public Action<GridDocumentExportCustomizeDocumentEventArgs> CustomizeDocument { get; set; }

@rendermode InteractiveServer
@using DevExpress.Drawing;
@inject WeatherForecastService ForecastService

<DxGrid @ref="Grid" Data="@forecasts">
    <Columns>
        <DxGridDataColumn Caption="Date" FieldName="Date" />
        <DxGridDataColumn Caption="Temperature (C)" FieldName="TemperatureC" />
        <DxGridDataColumn Caption="Temperature (F)" FieldName="TemperatureF" />
        <DxGridDataColumn Caption="Summary" FieldName="Summary" />
    </Columns>
    <ToolbarTemplate>
        <DxToolbar>
            <DxToolbarItem Text="Export to PDF" Click="ExportPdf_Click" BeginGroup="true" />
        </DxToolbar>
    </ToolbarTemplate>
</DxGrid>

@code {
    IGrid Grid;
    private WeatherForecast[]? forecasts;

    protected override async Task OnInitializedAsync() {
        forecasts = await ForecastService.GetForecastAsync(DateOnly.FromDateTime(DateTime.Now));
    }
    async Task ExportPdf_Click() {
        await Grid.ExportToPdfAsync("ExportResult", new GridPdfExportOptions() {
            CustomizeDocument = OnCustomizeDocument, // Customizes exported document appearance
            CustomizePageHeader = args => args.Text = "Weather Forecast", // Adds a page header
            CustomizePageFooter = args => args.Text = "Page {0} of {1}", // Adds a page footer
        });
    }
    void OnCustomizeDocument(GridDocumentExportCustomizeDocumentEventArgs args) {
        // Sets default font settings for all elements in the exported document
        args.DefaultElementStyle.Font = new DXFont("Times New Roman", 12, DXFontStyle.Regular);
        // Switches the page orientation to landscape
        args.Landscape = true;
        // Sets page margins to 0.5 inches
        args.Margins = new DXMargins(50, 50, 50, 50);
        // Sets the page size to a custom value (width: 6 inches, height: 8 inches)
        args.PaperKind = DevExpress.Drawing.Printing.DXPaperKind.Custom;
        args.PageSize = new System.Drawing.Size(600, 800);
    }
}

using System;

public class WeatherForecast {
    public DateTime Date { get; set; }
    public int TemperatureC { get; set; }
    public string Forecast { get; set; }
    public string CloudCover { get; set; }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

public class WeatherForecastService {
    private List<WeatherForecast> Forecast { get; set; }

    private static string[] CloudCover = new[] {
        "Sunny", "Partly cloudy", "Cloudy", "Stormy"
    };

    Tuple<int, string>[] ConditionsForForecast = new Tuple<int, string>[] {
        Tuple.Create( 22 , "Hot"),
        Tuple.Create( 13 , "Warm"),
        Tuple.Create( 0 , "Cold"),
        Tuple.Create( -10 , "Freezing")
    };

    public WeatherForecastService() {
        Forecast = CreateForecast();
    }

    private List<WeatherForecast> CreateForecast() {
        var rng = new Random();
        DateTime startDate = DateTime.Now;
        return Enumerable.Range(1, 30).Select(index => {
            var temperatureC = rng.Next(-10, 30);
            return new WeatherForecast {
                Date = startDate.AddDays(index),
                TemperatureC = temperatureC,
                CloudCover = CloudCover[rng.Next(0, 4)],
                Forecast = ConditionsForForecast.First(c => c.Item1 <= temperatureC).Item2
            };
        }).ToList();
    }

    public List<WeatherForecast> GetForecast() {
        return Forecast;
    }

    public Task<WeatherForecast[]> GetForecastAsync(CancellationToken ct = default) {
        return Task.FromResult(Forecast.ToArray());
    }
}

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