When using PnP Core SDK inside .net core console application, how the date & time format and time zone will be handled for adding and updating Dates Values

[mvcsharepointdev]

I have a sharepoint site with a timezone of UTC+3.

I have 2 hosting servers:-

1. One with UTC+3.
   

2. And the second with UTC+1.
   

I created 2 SharePoint lists:-

1. SourceD
2. DestinationD

I have this console application where i am trying to understand how the Dates & times timezone and format will be retrieved and set. The console application will do these main actions:-

• Retrieve the list item from SourceD list

• Show the "D" value using Write-Line

• Add a new item inside DestinationD list and show the list item's "D" value.

namespace ConsoleApp4
{
    internal class Program
    {
        static async Task Main(string[] args)
        {
            var tenantId = "**";
            var clientId = "**";
            var certificatePath = @"c:\CERT\***.pfx";
            var certificatePassword = "****";

            // Initialize a new service collection
            var serviceCollection = new ServiceCollection();

            // Load the certificate
            var certificate = new X509Certificate2(certificatePath, certificatePassword, X509KeyStorageFlags.Exportable);

            // Configure logging
            serviceCollection.AddLogging(builder =>
            {
                builder.AddConsole();
            });

            // Add and configure PnP Core SDK
            serviceCollection.AddPnPCore(options =>
            {
                options.PnPContext.GraphFirst = true; // Set true if you prefer to use Graph over CSOM when possible
                                                      // options.HttpRequests.UserAgent = "ISV|Contoso|ProductX";
                options.Sites.Add("SiteToWorkWith", new PnPCoreSiteOptions
                {
                    SiteUrl = "https://**.sharepoint.com/sites/PPM",
                    AuthenticationProvider = new X509CertificateAuthenticationProvider(clientId, tenantId, certificate)
                });
            });

            // Build the service provider
            var serviceProvider = serviceCollection.BuildServiceProvider();

            // Use the service provider to get the IPnPContextFactory instance
            var pnpContextFactory = serviceProvider.GetRequiredService<IPnPContextFactory>();

            // Now you can use the IPnPContextFactory to get a PnPContext and perform operations
            var context = await pnpContextFactory.CreateAsync("SiteToWorkWith");

            var destinationList = context.Web.Lists.GetByTitle("DestinationD", p => p.Title,
                                                                                               p => p.Fields.QueryProperties(
                                                                                               p => p.InternalName,
                                                                                               p => p.FieldTypeKind,
                                                                                               p => p.TypeAsString,
                                                                                               p => p.Title
                                                                                               ));
            var sourceList = context.Web.Lists.GetByTitle("SourceD", p => p.Title,
                                                                 p => p.Fields.QueryProperties(p => p.InternalName,
                                                                                               p => p.FieldTypeKind,
                                                                                               p => p.TypeAsString,
                                                                                               p => p.Title));

            // Build a query that only returns these fields for the Work Orders
            string viewXml = @"<View Scope='RecursiveAll'>
                    <ViewFields>
                      <FieldRef Name='Title' />
                      <FieldRef Name='Created' />
                      <FieldRef Name='FileLeafRef' />
                        <FieldRef Name='D' />
                        <FieldRef Name='Modified' />
                      
                    </ViewFields>
                                        <Query>
                    </Query>
                   <RowLimit Paged='TRUE'>5000</RowLimit>
                   </View>";

            // Load all the needed data using paged requests
            bool paging = true;
            string nextPage = null;
            while (paging)
            {
                var output = await sourceList.LoadListDataAsStreamAsync(new RenderListDataOptions()
                {
                    ViewXml = viewXml,
                    RenderOptions = RenderListDataOptionsFlags.ListData,
                    Paging = nextPage ?? null,
                }).ConfigureAwait(false);

                if (output.ContainsKey("NextHref"))
                {
                    nextPage = output["NextHref"].ToString().Substring(1);
                }
                else
                {
                    paging = false;
                }
            }

       var sourceitems = sourceList.Items.AsRequested()
       .Select(wo =>
       {

           var createdStr = wo["Created"] != null ? wo["Created"].ToString() : null;
           var modifiedStr = wo["Modified"] != null ? wo["Modified"].ToString() : null;
           var dStr = wo["D"] != null ? wo["D"].ToString() : null;

           return new
           {
               c = createdStr,
               m = modifiedStr,
               dStr = dStr
           };
       }).ToList();


            foreach (var item in sourceitems)
            {
                Console.WriteLine(item.dStr);
                Console.WriteLine(DateTime.Parse(item.dStr.ToString()).ToString("yyyy-MM-ddTHH:mm:ssZ"));
                Dictionary<string, object> logitem = new Dictionary<string, object>() {
                    { "Title", DateTime.Now },{"D",item.dStr}
                    };

                var newlogitem = await destinationList.Items.AddAsync(logitem);
                Console.WriteLine(logitem["D"]);
            }

            Console.ReadLine();

            context.Dispose();

        }


    }

I added a column of type Date/Time named "D" inside both lists. Then i added a list item inside the SourceD with this value:-

Where the console application behave as follow:-

1. On the hosting server with UTC+3, it showed the Date & Time retrieved as follow (08/10/2024 14:30):-
   

and it added a new list item inside the Destination list as follow:-

2. On the hosting server with UTC+1, it showed the Date & Time retrieved as follow (08/10/2024 13:40) which is one hour behind the sharepoint site and which matches the local server time zone:-
   

and it raised this error when it tried to add the new item, that it can not find a field named "D":-

So i have those questions:-

1. So seems the PnP Core SDK will not show the date/times using the SharePoint site timezone and format , but rather the hosting server timezone.. But if this was the case then how adding the new items worked well, i thought it will send the date/time in UTC+3 and sharepoint will assume this is in UTC format.. but PnP core SDK was smart enough to retrieve the Date/Time in local setting but send it to sharepoint after converting ti to UTC.. was this the case?

2. Also why i got an error when i tried to save the list item on the second hosting server , that it can not find a field with internal name = "D"?

Any advice please?
Thanks

[jansenbe]

We'll handle time zone settings via the code in https://github.com/pnp/pnpcore/blob/dev/src/sdk/PnP.Core/Model/SharePoint/Core/Internal/TimeZone.cs#L41-L185. When you create a PnPContext for a specific site we'll always retrieve the regional settings for the web and use that to handle date time transformations. When a date is saved back to SharePoint it's translated to the date required for the time zone set for the site (https://github.com/pnp/pnpcore/blob/dev/src/sdk/PnP.Core/Model/SharePoint/Core/Internal/ListItem.cs#L686).

[mvcsharepointdev]

@jansenbe but per my knowledge, sharepoint api expects the date to be in UTC format/timezone, am i correct? not in the site timezone?

[jansenbe]

I guess that's true for CSOM as we're not manipulating dates when saving via CSOM. When using the ValidateUpdateListItem REST API we are