

TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert", "CAKE-.BMP", "CAKE-.BMP")
TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert" + TAB + "Ice cream")
TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert" + TAB + "Ice cream" + ...
		TAB + "Vanilla", "NEXT5-.BMP")
TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert" + TAB + "Ice cream" + ...
		TAB + "Strawberry", "NEXT5-.BMP")
TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert" + TAB + "Ice cream" + ...
		TAB + "Chocolate", "NEXT5-.BMP")
TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert" + TAB + "Cup")
TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert" + TAB + "Cup" + ...
		TAB + "Banana Split", "NEXT5-.BMP")
TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert" + TAB + "Cup" + ...
		TAB + "Cherry Garcia", "NEXT5-.BMP")
TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert" + TAB + "Cup" + ...
		TAB + "Colonel", "NEXT5-.BMP")
TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert" + TAB + "Apple pie")
TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert" + TAB + "Apple pie" + ...
		TAB + "with whipped cream", "NEXT5-.BMP")
TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert" + TAB + "Apple pie" + ...
		TAB + "with apple brandy", "NEXT5-.BMP")
TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert" + TAB + "Crème brûlée", "NEXT5-.BMP")
TreeAdd(TREE_TVRecipe, "Recipe" + TAB + "Dessert" + TAB + "Meringue with cream", "NEXT5-.BMP")

Expand all elements. The "ExpandAll" procedure is called for each "child" element found. This procedure expands all the collapsed "child" nodes of the "Dessert" node.

// Lists the "children" of "Desserts" node in "TREE_TVRecipe" treeview
// The "ExpandAll" procedure is called
// for each "child" of "Desserts" node found
Res = TreeListItem(TREE_TVRecipe, "Recipe" + TAB + "Dessert", "ExpandAll")

// Local procedure named "ExpandAll"
// This procedure expands all the collapsed "child" nodes of the "Desserts" node
PROCEDURE ExpandAll(TREE_TVRecipe, ChildPath, ChildFound, Level, Pointer)
// Is the element found a leaf?
IF TreeTypeItem(TREE_TVRecipe, ChildPath + ChildFound) = tvLeaf THEN
	RETURN  // Back to TreeListItem
ELSE
	// Is the element found collapsed?
	IF TreeStatus(TREE_TVRecipe, ChildPath + ChildFound) = tvCollapse THEN
		TreeExpand(TREE_TVRecipe, ChildPath + ChildFound)
	END
END

Collapse the "Dessert" node.

// Collapses the "Desserts" node in the "TREE_TVRecipe" control
Res = TreeCollapse(TREE_TVRecipe, "Recipe" + TAB + "Dessert")