做淘客的网站有哪些,电商怎么做账和报税,做网站需要学会写代码吗,上海市嘉定建设局网站WPF中TreeView.BringIntoView方法的替代方案 周银辉 WPF中TreeView.BringIntoView#xff08;#xff09;方法并不是那么地好用#xff0c;不少时候会没有效果#xff0c;这里有一个替代方案#xff0c;调用SelectItem#xff08;#xff09;方法可以展开并呈现TreeView… WPF中TreeView.BringIntoView方法的替代方案 周银辉 WPF中TreeView.BringIntoView方法并不是那么地好用不少时候会没有效果这里有一个替代方案调用SelectItem方法可以展开并呈现TreeView上指定的Item public static class TreeViewHelper { /// summary /// Expands all children of a TreeView /// /summary /// param nametreeViewThe TreeView whose children will be expanded/param public static void ExpandAll(this TreeView treeView) { ExpandSubContainers(treeView); } /// summary /// Expands all children of a TreeView or TreeViewItem /// /summary /// param nameparentContainerThe TreeView or TreeViewItem containing the children to expand/param private static void ExpandSubContainers(ItemsControl parentContainer) { foreach (Object item in parentContainer.Items) { TreeViewItem currentContainer parentContainer.ItemContainerGenerator.ContainerFromItem(item) as TreeViewItem; if (currentContainer ! null currentContainer.Items.Count 0) { //expand the item currentContainer.IsExpanded true; //if the items children are not generated, they must be expanded if (currentContainer.ItemContainerGenerator.Status ! GeneratorStatus.ContainersGenerated) { //store the event handler in a variable so we can remove it (in the handler itself) EventHandler eh null; eh new EventHandler(delegate { //once the children have been generated, expand those childrens children then remove the event handler if (currentContainer.ItemContainerGenerator.Status GeneratorStatus.ContainersGenerated) { ExpandSubContainers(currentContainer); currentContainer.ItemContainerGenerator.StatusChanged - eh; } }); currentContainer.ItemContainerGenerator.StatusChanged eh; } else //otherwise the children have already been generated, so we can now expand those children { ExpandSubContainers(currentContainer); } } } } /// summary /// Searches a TreeView for the provided object and selects it if found /// /summary /// param nametreeViewThe TreeView containing the item/param /// param nameitemThe item to search and select/param public static void SelectItem(this TreeView treeView, object item) { ExpandAndSelectItem(treeView, item); } /// summary /// Finds the provided object in an ItemsControls children and selects it /// /summary /// param nameparentContainerThe parent container whose children will be searched for the selected item/param /// param nameitemToSelectThe item to select/param /// returnsTrue if the item is found and selected, false otherwise/returns private static bool ExpandAndSelectItem(ItemsControl parentContainer, object itemToSelect) { //check all items at the current level foreach (Object item in parentContainer.Items) { TreeViewItem currentContainer parentContainer.ItemContainerGenerator.ContainerFromItem(item) as TreeViewItem; //if the data item matches the item we want to select, set the corresponding //TreeViewItem IsSelected to true if (item itemToSelect currentContainer ! null) { currentContainer.IsSelected true; currentContainer.BringIntoView(); currentContainer.Focus(); //the item was found return true; } } //if we get to this point, the selected item was not found at the current level, so we must check the children foreach (Object item in parentContainer.Items) { TreeViewItem currentContainer parentContainer.ItemContainerGenerator.ContainerFromItem(item) as TreeViewItem; //if children exist if (currentContainer ! null currentContainer.Items.Count 0) { //keep track of if the TreeViewItem was expanded or not bool wasExpanded currentContainer.IsExpanded; //expand the current TreeViewItem so we can check its child TreeViewItems currentContainer.IsExpanded true; //if the TreeViewItem child containers have not been generated, we must listen to //the StatusChanged event until they are if (currentContainer.ItemContainerGenerator.Status ! GeneratorStatus.ContainersGenerated) { //store the event handler in a variable so we can remove it (in the handler itself) EventHandler eh null; eh new EventHandler(delegate { if (currentContainer.ItemContainerGenerator.Status GeneratorStatus.ContainersGenerated) { if (ExpandAndSelectItem(currentContainer, itemToSelect) false) { //The assumption is that code executing in this EventHandler is the result of the parent not //being expanded since the containers were not generated. //since the itemToSelect was not found in the children, collapse the parent since it was previously collapsed currentContainer.IsExpanded false; } //remove the StatusChanged event handler since we just handled it (we only needed it once) currentContainer.ItemContainerGenerator.StatusChanged - eh; } }); currentContainer.ItemContainerGenerator.StatusChanged eh; } else //otherwise the containers have been generated, so look for item to select in the children { if (ExpandAndSelectItem(currentContainer, itemToSelect) false) { //restore the current TreeViewItems expanded state currentContainer.IsExpanded wasExpanded; } else //otherwise the node was found and selected, so return true { return true; } } } } //no item was found return false; } } 转载于:https://www.cnblogs.com/zhouyinhui/archive/2008/12/22/1360033.html
