更新查询项lookup value in list using CSOM

public void UpdateLookup(string siteUrl, int id, string lookupColumnName,
List multiLookupValues, string listName, string lookupListName)
{
    using (ClientContext ctx = new ClientContext(siteUrl))
    {
        ctx.Credentials = new NetworkCredential(_username, _password, _domain);
        var list = ctx.Web.Lists.GetByTitle(listName);
        var item = list.GetItemById(id);
        var lookUpList = ctx.Web.Lists.GetByTitle(lookupListName);
        CamlQuery query = new CamlQuery();
        query.ViewXml = CreateCaml(multiLookupValues);
        var items = lookUpList.GetItems(query);
        ctx.Load(item, i => i[lookupColumnName]);
        ctx.Load(items);
        ctx.ExecuteQuery();
        var lookupValues = new ArrayList();
        FieldLookupValue[] values = item[lookupColumnName] as FieldLookupValue[];
        foreach (ListItem listItem in items)
        {
            var lookupValue = new FieldLookupValue { LookupId = listItem.Id };
            lookupValues.Add(lookupValue);
        }
        item.ParseAndSetFieldValue(lookupColumnName, null);
        item.Update();
        item[lookupColumnName] = lookupValues.ToArray();
        item.Update();
        ctx.ExecuteQuery();
    }
}

public void UpdateLookup(string siteUrl, int id, string lookupColumnName,

List multiLookupValues, string listName, string lookupListName)

{

    using (ClientContext ctx = new ClientContext(siteUrl))

    {

        ctx.Credentials = new NetworkCredential(_username, _password, _domain);

        var list = ctx.Web.Lists.GetByTitle(listName);

        var item = list.GetItemById(id);

        var lookUpList = ctx.Web.Lists.GetByTitle(lookupListName);

        CamlQuery query = new CamlQuery();

        query.ViewXml = CreateCaml(multiLookupValues);

        var items = lookUpList.GetItems(query);

        ctx.Load(item, i => i[lookupColumnName]);

        ctx.Load(items);

        ctx.ExecuteQuery();

        var lookupValues = new ArrayList();

        FieldLookupValue[] values = item[lookupColumnName] as FieldLookupValue[];

        foreach (ListItem listItem in items)

        {

            var lookupValue = new FieldLookupValue { LookupId = listItem.Id };

            lookupValues.Add(lookupValue);

        }

        item.ParseAndSetFieldValue(lookupColumnName, null);

        item.Update();

        item[lookupColumnName] = lookupValues.ToArray();

        item.Update();

        ctx.ExecuteQuery();

    }

}

private string CreateCaml(List multiLookupValues)

{

    if (multiLookupValues.Count == 1)

    {

        return string.Format(@"

 

                {0}

 

          ", multiLookupValues[0]);

    }

    StringBuilder sb = new StringBuilder();

    sb.Append(@"

 

                            ");

 

    foreach (string multiLookupValue in multiLookupValues)

    {

        sb.Append(string.Format(@"

 

                 {0}

                  ", multiLookupValue));

    }

    sb.Append(@"

 

                 ");

    return sb.ToString();

}