DataAsyncProperty.Cache.razor

@page "/DataAsyncUsingCache"
@inject WeatherForecastService WeatherForecastService

<h2>DataAsync: Cache Data</h2>

<p>
    This example uses the <a class="helplink" href="https://docs.devexpress.com/Blazor/DevExpress.Blazor.DxDataGrid-1.DataAsync" target="_blank">DataAsync</a> property to bind the Data Grid to a strongly typed collection that is loaded asynchronously. The <b>DataAsync</b> function can be called multiple times during the grid's life cycle because Blazor can re-render components. This example demonstrates how to cache this function if it is time- or resource-consuming.
</p>

<p>
    Note that the <b>Render GUID</b> does not change during page initialization. This means the page is rendered only once.
</p>

<p>
    <b>Render GUID</b>: @Guid.NewGuid()
</p>


<DxDataGrid DataAsync="@LoadDataAsync" KeyFieldName="Id">
    <Columns>
        <DxDataGridColumn Field="@nameof(WeatherForecast.Summary)" />
        <DxDataGridDateEditColumn Field="@nameof(WeatherForecast.Date)" />
        <DxDataGridSpinEditColumn Field="@nameof(WeatherForecast.TemperatureC)" />
        <DxDataGridSpinEditColumn Field="@nameof(WeatherForecast.TemperatureF)" />
    </Columns>
</DxDataGrid>
@code {
    IEnumerable<WeatherForecast> Cache;
    async Task<IEnumerable<WeatherForecast>> LoadDataAsync(CancellationToken token) {
        if (Cache == null)
            Cache = await WeatherForecastService.GetForecastAsync(DateTime.Now.Date);
        return Cache;
    }
}