ITreeListCommandColumn Interface
An interface that defines a TreeList command column‘s API members (properties and methods).
Namespace: DevExpress.Blazor
Assembly: DevExpress.Blazor.v24.2.dll
NuGet Package: DevExpress.Blazor
Declaration
public interface ITreeListCommandColumn :
ITreeListColumnRelated API Members
The following members return ITreeListCommandColumn objects:
Remarks
Use the ITreeListCommandColumn interface when you access a TreeList command column’s API members as follows:
- You use the
@refattribute to reference a TreeList command column. - You access a
CommandColumnobject from templates or event handlers. - You access elements of the TreeList column collection (for instance, the collection that the GetColumns() method returns).
In other cases, bind your data to column parameters.
Note
To change values of a TreeList command column’s parameters outside the component’s markup, enclose your code between BeginUpdate() and EndUpdate() method calls. Otherwise, an exception occurs.
The following code snippet displays a button that changes the command column’s visibility:
@inject EmployeeTaskService EmployeeTaskService
<style>
.my-button {
width: 300px;
}
</style>
<DxTreeList @ref="MyTreeList"
Data="TreeListData"
KeyFieldName="Id"
ParentKeyFieldName="ParentId"
EditModelSaving="TreeList_EditModelSaving"
DataItemDeleting="TreeList_DataItemDeleting"
CustomizeEditModel="TreeList_CustomizeEditModel">
<Columns>
<DxTreeListCommandColumn @ref="CommandColumn" Width="200px" />
<DxTreeListDataColumn FieldName="Name" Caption="Task" />
<DxTreeListDataColumn FieldName="EmployeeName" />
<DxTreeListDataColumn FieldName="StartDate" />
<DxTreeListDataColumn FieldName="DueDate" />
</Columns>
</DxTreeList>
<DxButton Text="Show/Hide the Command Column" Click="OnButtonClick" CssClass="my-button" />
@code {
ITreeList MyTreeList { get; set; }
ITreeListCommandColumn CommandColumn { get; set; }
List<EmployeeTask> TreeListData { get; set; }
void OnButtonClick() {
MyTreeList.BeginUpdate();
CommandColumn.Visible = !CommandColumn.Visible;
MyTreeList.EndUpdate();
}
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);
}
}
