Cell Editing in Blazor TreeList

• Dec 03, 2024
• 9 minutes to read

In EditCell mode, users can click a data cell to display its in-place editor. When focus moves to another row, the control validates pending user input and saves changes.

Run Demo: Edit Cell Run Demo: Edit Batch View Example: Implement Batch Data Editing Using Entity Framework Core

The following shortcuts are available in EditCell mode:

Enter

Displays an in-place editor in the focused data cell or hides the cell editor and validates the cell value.

Esc

When a cell editor is visible, a user can press the Esc key to hide the editor and discard changes made in this cell. If the user presses Esc when the editor is hidden, the TreeList discards all changes made in the row and cancels row editing.

Tab or Shift+Tab

Hides the editor in the current cell, focuses the next or previous data cell, and shows an editor in the newly focused cell.

Enable Editing

Follow the steps below to enable cell editing:

1. Set the EditMode property to EditCell.

2. If your data object has a primary key, assign it to the KeyFieldName property. Otherwise, the TreeList uses standard .NET value equality comparison to identify data items.

3. Handle the CustomizeEditModel event to initialize an edit model for new data rows.
4. Handle EditModelSaving and DataItemDeleting events to save changes and reload TreeList data.
5. (Optional) Declare a DxTreeListCommandColumn object in the Columns template to display the command column.
6. (Optional). Use the EditNewRootRowPosition property to display the new item row or change the position of cell editors displayed for new root nodes.

Razor

@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" />
        <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);
    }
}

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>();

New Item Row

The new item row is an empty row that allows users to add new root nodes. Set the EditNewRootRowPosition property to FixedOnTop to display the new item row fixed to the top of the current page. Set this property to LastRow to display this row on the last page after the last data row.

<DxTreeList Data="TreeListData"
            KeyFieldName="Id"
            ParentKeyFieldName="ParentId"
            EditMode="TreeListEditMode.EditCell"
            EditModelSaving="TreeList_EditModelSaving"
            DataItemDeleting="TreeList_DataItemDeleting"
            CustomizeEditModel="TreeList_CustomizeEditModel"
            EditNewRowPosition="TreeListEditNewRowPosition.FixedOnTop">
    <Columns>
        *@* ... *@
    </Columns>
</DxTreeList>

Users can press Tab or Shift + Tab keys to navigate between the new item row’s data cells. If focus goes beyond the last/first data cell, the TreeList focuses the cell on the opposite end and validates user input. Depending on validation results, the following variants are possible:

• If validation fails, the component displays error icons.
• If validation succeeds, the component saves changes and starts editing a new root node.

Limitations

The EditCell mode has the following specifics and limitations:

• The mode is compatible only with DevExpress Blazor editors.
• The TreeList component does not support this mode when you use a GridDevExtremeDataSource.
• After a user performs a data shaping operation that hides the edited row from the view (for instance, after a user collapses the parent of the edited row), the TreeList validates row values. If validation succeeds, the TreeList saves changes. If validation fails, the TreeList discards changes and displays a notification message: “Unsaved changes were discarded”.
• During edit operations, the TreeList applies user changes only to the edit model and keeps the data item unchanged. To display modified values in the CellDisplayTemplate or DataColumnCellDisplayTemplate, use the edit model’s field values instead of the template context’s DataItem, DisplayText, and Value properties. You can obtain the edit model as follows:

  <DxTreeListDataColumn FieldName="FirstName">
      <CellDisplayTemplate Context="displayContext">
          @{
              string value;
              if (displayContext.TreeList.IsEditingRow(displayContext.VisibleIndex)) {
                  var editModel = (Employee)displayContext.TreeList.GetEditContext().Model;
                  value = editModel.FirstName;
              }
              else
                  value = displayContext.DisplayText;
          }
          <span>@value</span>
      </CellDisplayTemplate>
  </DxTreeListDataColumn>
  

Related API

This section contains comprehensive editing-related API references.

Show API References

DxTreeList API Member	Type	Description
CustomValidators	Property	Allows you to declare custom validator components.
DataColumnCellEditTemplate	Property	Allows you to replace automatically generated editors with custom content in all edit cells displayed for data columns.
EditMode	Property	Specifies how users can edit TreeList data.
EditNewRootRowPosition	Property	Specifies the position of UI elements used to create new root nodes.
ValidationEnabled	Property	Specifies whether the TreeList validates user input.
CancelEditAsync()	Method	Cancels row editing and discards changes.
GetColumnEditSettings<T>(String)	Method	Returns editor settings of the column bound to the specified data source field.
GetEditContext()	Method	Returns the edit context.
IsEditing()	Method	Returns whether the TreeList is being edited.
IsEditingNewRow()	Method	Returns whether a new TreeList row is being edited.
IsEditingRow(Int32)	Method	Returns whether the specified TreeList row is being edited.
SaveChangesAsync()	Method	Triggers validation and raises the EditModelSaving event if validation succeeds. The method immediately raises this event if validation is disabled.
ShowRowDeleteConfirmation(Int32)	Method	Displays the delete confirmation dialog for the specified row. If a user confirms the operation, the method raises the DataItemDeleting event.
StartEditNewRowAsync(String)	Method	Starts editing a new root node.
StartEditNewRowAsync(Int32, String)	Method	Starts editing a new child node of the row with the specified visible index.
StartEditRowAsync(Int32, String)	Method	Starts editing the row with the specified visible index.
CustomizeDataRowEditor	Event	Allows you to customize a cell editor in a data row.
CustomizeEditModel	Event	Allows you to customize an automatically generated edit model or create a custom edit model.
DataItemDeleting	Event	Fires after a user confirms the delete operation in the delete confirmation dialog.
EditCanceling	Event	Fires before the TreeList cancels the edit operation and discards changes.
EditModelSaving	Event	Fires if validation succeeds after a user saves changes or you call the SaveChangesAsync() method.
EditStart	Event	Fires before the TreeList starts editing a row.

DxTreeListCommandColumn API Member	Type	Description
CancelButtonVisible	Property	Specifies whether the command column displays the Cancel button in EditRow or EditCell edit mode.
CellDisplayTemplate	Property	Specifies a template used to display command column cells in display mode.
CellEditTemplate	Property	Specifies a template used to display the command column’s edit cell.
DeleteButtonVisible	Property	Specifies whether the command column displays Delete buttons.
EditButtonVisible	Property	Specifies whether the command column displays Edit buttons.
HeaderTemplate	Property	Specifies a template used to display the command column header.
NewButtonVisible	Property	Specifies whether the command column displays New buttons.
SaveButtonVisible	Property	Specifies whether the command column displays the Save button in EditRow or EditCell edit mode.

DxTreeListDataColumn API Member	Type	Description
CellEditTemplate	Property	Allows you to replace an automatically generated editor with custom content in the column’s edit cell.
DataRowEditorVisible	Property	Specifies whether to render the editor associated with this column in the column edit cell, edit form, or pop-up edit form.
EditSettings	Property	Allows you to customize the editor associated with this column.
ReadOnly	Property	Specifies whether a user can change the column editor value when the TreeList is in edit mode.