ITimeZoneProvider Interface

Provides information about the local time zone in the UtcToLocalTime and LocalToUtcTime expression functions.

Namespace: DevExpress.XtraReports.Services

Assembly: DevExpress.XtraReports.v25.2.dll

Declaration

C#

public interface ITimeZoneProvider

VB.NET

Public Interface ITimeZoneProvider

Remarks

You can use UtcToLocalTime and LocalToUtcTime functions to convert date-time values to local or UTC time zones. The local time zone is determined by the server’s settings. To provide a different time zone (for example, the client’s time zone), implement the ITimeZoneProvider interface. The GetCurrentTimeZone method should return a TimeZoneInfo object that is the local time zone.

The following example implements the ITimeZoneProvider interface in an ASP.NET Core application. In this example, the time zone is retrieved from a cookie named LocalTimeZone.

1. Create a class that implements the ITimeZoneProvider interface:

using System;
using DevExpress.XtraReports.Services;
using Microsoft.AspNetCore.Http;

namespace AspNetCoreApp.Services {
    public class CustomTimeZoneProvider : ITimeZoneProvider {
        private readonly string timeZoneId;

        public CustomTimeZoneProvider(IHttpContextAccessor httpContextAccessor) {
            timeZoneId = httpContextAccessor.HttpContext?.Request.Cookies["LocalTimeZone"];
        }

        public TimeZoneInfo GetCurrentTimeZone() {
            var tzId = timeZoneId ?? "UTC";
            try {
                return TimeZoneInfo.FindSystemTimeZoneById(tzId);
            } catch {
                return TimeZoneInfo.Utc;
            }
        }
    }
}

2. In the Program.cs file, register the CustomTimeZoneProvider service:

   using DevExpress.XtraReports.Services;
   using Microsoft.AspNetCore.Builder;
   using Microsoft.Extensions.DependencyInjection;
   using AspNetCoreApp.Services;
   
   var builder = WebApplication.CreateBuilder(args);
   // ...
   builder.Services.AddScoped<ITimeZoneProvider, CustomTimeZoneProvider>();
   builder.Services.AddHttpContextAccessor();
   // ...
   var app = builder.Build();
   // ...
   app.Run();
   

3. In the view, set the LocalTimeZone cookie to the client’s time zone:

   @model DevExpress.XtraReports.Web.WebDocumentViewer.WebDocumentViewerModel
   @{
       var viewerRender = Html.DevExpress().WebDocumentViewer("DocumentViewer")
           .Height("100%")
           .Bind(Model);
       @viewerRender.RenderHtml()
   }
   
   @section Scripts {
       <link href="~/css/dx-reporting-skeleton-screen.css" rel="stylesheet" />
       <link rel="stylesheet" href="~/css/viewer.part.bundle.css" />
       <link rel="stylesheet" href="~/css/dx.material.blue.light.bundle.css" />
       <script src="~/js/reporting.thirdparty.bundle.js"></script>
       <script src="~/js/viewer.part.bundle.js"></script>
       <script>
           document.addEventListener("DOMContentLoaded", () => {
               const tz = Intl.DateTimeFormat().resolvedOptions().timeZone;
               document.cookie = "LocalTimeZone=" + tz + "; path=/";
           });
       </script>
       @viewerRender.RenderScripts()
   }
   

In desktop applications, register the ITimeZoneProvider implementation at the XtraReport instance level.