How to do pagination in couchdb using loveseat in c#

Question

I need to do page load on scroll down in my application. I am using couchdb as my back end and I found a pagination option in couchdb which I think would satisfy my issue.

The thing is I can't find any working examples for pagination anywhere. I need someone's help in making my application work with this one.

Take a look at this for reference: https://github.com/soitgoes/LoveSeat/blob/master/LoveSeat/PagingHelper.cs

This is my code. I am getting an error in the options = model.GetOptions(); line, saying "object reference not set to an instance of an object".

public List<newVO> Getdocs(IPageableModel model)
    {
        List<newVO> resultList = new List<newVO>();
        var etag = "";
        ViewOptions options = new ViewOptions();
        options = model.GetOptions();
        options.StartKeyDocId = lastId;
        options.Limit = 13;
        options.Skip = 1;
        var result = oCouchDB.View<newVO>("GetAlldocs", options);
        //model.UpdatePaging(options, result);
        if (result.StatusCode == HttpStatusCode.NotModified)
        {
            response.StatusCode = "0";
            return null;
        }
        if (result != null)
        {
            foreach (newVO newvo in result.Items)
            {
                resultList.Add(newvo );
            }
        }

        return resultList;

    }

Thanks in advance. All ideas are welcome.

---

public List<newVO> Getdocs(IPageableModel model)
        {
            List<newVO> resultList = new List<newVO>();
            var etag = "";
            ViewOptions options = new ViewOptions();
            options = model.GetOptions();
            options.StartKeyDocId = lastId;
            options.Limit = 13;
            options.Skip = 1;
            var result = oCouchDB.View<newVO>("GetAlldocs", options);
            //model.UpdatePaging(options, result);
            if (result.StatusCode == HttpStatusCode.NotModified)
            {
                response.StatusCode = "0";
                return null;
            }
            if (result != null)
            {
                foreach (newVO newvo in result.Items)
                {
                    resultList.Add(newvo );
                }
            }

            return resultList;

        }

This is my code and i am getting error in "options = model.GetOptions();" line that object reference not set to an instance of an object...

Answer 1

I've not used the LoveSeat paging implementation, but you can use the Limit and Skip properties on the ViewOptions to achieve paging:

public static IEnumerable<T> GetPage(this ICouchDatabase couchDatabase,
    string viewName,
    string designDoc,
    int page,
    int pageSize)
{   
    return couchDatabase.View(viewName, new ViewOptions
    {
        Skip = page * pageSize,
        Limit = pageSize
    }, designDoc);
}

This simple extension method will get a page of data from a CouchDB view