In this lesson, you will learn how to provide several customized variants of the same View, and allow an end-user to choose a desired View variant at runtime. Variants can be applied to both List Views and Detail Views. In this lesson, the Contact List View will be used. Two variants of this List View will be constructed via the Module Editor. To switch between these View variants, the special ChangeVariant Action will be used. To add this Action, the ViewVariants module will be referenced in the application.
在本课中，您将学习如何提供同一视图的多个自定义变体，并允许最终用户在运行时选择所需的视图变体。变体可以同时应用于"列表视图"和"详细信息视图"。在本课中，将使用联系人列表视图。此列表视图的两个变体将通过模块编辑器构造。要在这些视图变体之间切换，将使用特殊的更改变量操作。要添加此操作，将在应用程序中引用"查看变体"模块。
Note 注意
Before proceeding, take a moment to review the following lessons.
在继续之前，请花点时间复习以下课程。
- Inherit from the Business Class Library Class (XPO/EF)
- 从商务舱库类 （XPO/EF） 继承
- Change Field Layout and Visibility in a List View
- 在列表视图中更改字段布局和可见性
- Add the View Variants module to your MySolution.Module project. Find the Module.cs (Module.vb) file in the MySolution.Module project displayed in the Solution Explorer, and double-click this file. The Module Designer will be invoked.
In the Toolbox, navigate to the DX.19.2: XAF Modules tab. Drag the ViewVariantsModule item from this tab to the Designer's Required Modules section.
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将"查看变体"模块添加到 MySolution.模块项目中。在解决方案资源管理器中显示的 MySolution.module 项目中查找Module.cs （Module.vb） 文件，然后双击此文件。将调用模块设计器。
在工具箱中，导航到 DX.19.2：XAF 模块选项卡。将"视图Variants模块"项目从此选项卡拖动到"设计器的必需模块"部分。
- Rebuild your solution so that the changes made in the Module Designer are loaded to the Application Model.
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Invoke the Model Editor for the MySolution.Module project. Right-click the Views node and select Add... | ListView.
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重新生成解决方案，以便将模块设计器中所做的更改加载到应用程序模型。
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调用 MySolution.模块项目的模型编辑器。右键单击"查看"节点并选择"添加..." |Listview。
For the new node, set the Id property to "Contact_ListView_AllColumns" and the ModelClass property to "Contact".
对于新节点，将 Id 属性设置为"Contact_ListView_AllColumns"，将 ModelClass 属性设置为"联系人"。
- Right-click the newly created node and select Generate content. Columns will be generated using information on the specified class (BOModel | Contact node) and its ancestors. Leave these columns as is. This List View will represent the complete variant for the Contact List View.
- 右键单击新创建的节点并选择"生成内容"。将使用指定类上的信息生成列（BOModel |联系节点）及其祖先。保持这些列不变。此列表视图将表示联系人列表视图的完整变体。
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Right-click the Views node and select Add... | ListView. For the new node, set the Id property to "Contact_ListView_Varied" and the ModelClass property to "Contact". Do not generate content for the new node.
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右键单击"查看"节点并选择"添加..." |Listview。对于新节点，将 Id 属性设置为"Contact_ListView_Varied"，将 ModelClass 属性设置为"联系人"。不要为新节点生成内容。
Expand the newly added Contact_ListView_Varied node, right-click the Variants child node and select Add... | Variant.
展开新添加的Contact_ListView_Varied节点，右键单击变体子节点并选择"添加..." |变异。
For the new node, set the View property to "Contact_ListView", and set the Id and Caption properties to "Few columns".
对于新节点，将 View 属性设置为"Contact_ListView"，并将 Id 和标题属性设置为"很少列"。
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Right-click the Variants node and select Add... | Variant. For the new node, set the View property to "Contact_ListView_AllColumns", and set the Id and Caption properties to "All columns".
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右键单击变体节点并选择"添加..." |变异。对于新节点，将 View 属性设置为"Contact_ListView_AllColumns"，并将 Id 和标题属性设置为"所有列"。
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Navigate to the NavigationItems | Items | Default | Items | Contact node. Its View property, specifying the View displayed when choosing the Contact navigation item, is "Contact_ListView" by default. Change it to "Contact_ListView_Varied".
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导航到导航项 |项目 |默认值 |项目 |联系节点。默认情况下，其 View 属性（指定选择"联系人"导航项时显示的视图）为"Contact_ListView"。将其更改为"Contact_ListView_Varied"。。
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Run the WinForms or ASP.NET application. Select the Contact item in the navigation control. For the displayed Contact List View, the ChangeVariant Action will be activated. This Action's items represent the view variants specified in the Model Editor.
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运行 WinForms 或ASP.NET应用程序。选择导航控件中的"联系人"项。对于显示的联系人列表视图，将激活"更改变量"操作。此操作的项表示模型编辑器中指定的视图变体。
Note 注意
You can use the Index property to specify the sort order of variants in the ChangeVariant Action drop-down list. Additionally, you can set the Current property of the Variants node to specify the default variant.
可以使用 Index 属性在"更改变体操作"下拉列表中指定变体的排序顺序。此外，还可以设置变体节点的"当前"属性以指定默认变体。
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Optionally, you can add view variants to the navigation control. For this purpose, invoke the Model Editor and set the GenerateRelatedViewVariantsGroup property of the NavigationItems node to true.
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或者，您可以将视图变体添加到导航控件。为此，调用模型编辑器，并将导航项节点的"生成相关视图VariantsGroup"属性设置为 true。
Note 注意
Ensure that the IModelChoiceActionItemChildItemsDisplayStyle.ChildItemsDisplayStyle property of the current navigation group node is set to List (see Change Style of Navigation Items). Otherwise, the view variants will not be added to the navigation control in the WinForms application.
确保 IModelChoiceActionItemItem 显示样式.子项显示当前导航组节点的样式属性设置为"列表"（请参阅更改导航项的样式）。否则，视图变体将不会添加到 WinForms 应用程序中的导航控件中。
As a result, the Contact navigation item will expose child items for each view variant.
因此，"联系人"导航项将公开每个视图变体的子项。
You can see the changes made in this lesson in the Model Editor invoked for the Model.DesignedDiffs.xafml file, located in the Main Demo | MainDemo.Module project. The MainDemo application is installed in %PUBLIC%DocumentsDevExpress Demos 19.2ComponentseXpressApp FrameworkMainDemo by default. The ASP.NET version is available online at http://demos.devexpress.com/XAF/MainDemo/
您可以在本课中为模型调用的模型编辑器中所做的更改。主演示模块项目。主演示应用程序安装在%PUBLIC%DocumentsDevExpress Demos 19.2ComponentseXpressApp FrameworkMainDemo by default. The ASP.NET version is available online at http://demos.devexpress.com/XAF/MainDemo/
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