此主题描述了如何在gridcontrol中的视图模型和显示定义总计和分组统计
在视图模型中指定统计
1、创建 SummaryItemType 枚举你想要在GridControl中显示的统计类型：
public enum SummaryItemType { Max, Count, None }2、创建一个grid统计描述类
public class Summary : BindableBase {public Summary(SummaryItemType type, string fieldname) {Type = type;FieldName = fieldname;}public SummaryItemType Type { get; }public string FieldName { get; }
}3、在视图模型中指定合计和分组统计集合
public class CustomersViewModel : ViewModelBase {public CustomersViewModel() {// ...TotalSummary = new ObservableCollection<Summary>() {new Summary(SummaryItemType.Count, nameof(Customer.Name)),new Summary(SummaryItemType.Max, nameof(Customer.Visits))};GroupSummary = new ObservableCollection<Summary>() {new Summary(SummaryItemType.Count, nameof(Customer.Name))};}// ...public ObservableCollection<Summary> TotalSummary { get; }public ObservableCollection<Summary> GroupSummary { get; }
}如果你需要GridControl引用在TotalSummary和GroupSummary集合中的改变，这些集合必须实现INotifyCollectionChanged 接口
创建统计模板
1、指定一个统计类型（Min,Max,Count），设置SummaryItemBase.SummaryType属性到SummaryItemType枚举值。创建ObjectToObjectConverter来映射SummaryItemType枚举值到SummaryItemType枚举值：
<Window ... xmlns:dxmvvm="http://schemas.devexpress.com/winfx/2008/xaml/mvvm"><Window.Resources><dxmvvm:ObjectToObjectConverter x:Key="SummaryTypeConverter"><dxmvvm:MapItem Source="Max" Target="Max" /><dxmvvm:MapItem Source="Count" Target="Count" /><dxmvvm:MapItem Source="None" Target="None" /></dxmvvm:ObjectToObjectConverter></Window.Resources><!-- ... -->
</Window>2、创建一个模板生成统计
使用SummaryTypeConverter去指定Converter参数对于SummaryItemBase.SummaryType属性
使用DependencyObjectExtensions.DataContext附加属性当你绑定到GridControl统计属性。这个附加的属性同步数据更新束缚属性提高grid性能：
<Window.Resources><DataTemplate x:Key="SummaryTemplate"><ContentControl><dxg:GridSummaryItem FieldName="{Binding Path=(dxci:DependencyObjectExtensions.DataContext).FieldName, RelativeSource={RelativeSource Self}}"SummaryType="{Binding Path=(dxci:DependencyObjectExtensions.DataContext).Type, RelativeSource={RelativeSource Self}, Converter={StaticResource SummaryTypeConverter}}"/></ContentControl></DataTemplate>
</Window.Resources>在GridControl中显示视图模型统计
1、绑定TotalSummarySource和GroupSummarySource属性到总计和分组统计集合
2、设置TotalSummaryGeneratorTemplate和GroupSummaryGeneratorTemplate属性到模板生成统计
3、设置DataViewBase.TotalSummaryPosition属性到Top和Bottom显示Total Summary Panel
<dxg:GridControl ...TotalSummarySource="{Binding TotalSummary}"GroupSummarySource="{Binding GroupSummary}"TotalSummaryGeneratorTemplate="{StaticResource SummaryTemplate}"GroupSummaryGeneratorTemplate="{StaticResource SummaryTemplate}"><dxg:GridControl.View><dxg:TableView TotalSummaryPosition="Bottom"/></dxg:GridControl.View>
</dxg:GridControl>
