DxTreeViewDataMapping Class
Maps TreeView node properties to data source fields.
Namespace: DevExpress.Blazor
Assembly: DevExpress.Blazor.v21.2.dll
NuGet Package: DevExpress.Blazor
Declaration
public class DxTreeViewDataMapping :
DxTreeViewDataMappingBase
Remarks
The TreeView component supports binding to data. In the bound mode, items from the data source automatically populate TreeView nodes.
Follow the steps below to bind TreeView to data:
Use the Data property to specify a data source. You can use different data types:
- Flat data - a collection of items that are available at one level.
- Hierarchical data - a collection of nested nodes.
Add the DataMappings tag to the component’s markup.
Create the
DxTreeViewDataMapping
instance and map node properties (HasChildren, IconCssClass, and so on) to data source fields. Mappings are used to link the TreeView data model to the data source.Flat data - the Key and ParentKey properties are required. If the TreeView’s structure consists of only one level, you can omit these properties.
Hierarchical data - the Children property is required.
You can also create multiple
DxTreeViewDataMapping
instances to specify different mappings for different node levels. Use the Level property to specify the node level for which data mappings are applied.
Flat Data
The code below binds the TreeView to the collection of flat data items. It specifies mappings for the Text, Key, and ParentKey properties.
@if(Data == null) {
<p><em>Loading...</em></p>
}
else {
<div class="cw-320">
<DxTreeView Data="@Data">
<DataMappings>
<DxTreeViewDataMapping Text="Name"
Key="Id"
ParentKey="CategoryId" />
</DataMappings>
</DxTreeView>
</div>
}
@code {
List<FlatDataItem> Data { get; set; }
protected override void OnInitialized() {
IEnumerable<ProductFlat> products = ProductData.Products;
IEnumerable<ProductCategory> productSubcategories = ProductData.Categories;
Data = new List<FlatDataItem>(Enum.GetValues<ProductCategoryMain>().Select(i => new FlatDataItem() { Name = i.ToString(), Id = i }));
Data.AddRange(products.Select(i => new FlatDataItem() { Name = i.ProductName, Id = i.Id, CategoryId = i.ProductCategoryId }));
Data.AddRange(productSubcategories.Select(i => new FlatDataItem() { Name = i.Subcategory, Id = i.SubcategoryID, CategoryId = i.Category }));
}
}
Hierarchical Data
The code below binds the TreeView to the collection of ChemicalElementGroup objects. Each object can have child objects. The code specifies the Children and Text mappings to adjust the TreeView data model to the specified data source.
<DxTreeView Data="@ChemicalElements.Groups">
<DataMappings>
<DxTreeViewDataMapping Children="Groups"
Text="Name"/>
</DataMappings>
</DxTreeView>