未綁定數(shù)據(jù)源
UnboundDataSource組件設(shè)計(jì)用于在編譯時(shí)沒有強(qiáng)類型數(shù)據(jù)集可用的非常規(guī)綁定場景。
提示：UnboundDataSource是數(shù)據(jù)感知控件和數(shù)據(jù)源之間的一層。
下圖展示了UnboundDataSource組件的基本功能。
初始化未綁定數(shù)據(jù)源
提示：項(xiàng)目源向?qū)г谥胁豢捎谩?
項(xiàng)目源向?qū)菍evExpress數(shù)據(jù)感知控件綁定到任何受支持的數(shù)據(jù)源類型的最方便的方法。在本文中，以綁定數(shù)據(jù)網(wǎng)格為例。
1.通過單擊GridControl右上角的圖標(biāo)打開GridControl的Smart Tag面板選擇Items Source Wizard。
2.選擇“Unbound Data Source”選項(xiàng)并單擊 Next。
3.選擇“Simple Binding”選項(xiàng)并單擊 Next。
4.Row Count字段允許您指定GridControl將顯示的記錄數(shù)。
單擊Finish后，將生成以下XAML。
XAML：
<Window ...
xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid">
<Window.Resources>
<dx:UnboundDataSource x:Key="UnboundDataSource" Count="100"/>
</Window.Resources>
<Grid>
<dxg:GridControl AutoGenerateColumns="AddNew" EnableSmartColumnsGeneration="True" ItemsSource="{Binding Data, Source={StaticResource UnboundDataSource}}">
<dxg:GridControl.View>
<dxg:TableView AllowPerPixelScrolling="True" TotalSummaryPosition="Bottom"/>
</dxg:GridControl.View>
</dxg:GridControl>
</Grid>
</Window>
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映射UnboundDataSource數(shù)據(jù)
要將UnboundDataSource映射到數(shù)據(jù)，請使用UnboundDataSourceProperty對(duì)象填充UnboundDataSource.Properties集合，每個(gè)UnboundDataSourceProperty對(duì)象標(biāo)識(shí)一個(gè)數(shù)據(jù)源字段。
下表列出了允許您將UnboundDataSourceProperty對(duì)象與數(shù)據(jù)源字段關(guān)聯(lián)的屬性。
| 屬性 | 描述 |
|---|---|
| UnboundDataSourceProperty.Name | 指定由當(dāng)前UnboundDataSourceProperty表示的屬性的名稱。 |
| UnboundDataSourceProperty.DisplayName | 指定屬性的顯示名稱。 |
| UnboundDataSourceProperty.PropertyType | 指定屬性的類型 |
下面的示例演示了UnboundDataSource，它表示一個(gè)具有兩列不同類型的表，Numbers列值使用 in-place SpinEdit編輯器編輯。
XAML：
<Window ...
xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid">
<Window.Resources>
<dx:UnboundDataSource x:Key="UnboundDataSource" Count="100">
<dx:UnboundDataSource.Properties>
<dx:UnboundDataSourceProperty DisplayName="ID" Name="Numbers" PropertyType="{x:Type sys:Int32}"/>
<!-- UnboundDataSourceProperty.DisplayName property specifies the default column header -->
<dx:UnboundDataSourceProperty DisplayName="String Values" Name="Strings" PropertyType="{x:Type sys:String}"/>
</dx:UnboundDataSource.Properties>
</dx:UnboundDataSource>
</Window.Resources>
<Grid>
<dxg:GridControl AutoGenerateColumns="AddNew" EnableSmartColumnsGeneration="True" ItemsSource="{Binding Data, Source={StaticResource UnboundDataSource}}">
<!-- UnboundSourceProperty.Name value is used to specify the field name -->
<dxg:GridColumn FieldName="Numbers" Header="ID">
<dxg:GridColumn.EditSettings>
<dxe:SpinEditSettings/>
</dxg:GridColumn.EditSettings>
</dxg:GridColumn>
<dxg:GridControl.View>
<dxg:TableView AllowPerPixelScrolling="True" TotalSummaryPosition="Bottom"/>
</dxg:GridControl.View>
</dxg:GridControl>
</Grid>
</Window>
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數(shù)據(jù)同步
UnboundDataSource要求您手動(dòng)處理數(shù)據(jù)操作，可以通過處理以下事件來同步GridControl和數(shù)據(jù)源。
| 事件 | 描述 |
|---|---|
| UnboundDataSource.ValueNeeded | 每次從數(shù)據(jù)源中提取項(xiàng)時(shí)發(fā)生。 |
| UnboundDataSource.ValuePushed | 每次將修改的數(shù)據(jù)推送到數(shù)據(jù)源時(shí)發(fā)生。 |
提示：當(dāng)初始填充數(shù)據(jù)感知控件時(shí)，UnboundDataSource.ValueNeeded事件在每次從數(shù)據(jù)源提取值時(shí)觸發(fā)。
例如，如果將行數(shù)設(shè)置為10，并且UnboundDataSource.Properties集合包含2個(gè)UnboundDataSourceProperty對(duì)象，則UnboundDataSource.ValueNeeded事件將發(fā)生20次。
下面的示例演示鏈接到包含示例數(shù)據(jù)的ViewModel類的UnboundDataSource。
C#：
public class ViewModel {
//Each data cell is identified by a list index and key value.
