WPF中TreeView控件的用法

第WPF中TreeView控件的用法在WPF的TreeView使用方式和WinForm下有很大不同，那些展開某節(jié)點、獲取父節(jié)點，判斷某節(jié)點是否被選中等常用的操作在WinForm下都有相關函數(shù)，而在WPF中卻不能輕易實現(xiàn)。

一種常規(guī)的方式是通過MVVM模式來將TreeViewItem節(jié)點中的IsSelect，IsExpanded等屬性來雙向綁定到要顯示的節(jié)點數(shù)據(jù)中，然后直接通過節(jié)點數(shù)據(jù)的屬性來實現(xiàn)相關操作。

但是，有的時候，當我們沒有ViewModel層，但又想像WinFrom那樣直接簡單的獲取或設置這些屬性的時候，該如何辦呢。其實WPF還是提供了類似WinForm中的這些設置的，只不過形式不一樣了而已，但是卻沒WinFrom的那么直觀和方便。CodeProject上就有人將常用函數(shù)總結了一下，寫成了擴展函數(shù)，主要提供如下功能：

publicstaticvoidSelectObject(thisTreeViewtreeView,objectobj)

publicstaticvoidSelectObject(thisTreeViewtreeView,objectobj,boolselected)

publicstaticboolIsObjectSelected(thisTreeViewtreeView,objectobj)

publicstaticboolIsObjectFocused(thisTreeViewtreeView,objectobj)

publicstaticvoidExpandObject(thisTreeViewtreeView,objectobj)

publicstaticvoidExpandObject(thisTreeViewtreeView,objectobj,boolexpanded)

publicstaticboolIsObjectExpanded(thisTreeViewtreeView,objectobj)

publicstaticTreeViewItemGetParentItem(thisTreeViewItemitem)

文章地址如下：WPFTreeViewtools

但是，這里面有一個小bug：當TreeView節(jié)點中使用延遲綁定的時候，根據(jù)數(shù)據(jù)節(jié)點獲取TreeItem會失敗。這里我把它修正了一下，感興趣的朋友可以直接使用我修改后的函數(shù)。

publicstaticclassTreeViewTools

///summary

///ReturnstheTreeViewItemofadataboundobject.

////summary

///paramname="treeView"TreeView/param

///paramname="obj"Databoundobject/param

///returnsTheTreeViewItemofthedataboundobjectornull./returns

publicstaticTreeViewItemGetItemFromObject(thisTreeViewtreeView,objectobj)

DependencyObjectdObject=GetContainerFormObject(treeView,obj);

TreeViewItemtvi=dObjectasTreeViewItem;

while(tvi==null)

dObject=VisualTreeHelper.GetParent(dObject);

tvi=dObjectasTreeViewItem;

returntvi;

catch{}

returnnull;

privatestaticDependencyObjectGetContainerFormObject(ItemsControlitem,objectobj)

if(item==null)

returnnull;

DependencyObjectdObject=null;

dObject=item.ItemContainerGenerator.ContainerFromItem(obj);

if(dObject!=null)

returndObject;

varquery=fromchildIteminitem.Items.Castobject()

letchildControl=item.ItemContainerGenerator.ContainerFromItem(childItem)asItemsControl

selectGetContainerFormObject(childControl,obj);

returnquery.FirstOrDefault(i=i!=null);

///summary

///SelectsadataboundobjectofaTreeView.

////summary

///paramname="treeView"TreeView/param

///paramname="obj"Databoundobject/param

publicstaticvoidSelectObject(thisTreeViewtreeView,objectobj)

treeView.SelectObject(obj,true);

///summary

///SelectsordeselectsadataboundobjectofaTreeView.

////summary

///paramname="treeView"TreeView/param

///paramname="obj"Databoundobject/param

///paramname="selected"selectordeselect/param

publicstaticvoidSelectObject(thisTreeViewtreeView,objectobj,boolselected)

vartvi=treeView.GetItemFromObject(obj);

if(tvi!=null)

tvi.IsSelected=selected;

///summary

///ReturnsifadataboundobjectofaTreeViewisselected.

////summary

///paramname="treeView"TreeView/param

///paramname="obj"Databoundobject/param

///returnsReturnstrueiftheobjectisselected,andfalseifitisnotselectedorobjisnotinthetree./returns

publicstaticboolIsObjectSelected(thisTreeViewtreeView,objectobj)

vartvi=treeView.GetItemFromObject(obj);

if(tvi!=null)

returntvi.IsSelected;

returnfalse;

///summary

///ReturnsifadataboundobjectofaTreeViewisfocused.

////summary

///paramname="treeView"TreeView/param

///paramname="obj"Databoundobject/param

///returnsReturnstrueiftheobjectisfocused,andfalseifitisnotfocusedorobjisnotinthetree./returns

publicstaticboolIsObjectFocused(thisTreeViewtreeView,objectobj)

vartvi=treeView.GetItemFromObject(obj);

if(tvi!=null)

returntvi.IsFocused;

returnfalse;

///summary

///ExpandsadataboundobjectofaTreeView.

////summary

///paramname="treeView"TreeView/param

///paramname="obj"Databoundobject/param

publicstaticvoidExpandObject(thisTreeViewtreeView,objectobj)

treeView.ExpandObject(obj,true);

///summary

///ExpandsorcollapsesadataboundobjectofaTreeView.

////summary

///paramname="treeView"TreeView/param

///paramname="obj"Databoundobject/param

///paramname="expanded"expandorcollapse/param

publicstaticvoidExpandObject(thisTreeViewtreeView,objectobj,boolexpanded)

vartvi=treeView.GetItemFromObject(obj);

if(tvi!=null)

tvi.IsExpanded=expanded;

if(expanded)

//updatelayout,sothatfollowingcallstof.e.SelectObjectonchildnodeswill

//findtheireTreeViewNodes

treeView.UpdateLayout();

///summary

///ReturnsifadoutaboundobjectofaTreeViewisexpanded.

////summary

///paramname="treeView"TreeView/param

///paramname="obj"Databoundobject/param

///returnsReturnstrueiftheobjectisexpanded,andfalseifitiscollapsedorobjisnotinthetree./returns

publicstaticboolIsObjectExpanded(thisTreeViewtreeView,objectobj)

vartvi=treeView.GetItemFromObject(obj);

if(tvi!=null)

returntvi.IsExpanded;

returnfalse;

///summary

///RetunstheparentTreeViewItem.

////summary

///paramname="item"TreeViewItem/param

///returnsParentTreeViewItem/returns

publicstaticTreeViewItemGetParentI