Order Retrieval System with a SharePoint Backend

I have an ordering system that uses SharePoint. Below I've included a small snapshot of the system that is used in a WPF form when the user clicks a button to refresh the order listing. The outcome is a populated WPF datagrid. Note that this code is using C# 6.0 as well.

Everything works well, and it's quite quick, but I feel there's lots of room in my skill-set for improvements - happy for all guidance that can be offered!

Refresh Orders code

```
private void RefreshOrders(string loadStatus)
{
Orders.LoadStatus = loadStatus;

var collListItem = Orders.LatestOrders;

if (!collListItem.Any())
{
MessageBox.Show(
"No orders are currently within the queue.",
"Information Center",
MessageBoxButton.OK,
MessageBoxImage.Information);

return;
}

if (collListItem == null)
{
MessageBox.Show(
"Order processor was unable to reach the SharePoint server to download orders.",
"SharePoint Currently Unavailable",
MessageBoxButton.OK,
MessageBoxImage.Asterisk);

return;
}

var customers = new ObservableCollection();

foreach (var customer in
collListItem.Select(
item =>
new
{
Persona = item["Persona"].ToString(),
CustomerName = item["Title"].ToString(),
Email = item["Customer_x0020_E_x002d_mail"].ToString(),
Organization = item["Organization"].ToString(),
PhoneNumber = item["Customer_x0020_Phone_x0020_Numbe"].ToString(),
Street = item["Customer_x0020_Street"].ToString(),
Suburb = item["Customer_x0020_Suburb"].ToString(),
Postcode = item["Customer_x0020_Postcode"].ToString(),
OrderDate = Convert.ToDateTime(item["Created"], new CultureInfo("hr-HR")).Date ,
DispatchedDate = Convert.ToDateTime(item["Modified"], new Cult

Have you tested this? You've used the words 'quick' and 'SharePoint' in the same question which, in my experience, is almost always a lie :)

You have a problem here:

private void RefreshOrders(string loadStatus)
{
    Orders.LoadStatus = loadStatus;

    var collListItem = Orders.LatestOrders;

    if (!collListItem.Any())
    {
        // omitted.
    }

    if (collListItem == null)
    {

That second if statement can never be hit! If collListItem is null, then the call to Any() will throw a null reference exception.

A few quick notes on your code:

• LoadStatus should probably be an enum

• Put the column names in named constants

• A property shouldn't do non trivial work - CachedItems should be retrieved through a method

• You could remove the foreach loop to add to customers observable collection and use the constructor which takes an IEnumerable

Update

var customerQuery = collListItem.Select(
        item =>
        new
        {
            Persona = item["Persona"].ToString(),
            CustomerName = item["Title"].ToString(),
            Email = item["Customer_x0020_E_x002d_mail"].ToString(),
            Organization = item["Organization"].ToString(),
            PhoneNumber = item["Customer_x0020_Phone_x0020_Numbe"].ToString(),
            Street = item["Customer_x0020_Street"].ToString(),
            Suburb = item["Customer_x0020_Suburb"].ToString(),
            Postcode = item["Customer_x0020_Postcode"].ToString(),
            OrderDate = Convert.ToDateTime(item["Created"], new CultureInfo("hr-HR")).Date ,
            DispatchedDate = Convert.ToDateTime(item["Modified"], new CultureInfo("hr-HR")).Date,
            Status = item["Status"].ToString()
        })
        .Distinct()
        .Select(
            r =>
            new Customer
            {
                Persona = r.Persona,
                CustomerName = r.CustomerName,
                Email = r.Email,
                Organization = r.Organization,
                PhoneNumber = r.PhoneNumber,
                Street = r.Street,
                Suburb = r.Suburb,
                Postcode = r.Postcode,
                OrderDate = r.OrderDate.Date,
                DispatchedDate = r.DispatchedDate,
                Status = r.Status
            }));

var customers = new ObservableCollection(customerQuery);

StackExchange Code Review Q#101936, answer score: 3