彩票走势图

ASPxTreeList全面开发了现存的DevExpress外观和针对ASP.NET的数据管理技术。个别节点的按需载入和回叫支持等特点保证方案既优质又有效。在操作中，更新时控件不必传输整个树结构。ASPxTreeList十分智能，它能够确定那部分树结构需要更新，只从服务器中请求少量记录，更快地进行用户交互。

ASPxTreeList-存取和操作数据

四种数据访问选项
为了方便您显示数据，ASPxTreeList提供下列数据绑定选项：

• 非绑定模式
  您可以采用特别的设计方法，用代码构建需求的树形结构

• 动态节点载入
  您可以依您的选择在树中只填入基层代码。尝试用下代节点扩展上代节点可以引发事件，在这里指定需要显示的下代节点。这个方法为巨量资料集提供了重要的绩效收益。

• 绑定到一个分层次的数据源                                                                                                                                 如果您绑定到一个分层次的数据源，如Site Map，控件将自动地建立相应的树。

• 绑定到一个标准的数源
  当绑定到一个标准数据源时，您需要两个服务域来建立树。一个服务域指定某记录的特定ID,另一个指定上代记录的ID。

数据排序
为了方便定位控件中的记录，ASPxTreeList允许你排序无限量行的节点。

正如您所愿，终端用户只需点击数据列标题，便可轻松地开始排列操作。

数据汇总
如果你的web应用程序要求分析数据，ASPxTreeList的数据汇总功能可以让你把重点放在总数，而不是处理单个记录。您可以总结所有记录的数据或者只总结具有共同祖先的记录数据。在这两种情况中，都有5个内建功能为您服务，您也可以使用专门的设计项目手动总结数据。合计结果显示在控件的页脚或分组页脚。请注意，每一行并没有局限只做一个总结，您可以按照自身需要做任意多个总结。

条件格式化
为强调重要的数据，更好的显示不同的值，你可以使用条件格式化。使用这个特性，全部记录或单个元素都可以依据他们所包含的数据进行格式化。

最简单的使用情景是强调具有特定值或上下限值的记录或元素。除此之外，您还可以申请“彩色表”。这就意味着元素将会使用相同颜色的不同色调，用小数字表示亮色调，大数字表示暗色调。

ASPxTreeList-布局和导航特性
以下为您展示ASPxTreeList的一些导航和布局定制特性。

焦点行和选择行
您能够启用焦点行特性来显示最后一次点击的节点。当TreeView用做导航目的时这个功能非常有用...显示终端用户的当前位置。当您在单独的控件中必须显示代码细节时，此功能可以和数据浏览树并用。例如，它可以在显示论坛消息时使用..强调目前正在显示其细节的代码。

多节点选择也是ASPxTreeList内建的特征。您可以启用行中的选择复选框，显示选择所有表头的复选框。

数据分页
假如你的树包含许多记录，你能够分割数据为多页，这样可以有效使用页面空间，提高页面显示速度。ASPxTreeList内建ASPxPager控件允许你通过AJAX callbacks导航页面。

自定义窗口（字段选择器）
假如最终用户需要临时隐藏列或使隐藏的列显示，您能够启用Microsoft Outlook风格的字段选择窗口。最终用户简单地拖字段到窗口来隐藏它们，拖回列表头又可显示它们。

节点预览
为美观地显示memo字段，您可以使用ASPxTreeList的内建节点预览特性。例如您想使用控件建立一个网络论坛，此特性可以帮助您预览一个讨论引线的个人信息。

The ASPxTreeList fully exploits existing DevExpress appearance and data management technologies for ASP.NET. Features such as on-demand loading of individual nodes and callback support ensure that the solutions you build are both elegant and effective. In our implementation, the control never needs to transmit the entire tree structure when being updated. The ASPxTreeList is smart enough to determine which portion of the tree to be renewed and only requests a few records from the server, making user interaction lightning fast.

ASPxTreeList - Access and Manipulate Data

Four Data Access Options

To ensure that your data can be easily displayed within the ASPxTreeList, we provide the following data binding options:

• Unbound Mode
  You can build the desired tree structure in code using specially designed methods.
• Dinamic Node Loading
  At your option, you can populate only root-level nodes within the tree. Attempts to expand parent nodes with children will raise an event wherein you can specify the child nodes to be displayed. This approach offers significant performance gains against large datasets.
• Bind to a Hierarchical Data Source
  If you bind to a hierarchical data source, such as a site map, the control will automatically build the corresponding tree.
• Bind to a Standard Data Source
  When binding to a standard data source, you need to have two service fields to build a tree. One should specify a record's unique ID and the other should specify the parent record's ID.

Data Sorting

To make it easier to locate records within the control, the ASPxTreeList allows you to sort nodes against an unlimited number of columns.

As you might expect, end-users can easily initiate sort operations by simply clicking column headers.

Data Summaries

If your web application requires data analysis, the data summary feature of the ASPxTreeList allows you to focus on the overall numbers instead of having to deal with individual records. You can either summarize data across all records or only those records with a common parent. In both instances, five built-in functions are at your service or you can manually summarize values using a specially designed event. The aggregate result is displayed within the control's footer or group footer. And note that you aren't limited to a single summary per column - you can calculate as many summaries as needed.

Conditional Formatting

To highlight important data or better indicate differences between values, you can use Conditional Formatting. With this feature, entire records or individual cells can be formatted depending upon the data they contain.

The simplest use scenario is to highlight records or cells that have a particular value or that have values above or below a particular limit. Beyond these, you can also apply a "color map". This means that cells will use shades of the same color - lighter shades for smaller numbers and darker shades for higher numbers.

ASPxTreeList - Layout and Navigation Features

The following are just a few of the navigation and layout customization features available to you within the ASPxTreeList.

Focused and Selected Rows

You can enable the focused row feature to indicate the last clicked tree node. This is useful when using the Treeview for navigation purposes...indicating the end-user's current position. It can also be used with data-browser trees when you must display node details in a separate control. For instance, it can be used when displaying forum messages...highlighting the node whose details are currently displayed.

Multi-node selection is also a built-in feature of the ASPxTreeList. By toggling a single option, you can enable selection checkboxes within rows and display a Select All check box within the header panel.

Data Paging

If your tree contains many records, you can split data across multiple pages and thus guarantee a more efficient use of page space and faster initial page rendering. If you do so, the ASPxTreeList displays a built-in ASPxPager control allowing you to navigate to the required page via AJAX callbacks.

Customization Window (Field Chooser)

If end-users need to temporarily hide columns or make hidden columns visible, you can enable a Microsoft Outlook style Field Chooser window. End-users can simply drag fields to the window to hide them and then drag them back to the column header panel to make them visible again.

Node Preview Sections

To elegantly display memo fields, you can use the ASPxTreeList's built-in node preview feature. For instance, if you use the control to create a web forum, this feature allows you to preview individual messages within a discussion thread.