SAS/AF Software: Class Dictionary

Using the Tree View Control

The Tree View Control enables you to create a hierarchical list of different text elements, or nodes.

The Tree View control is made up of a series of individual nodes. Nodes can contain both a bitmap and a text label. The first node in the tree is referred to as the root node. All other nodes are children of this node. Each node, including the root node, is defined by an SCL list. The SCL list can contain the following items:

text the text of the node.

iconOpen the icon number used when the node is expanded. The default is CATOPEN (#317).

iconClosed the icon number used when the node is collapsed. The default is SASCAT (#340).

showChildren NO (the default) means that the tree is not expanded if there is a child list. YES means that the tree is expanded if there is a child list.

expandable YES (the default) means that the node can be expanded. NO means that the node cannot be expanded.

children an SCL list identifier that contains the child nodes.

Note: When establishing nodes on a Tree View control, your FRAME SCL must use the _addNodes method. The _addNodes method takes specific parameters, as shown in the previous example.

The first parameter indicates the start node ID. Specifying zero indicates that the items are to be added to the root node. The second parameter indicates the SCL list to add. The third parameter indicates where to add the items in relationship to the specified start node. Valid values are firstchild, lastchild, before, and after. [cautionend]

When to use the Tree View Control

Use the Tree View control when you want to provide users with a view of hierarchical information (which may or may not be expandable). Typically, the Tree View control is used in conjunction with other controls to display the information selected within a tree.

Example

The Tree View control is unavailable in the Components window by default, so you must locate the Tree View class in the Explorer window and then drag and drop it onto a frame to instantiate the class.

Note: The tree portion of a Tree View control is only visible at run-time. [cautionend]

The following example creates a simple tree view control that has a root node and two sub-nodes:

From the Explorer window, select SASHELP.CLASSES.
Select Treeview_c from the list of classes.
Drag and drop the Treeview_c class onto a frame.
Add the following SCL to the INIT section of the FRAME SCL for the frame that contains the tree view control:

/* Copyright (c) 1999 by SAS Institute Inc., Cary, NC USA */

INIT:
  treeList = makelist();
  rootList = makelist();
  rc = insertc(rootList, 'Tree Root Node', -1, 'text');
  RC = insertc(rootList, 'Yes', -1, 'children');
  
  rootChildren=makelist();
  rc = insertl(rootList, rootChildren, -1, 'children');

  node1=makelist();
  rc = insertc(node1, 'Node 1', -1, 'text');
  rc = insertn(node1, 610, -1, 'iconClosed');

  rc=insertl(rootChildren, node1, -1);

  node2=makelist();
  rc = insertc(node1, 'Node 2', -1, 'text');
  rc = insertc(node1, 611, -1, 'iconClosed');

  rc=insertl(rootChildren, node2, -1);

 rc = insertl(treeList,rootList,--1);
 call putlist(treeList, 'List to Create Tree View', 0);
 treeView1._addNodes(0, treeList, 'firstchild');
return;

TERM:
  rc = dellist(treeList, 'y');
return;

The following example creates a Tree View control with a root node, three branches, and four nodes for each branch. Selecting any node causes the text of that node to appear in a Text Entry control.

Create a frame and add a Text Entry control.
From the Explorer window, select SASHELP.CLASSES.
Select Treeview_c from the list of classes.
Drag and drop the Treeview_c class onto the frame.
Add the following FRAME SCL:

/* Copyright (c) 1999 by SAS Institute Inc., Cary, NC USA */

rc=rc;

dcl sashelp.classes.treenode_c.class currentNode,
      string currentNodeText;

INIT: 
 /* Make the main tree list. */
 treeList = makelist();

 /* Make the root node list. */
 rootList = makelist();
 rc = insertc(rootList, 'Tree Root Node', -1, 'text');
 rc = insertn(rootList, 590, -1, 'iconOpen'); 
 rc = insertn(rootList, 590, -1, 'iconClosed');
 rc = insertc(rootList, 'Yes', -1, 'showChildren');
 rc = insertc(rootList, 'Yes', -1, 'expandable');

/* Add a list in the root node named CHILDREN to hold child nodes. */
 rootChildrenList = makelist();
 rc = insertl(rootList, rootChildrenList, -1, 'CHILDREN');
 numberOfChildren = 3;
 numberOfLeafs = 4;

do i = 1 to numberOfChildren;
   dcl string numAsChar;
   numAsChar = trim(left(putn(i, 'BEST.')));

   /* Make the branch node */
   branchList = makelist();
   rc = insertc(branchList, 'Branch '||numAsChar, -1, 'text');
   rc = insertc(branchList, 590, -1, 'iconOpen');
   rc = insertc(branchList, 590, -1, 'iconClosed');

   /* showChildren = Yes means it is expanded if it has a child list
                     No means it is not if it has a child list */

   rem = mod(i, 2);
   if rem = 0 then
      rc = insertc(branchList, 'No', --1, 'showChildren');
   else
      rc = insertc(branchList, 'Yes', --1, 'showChildren');

   /* Add a list in this branch node named CHILDREN to hold its child node */
   branchChildren = makelist();
   rc = insertc(branchList, branchChildren, -1, 'CHILDREN');

   do j = 1 to numberOfLeafs;
      numAsChar = trim(left(putn(j, 'Best.')));
      leafList = makelist();

      /* add correct values for Attributes node on the list */
      rc = insertc(leafList, 'Leaf  '||numAsChar, -1, 'text');
      rem = mod(j, 4);
      if rem = 1 then icon = 593;
      else if rem = 2 then icon = 601;
      else if rem = 3 then icon = 595;
      else icon = 597;
      rc = insertn(leafList, icon, -1, 'iconOpen');
      rc = insertn(leafList, icon, -1, 'iconClosed');
      rc = insertl(branchChildren, leafList, -1);
   end; /*do while j */

   rc = insertl(rootChildrenList, branchList, -1);
 end; /* do while i */

 /* Wrapper needed around the root list for adding the nodes. */
 rc = insertl(treeList, rootList, -1);

 /* _addNodes 1st parm = startnode with 0 being add a new root as well.
              2nd parm = list to add.
              3rd parm = where to add = 'firstchild', 'lastchild', 'before', 'after'
 */
 treeView1._addNodes(0, treeList, 'firstchild');
 call putlist(treeList, 'Tree View List', 0);
 rc = dellist(treeList, 'Y');
return;


TREEVIEW1:
   /* If there is a current node then we set its text value in the first text entry. */
   currentNode = treeview1.selectedNode;
   if currentNode then do;
      currentNodeText = currentNode.text;
      if currentNodeText ne textEntry1.text then
         textEntry1.text = currentNodeText;
   end;
return;

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text	the text of the node.
iconOpen	the icon number used when the node is expanded. The default is CATOPEN (#317).
iconClosed	the icon number used when the node is collapsed. The default is SASCAT (#340).
showChildren	NO (the default) means that the tree is not expanded if there is a child list. YES means that the tree is expanded if there is a child list.
expandable	YES (the default) means that the node can be expanded. NO means that the node cannot be expanded.
children	an SCL list identifier that contains the child nodes.