DxPivotTable.LayoutAutoLoading Event
Fires when the DxPivotTable component is initialized and starts to load its layout.
Namespace: DevExpress.Blazor.PivotTable
Assembly: DevExpress.Blazor.PivotTable.v25.1.dll
NuGet Package: DevExpress.Blazor.PivotTable
Declaration
[Parameter]
public Func<PivotTablePersistentLayoutEventArgs, Task> LayoutAutoLoading { get; set; }Parameters
| Type | Description |
|---|---|
| PivotTablePersistentLayoutEventArgs | A PivotTablePersistentLayoutEventArgs object that defines data for this event. |
Remarks
Handle the LayoutAutoLoading event to restore a Pivot Table layout when the component is initialized. The component starts loading the layout after the initial component state specified in the markup is applied. As an alternative, call the LoadLayout(PivotTablePersistentLayout) method to restore the layout on demand (for example, on a button click).
Use the PivotTable event argument and its members to obtain additional information about the Pivot Table. The Layout argument specifies the layout applied to the Pivot Table.
You can obtain an object that stores Pivot Table layout in one of the following ways:
- Use the LayoutAutoSaving event’s e.Layout argument.
- Use the object returned by the SaveLayout() method.
- Create an object that stores the Pivot Table layout manually and convert it to the PivotTablePersistentLayout type using the Deserialize method.
You can use the following approach to implement different default layouts for mobile and desktop devices:
- Save layouts to a database instead of browser storage in the LayoutAutoSaving event handler.
- In the
LayoutAutoLoadingevent handler, use the DxLayoutBreakpoint component to load the layout based on the screen size.
Example
The following code snippet demonstrates how to implement layout persistence for a Pivot Table. When layout changes, the LayoutAutoSaving event handler saves the updated layout to the browser’s local storage. Once the page is reloaded or restored, the LayoutAutoLoading event handler loads the most recently saved layout from the local storage and applies it to the Pivot Table.
@using System.Text.Json
@inject NwindDataService NwindDataService
@inject IJSRuntime JSRuntime
<DxPivotTable @ref="@PivotTable"
Data="@PivotData"
VirtualScrollingEnabled="true"
LayoutAutoLoading="PivotTable_LayoutAutoLoading"
LayoutAutoSaving="PivotTable_LayoutAutoSaving">
<Fields>
<DxPivotTableField Field="SalesPerson" Area="PivotTableArea.Row" Caption="Sales Person" Width="270"/>
<DxPivotTableField Field="ProductName" Area="PivotTableArea.Row" Caption="Product Name"/>
<DxPivotTableField Field="ProductAmount" Area="PivotTableArea.Data" Caption="Product Amount" CellFormat="{0:c0}"/>
<DxPivotTableField Field="Discount" Area="PivotTableArea.Data" CellFormat="{0:p0}"/>
<DxPivotTableField Field="Country" AreaIndex="1"/>
<DxPivotTableField Field="Region" AreaIndex="0"/>
<DxPivotTableField Field="City" AreaIndex="-1"/>
<DxPivotTableField Field="ExtendedPrice" AreaIndex="-1"/>
<DxPivotTableField Field="OrderDate" GroupInterval="PivotTableGroupInterval.DateYear" Area="PivotTableArea.Column" Caption="Order Year" />
<DxPivotTableField Field="OrderDate" GroupInterval="PivotTableGroupInterval.DateQuarter" Area="PivotTableArea.Column" Caption="Order Quater">
<ValueTemplate>
<span>@($"Q{context.Text}")</span>
</ValueTemplate>
</DxPivotTableField>
</Fields>
</DxPivotTable>
@code {
const string LocalStorageKey = "PivotTable-LayoutPersistence-Data";
object PivotData { get; set; }
IPivotTable PivotTable { get; set; }
bool PreRendered { get; set; }
protected override void OnAfterRender(bool firstRender) {
if(firstRender) {
PreRendered = true;
StateHasChanged();
}
}
protected override async Task OnInitializedAsync() {
var invoices = await NwindDataService.GetInvoicesAsync();
var customers = await NwindDataService.GetCustomersAsync();
var minDate = invoices.Min(i => i.OrderDate).GetValueOrDefault();
var maxDate = invoices.Max(i => i.OrderDate).GetValueOrDefault();
PivotData = invoices.Where(i => {
var invoiceDate = i.OrderDate.GetValueOrDefault();
return invoiceDate.Year > minDate.Year && invoiceDate.Year <= maxDate.Year;
}).Join(customers, i => i.CustomerId, c => c.CustomerId, (i, c) => {
return new {
CompanyName = c.CompanyName,
UnitPrice = i.UnitPrice,
OrderDate = i.OrderDate,
ProductName = i.ProductName,
ProductAmount = i.Quantity * i.UnitPrice,
Country = c.Country,
Region = c.Region,
ExtendedPrice = i.ExtendedPrice,
City = c.City,
Discount = i.Discount,
SalesPerson = i.Salesperson,
};
});
}
async Task PivotTable_LayoutAutoLoading(PivotTablePersistentLayoutEventArgs e) {
e.Layout = await LoadLayoutFromLocalStorageAsync();
}
async Task PivotTable_LayoutAutoSaving(PivotTablePersistentLayoutEventArgs e) {
await SaveLayoutToLocalStorageAsync(e.Layout);
}
// Refer to https://docs.microsoft.com/en-us/aspnet/core/blazor/state-management
// to learn more about Blazor state management
// In Blazor Server apps, prefer ASP.NET Core Protected Browser Storage
async Task<PivotTablePersistentLayout> LoadLayoutFromLocalStorageAsync() {
try {
var json = await JSRuntime.InvokeAsync<string>("localStorage.getItem", LocalStorageKey);
return JsonSerializer.Deserialize<PivotTablePersistentLayout>(json);
} catch {
// Mute exceptions for the server prerender stage
return null;
}
}
async Task SaveLayoutToLocalStorageAsync(PivotTablePersistentLayout layout) {
try {
var json = JsonSerializer.Serialize(layout);
await JSRuntime.InvokeVoidAsync("localStorage.setItem", LocalStorageKey, json);
} catch {
// Mute exceptions for the server prerender stage
}
}
async Task RemoveLayoutFromLocalStorageAsync() {
try {
await JSRuntime.InvokeVoidAsync("localStorage.removeItem", LocalStorageKey);
} catch {
// Mute exceptions for the server prerender stage
}
}
async Task ReloadPageButton_ClickAsync() {
await JSRuntime.InvokeVoidAsync("location.reload");
}
async Task ResetLayoutButton_ClickAsync() {
await RemoveLayoutFromLocalStorageAsync();
await JSRuntime.InvokeVoidAsync("location.reload");
}
void FieldListButton_Click() {
PivotTable.ShowFieldList();
}
}
