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V24.2

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DxTreeListCommandColumn.HeaderTemplate Property

Specifies a template used to display the command column header.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v24.2.dll

NuGet Package: DevExpress.Blazor

#Declaration

#Property Value

Type Description
RenderFragment<TreeListCommandColumnHeaderTemplateContext>

A template for the command column header.

#Remarks

The command column displays predefined New, Edit, and Delete buttons for data rows in display mode. In EditRow and EditCell edit modes, this column displays Save and Cancel buttons for the edited row. In the filter row, the column displays the Clear button.

Blazor TreeList Command Column

Read Tutorial: Editing and Validation in Blazor TreeList Read Tutorial: Templates in Blazor TreeList

Define the HeaderTemplate to display custom content in the command column header. Use the template’s context parameter to access the CommandColumn object. The TreeList object allows you to access the component and call edit-related methods. For instance, call the StartEditNewRowAsync method to start editing a new data row.

Specify the CellDisplayTemplate to display custom command elements for cells in display mode. The CellEditTemplate allows you to display custom command elements for cells in edit mode. To display custom content in the filter row, define the FilterRowCellTemplate.

Note

Add, Edit, and Delete operations can be temporarily unavailable if you bind the TreeList to the GridDevExtremeDataSource or load data on demand. Use the following template parameters to specify the enabled or disabled state for custom command elements:

The following code snippet displays icons instead of default command buttons:

@inject EmployeeTaskService EmployeeTaskService

<DxTreeList @ref="MyTreeList"
            Data="TreeListData"
            KeyFieldName="Id"
            ParentKeyFieldName="ParentId"
            EditMode="TreeListEditMode.EditForm"
            EditModelSaving="TreeList_EditModelSaving"
            DataItemDeleting="TreeList_DataItemDeleting"
            CustomizeEditModel="TreeList_CustomizeEditModel">
    <Columns>
        <DxTreeListCommandColumn Width="90px">
            <HeaderTemplate>
                <a class="oi oi-plus" @onclick="@(() => MyTreeList.StartEditNewRowAsync())" style="text-decoration: none;" href="javascript:void(0);"></a>
            </HeaderTemplate>
            <CellDisplayTemplate>
                <a class="oi oi-pencil" @onclick="@(() => MyTreeList.StartEditRowAsync(context.VisibleIndex))" style="text-decoration: none;" href="javascript:void(0);"></a>
                <a class="oi oi-plus" @onclick="@(() => MyTreeList.StartEditNewRowAsync(context.VisibleIndex))" style="text-decoration: none;" href="javascript:void(0);"></a>
                <a class="oi oi-x" @onclick="@(() => MyTreeList.ShowRowDeleteConfirmation(context.VisibleIndex))" style="text-decoration: none;" href="javascript:void(0);"></a>
            </CellDisplayTemplate>
        </DxTreeListCommandColumn>
        <DxTreeListDataColumn FieldName="Name" Caption="Task" />
        <DxTreeListDataColumn FieldName="EmployeeName" />
        <DxTreeListDataColumn FieldName="StartDate" />
        <DxTreeListDataColumn FieldName="DueDate" />
    </Columns>
    <EditFormTemplate Context="EditFormContext">
        <DxFormLayout CssClass="w-100">
            <DxFormLayoutItem Caption="Task:" ColSpanMd="6">
                @EditFormContext.GetEditor("Name")
            </DxFormLayoutItem>
            <DxFormLayoutItem Caption="Employee Name:" ColSpanMd="6">
                @EditFormContext.GetEditor("EmployeeName")
            </DxFormLayoutItem>
            <DxFormLayoutItem Caption="Start Date:" ColSpanMd="6">
                @EditFormContext.GetEditor("StartDate")
            </DxFormLayoutItem>
            <DxFormLayoutItem Caption="Due Date:" ColSpanMd="6">
                @EditFormContext.GetEditor("DueDate")
            </DxFormLayoutItem>
        </DxFormLayout>
    </EditFormTemplate>
</DxTreeList>

@code {
    ITreeList MyTreeList { get; set; }
    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);
    }
}

Blazor TreeList Editing Custom Command Buttons

#Implements

See Also