LookupWebId Property

SPFieldLookup.LookupWebId Property

Gets or sets the ID of the Web site that contains the list that is the source of this field's value.

Namespace:  Microsoft.SharePoint
Assembly:  Microsoft.SharePoint (in Microsoft.SharePoint.dll)
Available in Sandboxed Solutions: Yes
Available in SharePoint Online

public Guid LookupWebId { get; set; }

Property Value

Type: System.Guid
The value of the ID property for the Web site.


The list that the field belongs to is an external list


Once set, the value of the property cannot be changed.

You must have SPBasePermissions.Open permissions to set this property.

The following example is a console application that queries a list's collection of fields for lookup fields. For each lookup field that is found, the application prints the name of the field, the title of the list that the lookup field points to, the field in the target list that is the source of the lookup field's value, and the name of the Web site where the source list is located.

using System;
using Microsoft.SharePoint;

namespace ConsoleApp
    class Program
        static void Main(string[] args)
            using (SPSite siteCollection = new SPSite("http://localhost"))
                using (SPWeb site = siteCollection.OpenWeb())
                    SPList list = site.Lists["Completed Orders"];

                    foreach (SPField item in list.Fields)
                        if (item is SPFieldLookup)
                            SPFieldLookup field = (SPFieldLookup)item;

                            if (!String.IsNullOrEmpty(field.LookupList) && !String.IsNullOrEmpty(field.LookupField))
                                // Is this the primary or secondary field for a list relationship?
                                string strRelationship = field.IsRelationship ? "Primary":"Secondary";

                                // Print the display name of the field.
                                Console.WriteLine("\nField: {0} ({1} Field)", field.Title, strRelationship);

                                // Is this a secondary field in a list relationship?
                                if (field.IsDependentLookup)
                                    SPField primaryField = list.Fields[new Guid(field.PrimaryFieldId)];
                                    Console.WriteLine("Primary Field: {0}", primaryField.Title);

                                // Get the site where the target list is located.
                                using (SPWeb targetSite = siteCollection.AllWebs[field.LookupWebId])
                                    // Get the name of the list where this field gets information.
                                    SPList targetList = targetSite.Lists[new Guid(field.LookupList)];
                                    Console.WriteLine("Related list: {0}", targetList.Title);

                                    // Get the name of the field where this field gets information.
                                    SPField targetField = targetList.Fields.GetFieldByInternalName(field.LookupField);
                                    Console.WriteLine("Related field: {0}", targetField.Title);
            Console.Write("\nPress ENTER to continue...");
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