Paul Stovell says…

I said last week I’d post Corneliu’s solution for all our “add an extra item to a data bound collection” woes. He emailed the code to me last week, but I thought I’d give it a whirl in the application we’re working on myself before I put it up here. I gave it a go today, and as any code you’d expect from a guy as bright as Corneliu, it works great.

I’ve got a C# version (by him) and a VB.NET conversion. It’s a little long to post the full files here, so here are the links:

ListControlNoneAdapter C# version
ListControlNoneAdapter Visual Basic .NET version

To make use of it, you’d do something like this:

protected override void OnLoad(EventArgs e){
    base.OnLoad(e);
    CustomerCollection customers = new CustomerCollection();
    customers.LoadAll();
  
    // Create an adapter to add the extra “None” item
    ListControlNoneAdapter adapter = new ListControlNoneAdapter();
    adapter.ListControl = customersCombo;
    adapter.NoneText = “(None)”;
    adapter.NoneValue = Guid.Empty;
    adapter.OriginalList = customers;
   
    // Bind to the adapter
    customersCombo.DisplayMember = “Name”;
    customersCombo.ValueMember = “CustomerID”;
    customersCombo.DataSource = adapter;
}

Thanks again Corneliu!

Also, if you don’t know who Corneliu is, make sure you come along to Code Camp!

Oh, and Coreneliu, get a blog!

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