DxTreeListDataColumn.CellDisplayTemplate Property
Specifies a template used to display column cells.
Namespace: DevExpress.Blazor
Assembly: DevExpress.Blazor.v24.2.dll
NuGet Package: DevExpress.Blazor
Declaration
[Parameter]
public RenderFragment<TreeListDataColumnCellDisplayTemplateContext> CellDisplayTemplate { get; set; }Property Value
| Type | Description |
|---|---|
| RenderFragment<TreeListDataColumnCellDisplayTemplateContext> | The column cell template. |
Remarks
The CellDisplayTemplate property allows you to specify custom content and change the appearance of cells in individual columns. To define a common template for cells of all TreeList columns, use the DxTreeList.DataColumnCellDisplayTemplate.
The CellDisplayTemplate property accepts a TreeListDataColumnCellDisplayTemplateContext object as the context parameter. You can use the parameter’s members to get information about a column cell (DataColumn, Value, DisplayText, VisibleIndex). You can also access the TreeList object and use its members to obtain additional information about the TreeList.
The following code snippet displays links to Wikipedia pages:
@inject SpaceObjectDataProvider SpaceObjectDataProvider
<DxTreeList Data="TreeListData" ChildrenFieldName="Satellites">
<Columns>
<DxTreeListDataColumn FieldName="Name" />
<DxTreeListDataColumn FieldName="TypeOfObject" Caption="Type" />
<DxTreeListDataColumn FieldName="Mass10pow21kg" Caption="Mass, kg" DisplayFormat="N2">
<HeaderCaptionTemplate>Mass, 10<sup>21</sup> × kg</HeaderCaptionTemplate>
</DxTreeListDataColumn>
<DxTreeListDataColumn FieldName="MeanRadiusInKM" Caption="Radius, km" DisplayFormat="N2" />
<DxTreeListDataColumn FieldName="Volume10pow9KM3" DisplayFormat="N2">
<HeaderCaptionTemplate>Volume, 10<sup>9</sup> × km<sup>3</sup></HeaderCaptionTemplate>
</DxTreeListDataColumn>
<DxTreeListDataColumn FieldName="SurfaceGravity" DisplayFormat="N2">
<HeaderCaptionTemplate>Gravity, m/s<sup>2</sup></HeaderCaptionTemplate>
</DxTreeListDataColumn>
<DxTreeListDataColumn FieldName="WikiPage" AllowSort="false" Width="90px">
<CellDisplayTemplate><a href="@context.Value">Open Wikipedia</a></CellDisplayTemplate>
</DxTreeListDataColumn>
</Columns>
</DxTreeList>
@code {
object TreeListData { get; set; }
protected override async Task OnInitializedAsync() {
TreeListData = SpaceObjectDataProvider.GenerateData();
}
}
For more information about templates in the TreeList component, refer to the following topic: Templates in Blazor TreeList.
Cell Editing Specifics
During edit operations, the TreeList applies user changes only to the edit model and keeps the data item unchanged. DataItem, DisplayText, and Value context parameters return information about the data item, not the edit model. As a result, values of these properties do not reflect unsaved changes.
When the EditMode is set to CellEdit, only one TreeList cell can be in edit mode while others are in display mode. The CellDisplayTemplate affects contents of cells in display mode, including cells with modified values. To display unsaved changes in the CellDisplayTemplate, use the edit model’s field values instead of properties of the template’s context parameter:
@inject EmployeeTaskService EmployeeTaskService
<DxTreeList Data="TreeListData"
KeyFieldName="Id"
ParentKeyFieldName="ParentId"
EditMode="TreeListEditMode.EditCell"
EditModelSaving="TreeList_EditModelSaving"
DataItemDeleting="TreeList_DataItemDeleting"
CustomizeEditModel="TreeList_CustomizeEditModel">
<Columns>
<DxTreeListCommandColumn EditButtonVisible="false"
CancelButtonVisible="false"
SaveButtonVisible="false" />
<DxTreeListDataColumn FieldName="Name" Caption="Task">
<CellDisplayTemplate Context="displayContext">
@{
string value;
if (displayContext.TreeList.IsEditingRow(displayContext.VisibleIndex)) {
var editModel = (EmployeeTask)displayContext.TreeList.GetEditContext().Model;
value = editModel.Name;
}
else
value = displayContext.DisplayText;
}
<span>@value</span>
</CellDisplayTemplate>
</DxTreeListDataColumn>
<DxTreeListDataColumn FieldName="EmployeeName" />
<DxTreeListDataColumn FieldName="StartDate" />
<DxTreeListDataColumn FieldName="DueDate" />
</Columns>
</DxTreeList>
@code {
List<EmployeeTask> TreeListData { get; set; }
protected override void OnInitialized() {
TreeListData = EmployeeTaskService.GenerateData();
}
void TreeList_CustomizeEditModel(TreeListCustomizeEditModelEventArgs e) {
if(e.IsNew) {
var newTask = (EmployeeTask)e.EditModel;
newTask.Id = TreeListData.Max(x => x.Id) + 1;
if(e.ParentDataItem != null)
newTask.ParentId = ((EmployeeTask)e.ParentDataItem).Id;
}
}
async Task TreeList_EditModelSaving(TreeListEditModelSavingEventArgs e) {
if(e.IsNew)
TreeListData.Add((EmployeeTask)e.EditModel);
else
e.CopyChangesToDataItem();
}
async Task TreeList_DataItemDeleting(TreeListDataItemDeletingEventArgs e) {
TreeListData.Remove((EmployeeTask)e.DataItem);
}
}