Save and Restore Layout
- 9 minutes to read
The Blazor Pivot Table allows you to save and restore its layout. Use this functionality to implement the following scenarios:
- Persist layout between application runs to retain users’ changes.
- Allow users to save their preferred layouts and return to them when necessary.
- Configure pre-defined layouts and allow users to switch between them.
A saved layout object (PivotTablePersistentLayout) includes the following data:
Saved information | PivotTablePersistentLayout’s property |
---|---|
Expand/collapse state for rows and columns | Layout.ExpandCollapseState |
Filter values. All Pivot Table field filter criteria[1] combined by logical AND . |
Layout.FilterCriteria |
Settings for individual fields. See the table below. | Layout.Fields.Item(i) |
The PivotTablePersistentLayout.Fields collection stores information about field settings. Each collection item (PivotTablePersistentLayoutField object) includes the following data:
Saved information | Pivot Table field parameter | PivotTablePersistentLayoutField’s property |
---|---|---|
Data source field name | DxPivotTableField.Field | LayoutField.Field |
Area | DxPivotTableField.Area | LayoutField.Area |
Field index within its area | DxPivotTableField.AreaIndex | LayoutField.AreaIndex |
Sort direction | DxPivotTableField.SortOrder | LayoutField.SortOrder |
Persist Layout Between Application Runs
To save and restore the Pivot Table layout automatically, handle the following events:
- LayoutAutoSaving
- Fires each time the Pivot Table’s layout changes and allows you to save the layout.
- LayoutAutoLoading
- Fires once the Pivot Table component is initialized and allows you to restore the saved layout.
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();
}
}
Save and Restore the Layout on Demand
To save and restore the Pivot Table layout when necessary (for example, on a button click), call the following methods:
- SaveLayout()
- Returns Pivot Table layout information so you can save it to a variable or a custom storage.
- LoadLayout(PivotTablePersistentLayout)
- Restores Pivot Table layout.
The following code snippet displays two buttons: Save Layout and Load Layout. When a user clicks the first button, the current Pivot Table layout is saved to the Layout
variable. Once a user clicks the second button, the component loads the most recently saved layout and applies it to the Pivot Table.
@rendermode InteractiveServer
@using Services
<DxButton Text="Save Layout" Click="OnSaveClick" />
<DxButton Text="Load Layout" Click="OnLoadClick" />
<DxPivotTable Data="SalesData" @ref=MyPivotTable >
<Fields>
<DxPivotTableField Field="@nameof(Sales.SaleInfo.Region)"
Area="@PivotTableArea.Row"
AreaIndex="0" />
<DxPivotTableField Field="@nameof(Sales.SaleInfo.Country)"
Area="@PivotTableArea.Row"
SortOrder="@PivotTableSortOrder.Descending"
AreaIndex="1" />
<DxPivotTableField Field="@nameof(Sales.SaleInfo.Date)"
GroupInterval="@PivotTableGroupInterval.DateYear"
Area="@PivotTableArea.Column"
AreaIndex="0"
Caption="Year" />
<DxPivotTableField Field="@nameof(Sales.SaleInfo.Date)"
GroupInterval="@PivotTableGroupInterval.DateQuarter"
Area="@PivotTableArea.Column"
AreaIndex="1"
Caption="Quarter" />
<DxPivotTableField Field="@nameof(Sales.SaleInfo.Amount)"
SortOrder="@PivotTableSortOrder.Ascending"
Area="@PivotTableArea.Data"
SummaryType="@PivotTableSummaryType.Sum" />
<DxPivotTableField Field="@nameof(Sales.SaleInfo.City)"
Area="@PivotTableArea.Filter"/>
</Fields>
</DxPivotTable>
@code {
IPivotTable MyPivotTable { get; set; }
PivotTablePersistentLayout Layout { get; set; }
IEnumerable<Sales.SaleInfo> SalesData;
protected override async Task OnInitializedAsync() {
SalesData = await Sales.GetSalesAsync();
}
void OnSaveClick() {
Layout = MyPivotTable.SaveLayout();
}
void OnLoadClick() {
MyPivotTable.LoadLayout(Layout);
}
}
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DevExpress components can incorrectly serialize custom enumeration values in criteria operators. Refer to the following troubleshooting topic for more information: The XXX enumeration type is not registered for the parse operation…