Sharepoint field has not been initialized in C#

Question

I'm writing a code that will go through every list item in a sharepoint list and look for an empty field. If an empty field is found, the person responsible for the list item is notified by email.

I'm getting an error at the line val = oListItem[field.Title]; which states

The property or field has not been initialized. It has not been requested or the request has not been executed. It may need to be explicitly requested.

It seems to me that I have initialized everything before that line.

static void Main()
{
    ClientContext context    = new ClientContext("https://****");
    context.Credentials      = new NetworkCredential("****", "****");
    List oList               = context.Web.Lists.GetByTitle("TestBI");
    FieldCollection fieldcol = oList.Fields;

    context.Load(oList);
    context.Load(fieldcol);
    context.ExecuteQuery();

    ListItem oListItem = oList.GetItemById(1);
    object val = null;

    for (int i = 1; i <= 4; i++)
    {
        oListItem = oList.GetItemById(i);
        foreach (Field field in fieldcol)
        {
            val = oListItem[field.Title];
            if(val == null)
            {
                //Send e-mail
            }
        }
    }
    context.ExecuteQuery();
}

Answer 1

Welcome to SharePoint CSOM hell.

You did load your List and FieldCollection, but you also have to load each Field. In fact, you have to load every SharePoint object from which you intend to get properties.

for (int i = 1; i <= 4; i++)
{
    oListItem = oList.GetItemById(i);

    foreach (Field field in fieldcol)
    {
        context.Load(field);
        context.ExecuteQuery();
        val = oListItem[field.Title];
        if(val == null)
        {
            //Send e-mail
        }
    }
}