Set lookupfield value on document upload through event receiver

Question

I have a custom list, where when I create a new item, I assign a custom id to that element through an event receiver. After the item is created, I create a file that I upload to a document library. This document is supposed to be connected to the custom list through a lookupfield. The lookupfield is the same as the custom id i created on itemadded.

When i upload the file I am able to set all the fields, except the lookupfield. How can i select a specific lookupvalue for my document?

The event receiver is bound to a specific list with <Receivers ListUrl="Lists/CustomList">

This is how i update the item on ItemAdded.

public override void ItemAdded(SPItemEventProperties properties)
{
    base.ItemAdded(properties);
    SPListItem element = properties.ListItem;
    //Just to set my custom value
    int itemId = properties.ListItemId;
    int customId = itemId+10000;
    element["Title"] = customId;

    element.Update();

In the same eventreceiver,within the ItemAdded method, I do the following to upload the document and set its values:

SPSite site = new SPSite("http://localhost");
        SPWeb web = site.OpenWeb();
        web.AllowUnsafeUpdates = true;
        SPFolder Documentlibrary = web.Folders["Documentlibrary"];
        Boolean replaceExistingFiles = true;
        String filename = "C:\\files\\" + customId + ".jpeg";
        String name = customId+ ".jpeg";
        FileStream upload= File.OpenRead(filename);
        SPFile spfile = Documentlibrary.Files.Add(name, upload, replaceExistingFiles);

        SPList docAsList = web.Lists["Documentlibrary"];
        SPListItem itemJustAdded = docAsList.GetItemById(spfile.ListItemAllFields.ID);
        itemJustAdded["Title"]= customId;            
        itemJustAdded["Cat"] = "cat1";
        //This here is the lookupvalue I want to set.
        itemJustAdded["CustomID"] = customId;

        itemJustAdded.Update();
        web.AllowUnsafeUpdates = false;
        web.Close();
        site.Close();

Ok, so I'm guessing that the issue is with my assignment in the line: itemJustAdded["CustomID"] = customId; However I don't know how to select the correct value, could i use element.ID for example?

Im really hoping someone can shed some light on this for me, maybe some best practice. Thanks in advance.

Answer 1

If you want to set a SPFieldLookupValue you have to create one first and then you can set this in your item field.

Like this:

SPFieldLookupValue newValue = new SPFieldLookupValue(itemId,customId);
itemJustAdded["CustomID"] = newValue;