添加顯示和值成員屬性

    private m_valuemember as string    private m_displaymember as string    <category("data")> _    public property valuemember() as string        get            return m_valuemember        end get        set(byval value as string)            m_valuemember = value        end set    end property    <category("data")> _    public property displaymember() as string        get            return m_displaymember        end get        set(byval value as string)            m_displaymember = value        end set    end property

使用 currencymanager 對象

• 訪問數據源的基礎 ilist 對象
• 在數據源中檢索和設置對象字段或屬性，以及
• 使您的控件與同一窗體中的其他數據綁定控件同步。

檢索屬性/字段值

dim mynewleafnode as treeleafnodedim currobject as objectcurrobject = cm.list(currentlistindex)if me.displaymember <> "" andalso me.valuemember <> "" then    ' 添加葉節點？    dim pdvalue as system.componentmodel.propertydescriptor    dim pddisplay as system.componentmodel.propertydescriptor    pdvalue = cm.getitemproperties()(me.valuemember)    pddisplay = cm.getitemproperties()(me.displaymember)    mynewleafnode = _    new treeleafnode(cstr(pddisplay.getvalue(currobject)), _          currobject, _          pdvalue.getvalue(currobject), _          currentlistindex)

保持數據綁定控件同步

protected overrides sub onafterselect _ (byval e as system.windows.forms.treevieweventargs)    dim tln as treeleafnode    if typeof e.node is treegroupnode then        tln = findfirstleafnode(e.node)        dim groupargs as new grouptreevieweventargs(e)        raiseevent aftergroupselect(groupargs)    elseif typeof e.node is treeleafnode then        dim leafargs as new leaftreevieweventargs(e)        raiseevent afterleafselect(leafargs)        tln = ctype(e.node, treeleafnode)    end if    if not tln is nothing then        if cm.position <> tln.position then            cm.position = tln.position        end if    end if    mybase.onafterselect(e)end sub

private function findfirstleafnode(byval currnode as treenode) _        as treeleafnode    if typeof currnode is treeleafnode then        return ctype(currnode, treeleafnode)    else        if currnode.nodes.count > 0 then            return findfirstleafnode(currnode.nodes(0))        else            return nothing        end if    end ifend function

private sub cm_positionchanged(byval sender as object, _    byval e as system.eventargs) handles cm.positionchanged    dim tln as treeleafnode    if typeof me.selectednode is treeleafnode then        tln = ctype(me.selectednode, treeleafnode)    else        tln = findfirstleafnode(me.selectednode)    end if    if tln.position <> cm.position then        me.selectednode = findnodebyposition(cm.position)    end ifend subprivate overloads function findnodebyposition(byval index as integer) _        as treenode    return findnodebyposition(index, me.nodes)end functionprivate overloads function findnodebyposition(byval index as integer, _    byval nodestosearch as treenodecollection) as treenode    dim i as integer = 0    dim currnode as treenode    dim tln as treeleafnode    do while i < nodestosearch.count        currnode = nodestosearch(i)        i += 1        if typeof currnode is treeleafnode then            tln = ctype(currnode, treeleafnode)            if tln.position = index then                return currnode            end if        else            currnode = findnodebyposition(index, currnode.nodes)            if not currnode is nothing then                return currnode            end if        end if    loop    return nothingend function

將 datasource 轉變為樹

管理組

private treegroups as new arraylist()public sub removegroup(byval group as group)    if not treegroups.contains(group) then        treegroups.remove(group)        groupingchanged()    end ifend subpublic overloads sub addgroup(byval group as group)    try        treegroups.add(group)        groupingchanged()    catch    end tryend subpublic overloads sub addgroup(byval name as string, _        byval groupby as string, _        byval displaymember as string, _        byval valuemember as string, _        byval imageindex as integer, _        byval selectedimageindex as integer)    dim mynewgroup as new group(name, groupby, _        displaymember, valuemember, _        imageindex, selectedimageindex)    me.addgroup(mynewgroup)end subpublic function getgroups() as group()    return ctype(treegroups.toarray(gettype(group)), group())end function

生成樹

自定義 treeview 事件

public event beforegroupselect _    (byval sender as object, byval e as grouptreeviewcanceleventargs)public event aftergroupselect _    (byval sender as object, byval e as grouptreevieweventargs)public event beforeleafselect _    (byval sender as object, byval e as leaftreeviewcanceleventargs)public event afterleafselect _    (byval sender as object, byval e as leaftreevieweventargs)protected overrides sub onbeforeselect _    (byval e as system.windows.forms.treeviewcanceleventargs)    if typeof e.node is treegroupnode then        dim groupargs as new grouptreeviewcanceleventargs(e)        raiseevent beforegroupselect(cobj(me), groupargs)    elseif typeof e.node is treeleafnode then        dim leafargs as new leaftreeviewcanceleventargs(e)        raiseevent beforeleafselect(cobj(me), leafargs)    end if    mybase.onbeforeselect(e)end subprotected overrides sub onafterselect _    (byval e as system.windows.forms.treevieweventargs)    dim tln as treeleafnode    if typeof e.node is treegroupnode then        tln = findfirstleafnode(e.node)        dim groupargs as new grouptreevieweventargs(e)        raiseevent aftergroupselect(cobj(me), groupargs)    elseif typeof e.node is treeleafnode then        dim leafargs as new leaftreevieweventargs(e)        raiseevent afterleafselect(cobj(me), leafargs)        tln = ctype(e.node, treeleafnode)    end if    if not tln is nothing then        if cm.position <> tln.position then            cm.position = tln.position        end if    end if    mybase.onafterselect(e)end sub

示例應用程序

注意：本示例應用程序（名為“thesample”）包含在本文的下載中。

小結