Retrieve SharePoint Lookup Field Value Via C#

In this article, we will explain how to programmatically -

• Set a SharePoint Lookup Field (Multiple Values) via SSOM C#.
• Get a SharePoint Lookup Field (Multiple Values) via SSOM C#.
• Set a SharePoint Lookup Field (Single Value) via SSOM C#.
• Get a SharePoint Lookup Field (Single Value) via SSOM C#.

SET SPLOOKUP FIELD (MULTIPLE VALUES) USING SSOM C#

using(SPSite site = SPContext.Current.Site) {
    using(SPWeb web = site.OpenWeb()) {
        // Allow Unsafe Updates to prevent the cross site scripting
        web.AllowUnsafeUpdates = true;
        // Get The SPList
        SPList list = web.Lists["List Name"];
        // Add a new list item
        SPListItem item = list.Items.Add();
        // Set the default Title field
        item["Title"] = "string value";
        //Set Lookup Field - Multiple Values
        SPFieldLookupValueCollection itemValues = new SPFieldLookupValueCollection();
        foreach(ListItem litem in your collection) {
            itemValues.Add(new SPFieldLookupValue("A 32-bit integer that specifies the ID of the lookup field", "A string that contains the value of the lookup field"));
        }
        item["The Lookup Field Name"] = itemValues;
        // Submit your Item
        item.Update();
        web.AllowUnsafeUpdates = false;
    }
}

GET SPLOOKUP FIELD (MULTIPLE VALUES) USING SSOM C#

using(SPSite site = SPContext.Current.Site) {
    using(SPWeb web = site.OpenWeb()) {
        // Get The SPList
        SPList list = web.Lists["LookupField"];
        // Get a list item By ItemID
        SPListItem item = list.GetItemById("A 32-bit integer that specifies the ID of List Item");
        //Get Lookup Field - Multiple Values
        SPFieldLookupValueCollection MultipleValues = item["The Lookup Field Name"] as SPFieldLookupValueCollection;
        foreach(SPFieldLookupValue itemValue in MultipleValues) {
            ListItem litem = new ListItem();
            litem.Text = itemValue.LookupValue;
            litem.Value = itemValue.LookupId.ToString();
            dropdownlist.Items.Add(litem);
        }
    }
}

SET SPLOOKUP FIELD (SINGLE-VALUE) Via SSOM C#

using(SPSite site = SPContext.Current.Site) {
    using(SPWeb web = site.OpenWeb()) {
        // Allow Unsafe Updates to prevent the cross site scripting
        web.AllowUnsafeUpdates = true;
        // Get The SPList
        SPList list = web.Lists["List Name"];
        // Add a new list item
        SPListItem item = list.Items.Add();
        // Set the default Title field
        item["Title"] = "String Value";
        //Set the Lookup Field - Single Value
        item["The Lookup Field Name"] = new SPFieldLookupValue("A 32-bit integer that specifies the ID of the lookup field", "A string that contains the value of the lookup field");
        // Submit your Item
        item.Update();
        web.AllowUnsafeUpdates = false;
    }
}

GET SPLOOKUP FIELD (SINGLE-VALUE) USING SSOM C#

using(SPSite site = SPContext.Current.Site) {
    using(SPWeb web = site.OpenWeb()) {
        // Get The SPList
        SPList list = web.Lists["List Name"];
        // Get a list item By ItemID
        SPListItem item = list.GetItemById("A 32-bit integer that specifies the ID of List Item");
        //Get Lookup Field - Single Value
        SPFieldLookupValue SingleValue = new SPFieldLookupValue(item["The Lookup Field Name"].ToString());
        int SPLookupID = SingleValue.LookupId;
        string SPLookupValue = SingleValue.LookupValue;
    }
}

DOWNLOAD

You can download the full solution at SharePoint Lookup Field Operations via SSOM C#.

CONCLUSION

In this article, I have explained how to get and set SharePoint lookup field (single/multiple) values programmatically via Server Side Object Model in C#.