DxTreeList.ShowRowDeleteConfirmation(Int32) Method

Displays the delete confirmation dialog for the specified row. If a user confirms the operation, the method raises the DataItemDeleting event.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v24.2.dll

NuGet Package: DevExpress.Blazor

Declaration

public void ShowRowDeleteConfirmation(
    int visibleIndex
)

Parameters

Name	Type	Description
visibleIndex	Int32	The row’s visible index.

Remarks

This method allows you to implement your custom Delete button inside or outside the TreeList.

Handle a button’s click event and call the ShowRowDeleteConfirmation method to display the delete confirmation dialog for the specified row. The DataItemDeleting event fires when a user confirms the delete operation. Handle this event to check user access permissions and delete the data item from the underlying data source.

Note

When the TreeList is bound to the GridDevExtremeDataSource or loads data on demand, call the WaitForRemoteSourceRowLoadAsync(Int32) method before you execute the ShowRowDeleteConfirmation method to ensure that the specified data row is loaded.

The TreeList also includes the following edit-related methods:

StartEditNewRowAsync

Starts editing a new row.

StartEditRowAsync

Start editing the specified row.

CancelEditAsync

Cancels row editing and discards changes.

SaveChangesAsync

Saves changes.

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

Razor

@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);
    }
}

EmployeeTask.cs

public class EmployeeTask{
    public int Id { get; set; }
    public int ParentId { get; set; }
    public string Name { get; set; }
    public string EmployeeName { get; set; }
    public DateTime StartDate { get; set; }
    public DateTime DueDate { get; set; }

    public EmployeeTask(
        int id,
        int parentId,
        string name,
        string employeeName,
        DateTime startDate,
        DateTime dueDate
    )
    {
        Id = id;
        ParentId = parentId;
        Name = name;
        EmployeeName = employeeName;
        StartDate = startDate;
        DueDate = dueDate;
    }
}

EmployeeTaskService.cs

public class EmployeeTaskService {
    public List<EmployeeTask> GenerateData() {
        return new List<EmployeeTask>() {
            new EmployeeTask(1, 0, "Simplify & Clarify Product Messaging", "John Heart", new DateTime(2018, 4, 3), new DateTime(2018, 4, 14)),
            new EmployeeTask(2, 1, "Prepare Financial Reports", "Samantha Bright", new DateTime(2018, 4, 3), new DateTime(2018, 4, 7)),
            new EmployeeTask(3, 1, "Prepare Marketing Plan", "Arthur Miller", new DateTime(2018, 4, 7), new DateTime(2018, 4, 14)),
            new EmployeeTask(4, 0, "Create Action Plan To Improve Customer Engagement", "Robert Reagan", new DateTime(2017, 8, 8), new DateTime(2018, 4, 8)),
            new EmployeeTask(5, 4, "Update Personnel Files", "Greta Sims", new DateTime(2017, 8, 8), new DateTime(2017, 10, 18)),
            new EmployeeTask(6, 4, "Review Health Insurance Options ", "Brett Wade", new DateTime(2017, 9, 27), new DateTime(2017, 11, 10)),
            new EmployeeTask(7, 4, "Choose Between PPO And HMO Health Plan", "Sandra Johnson", new DateTime(2017, 12, 13), new DateTime(2018, 3, 23)),
            new EmployeeTask(8, 4, "Update Google Adwords Strategy", "Ed Holmes", new DateTime(2017, 8, 23), new DateTime(2017, 12, 23)),
            new EmployeeTask(9, 4, "Create New Brochure Design", "Barb Banks", new DateTime(2018, 1, 3), new DateTime(2018, 3, 14)),
            new EmployeeTask(10, 4, "Obtain Price Quote For New Brochure", "Kevin Carter", new DateTime(2018, 2, 1), new DateTime(2018, 3, 15)),
            new EmployeeTask(11, 4, "Brochure Design Review", "Cindy Stanwick", new DateTime(2017, 8, 22), new DateTime(2017, 10, 28)),
            new EmployeeTask(12, 4, "Review Website Re-Design Strategy", "Sammy Hill", new DateTime(2017, 9, 16), new DateTime(2018, 3, 6)),
            new EmployeeTask(13, 4, "Rollout New Website", "Davey Jones", new DateTime(2017, 11, 7), new DateTime(2018, 2, 6)),
            new EmployeeTask(14, 4, "Update Sales/Marketing Strategy", "Victor Norris", new DateTime(2017, 12, 13), new DateTime(2018, 4, 2)),
            new EmployeeTask(15, 4, "Update Sales/Revenue Report", "Mary Stern", new DateTime(2017, 12, 25), new DateTime(2018, 4, 2)),
            new EmployeeTask(16, 4, "Direct Vs Online Sales Comparison Report", "Robin Cosworth", new DateTime(2018, 1, 2), new DateTime(2018, 3, 20)),
            new EmployeeTask(17, 4, "Review Sales Report and Approve Modifications", "Kelly Rodriguez", new DateTime(2017, 9, 4), new DateTime(2017, 10, 30)),
            new EmployeeTask(18, 4, "Update R&D Strategy", "James Anderson", new DateTime(2017, 11, 13), new DateTime(2017, 12, 4)),
            new EmployeeTask(19, 4, "Discuss Updated R&D Strategy", "Antony Remmen", new DateTime(2017, 10, 29), new DateTime(2017, 12, 31)),
            new EmployeeTask(20, 4, "Update QA Strategy", "Olivia Peyton", new DateTime(2017, 10, 31), new DateTime(2017, 11, 2)),
            new EmployeeTask(21, 4, "Schedule Training Events", "Taylor Riley", new DateTime(2017, 11, 19), new DateTime(2018, 4, 7)),
            new EmployeeTask(22, 4, "Approve The Hiring Of John Jeffers", "Amelia Harper", new DateTime(2018, 1, 7), new DateTime(2018, 4, 8)),
            new EmployeeTask(23, 0, "Increase Average Subscription Price ", "Wally Hobbs", new DateTime(2017, 8, 9), new DateTime(2017, 9, 13)),
            new EmployeeTask(24, 23, "Update Non-Compete Agreements", "Brad Jameson", new DateTime(2017, 8, 9), new DateTime(2017, 9, 3)),
            new EmployeeTask(25, 23, "Update Employee Records With New NDA", "Karen Goodson", new DateTime(2017, 8, 23), new DateTime(2018, 9, 10))
        };
    }
}

Program.cs

// ...
builder.Services.AddSingleton<EmployeeTaskService>();

Refer to the following topic for more information: Editing and Validation in Blazor TreeList.

Implements

ShowRowDeleteConfirmation(Int32)

ShowRowDeleteConfirmation(Int32)