//The key is a string that specifies the column name.
public List<Dictionary<string, object>> Data { get; set; }
public ViewModel() {
CreateList();
}
//Populates the list with sample data
void CreateList() {
Data = new List<Dictionary<string, object>>();
//Creates 1000 rows
for (int i = 0; i < 1000; i++) {
Data.Add(CreateDictionary(i));
}
}
//Each dictionary object represents a data row.
//Each dictionary item represents a cell value. It stores a string (column name) and a value (cell value)
Dictionary<string,object> CreateDictionary(int i) {
Dictionary<string, object> dict = new Dictionary<string, object>();
//Specifies the value in the "Strings" column
dict.Add("Strings", "Value" + i.ToString());
//Specifies the value in the "Numbers" column
dict.Add("Numbers", i);
return dict;
}
}
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C#：
public partial class MainWindow : Window {
public MainWindow() {
vm = new ViewModel();
DataContext = vm;
InitializeComponent();
}
//Processes the pull operation
private void UnboundDataSource_ValueNeeded(object sender, DevExpress.Data.UnboundSourceValueNeededEventArgs e) {
var index = e.RowIndex;
if(e.PropertyName == "Strings") {
e.Value = vm.Data[index]["Strings"];
}
if(e.PropertyName == "Numbers") {
e.Value = vm.Data[index]["Numbers"];
}
}
//Processes the push operation
private void UnboundDataSource_ValuePushed(object sender, DevExpress.Data.UnboundSourceValuePushedEventArgs e) {
var index = e.RowIndex;
if(e.PropertyName == "Strings") {
vm.Data[index]["Strings"] = (string)e.Value;
}
if(e.PropertyName == "Numbers") {
vm.Data[index]["Numbers"] = (int)e.Value;
}
}
}
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XAML：
<Window ...
xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid">
<Window.Resources>
<dx:UnboundDataSource x:Key="UnboundDataSource" Count="100" ValueNeeded="UnboundDataSource_ValueNeeded" ValuePushed="UnboundDataSource_ValuePushed">
<dx:UnboundDataSource.Properties>
<dx:UnboundDataSourceProperty DisplayName="ID" Name="Numbers" PropertyType="{x:Type sys:Int32}"/>
<dx:UnboundDataSourceProperty DisplayName="String Values" Name="Strings" PropertyType="{x:Type sys:String}"/>
</dx:UnboundDataSource.Properties>
</dx:UnboundDataSource>
</Window.Resources>
<Grid>
<dxg:GridControl AutoGenerateColumns="AddNew" EnableSmartColumnsGeneration="True" ItemsSource="{Binding Data, Source={StaticResource UnboundDataSource}}">
<dxg:GridControl.View>
<dxg:TableView AllowPerPixelScrolling="True" TotalSummaryPosition="Bottom"/>
</dxg:GridControl.View>
</dxg:GridControl>
</Grid>
</Window>
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下圖展示了結(jié)果：
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