Custom sort with FastObjectListview is not working.

Question

Hey, I'm using the FastObjectListview and now I need to sort on 2 columns. So I tried using the example I found on the ObjectListview website but I can't get it to work.

class MyCustomSortingDataSource : FastVirtualListDataSource
{ 
    override public void SortObjects(OLVColumn column, SortOrder order) { 
        // do some amazing sorting here 
        this.RebuildIndexMap(); // you must call this otherwise the control will not work properly 
    }; 
}; 
...
this.myFastObjectListView.DataSource = new MyCustomSortingDataSource(this.myFastObjectListView);

first of all I added:

using BrightIdeasSoftware;

but that namespace doesn't contain the FastVirtualListDataSource it contains a FastObjectListDataSource.

in the FastObjectListDataSource however there is no SortObjects method to override, there's a Sort method which I guess I should be overriding instead.

So this is what I got instead of the sample code:

class MyCustomSortingDataSource : FastObjectListDataSource 
{
    public MyCustomSortingDataSource(FastObjectListView listView) 
        : base(listView) 
    {
    }

    public override void Sort(OLVColumn column, SortOrder sortOrder) 
    {
        base.Sort(column, sortOrder); 
        // do some amazing sorting here
        // base.ObjectList.Sort(new ModelObjectComparer(this.olvGroupCln, SortOrder.Ascending, column, sortOrder));
        this.RebuildIndexMap(); // you must call this otherwise the control will not work properly 
    }
}

I can't access the olvGroupCln which is the first column I need to sort on, after sorting that column I need to sort the column the user clicked on.

Some help would be gladly appreciated.

Thanks in advance.

Answer 1

That's always the problem with documentation -- it's never quite up to date. I'll fix the docs.

I guess you can't access your olvGroupCln variable because it is on the form itself, and you need it within the sorter? Is that right?

Just give your custom sorter a property that holds the column you want to sort by. Whenever you set olvGroupCln, set the property on your sorter too. Something like this

class MyCustomSortingDataSource : FastObjectListDataSource
{
    public MyCustomSortingDataSource(FastObjectListView listView)
        : base(listView) { }

    public OLVColumn SortColumn {
        get { return this.sortColumn; }
        set { this.sortColumn = value; }
    }
    private OLVColumn sortColumn;

    public override void Sort(OLVColumn column, SortOrder sortOrder)
    {
        if (sortOrder != SortOrder.None) {
            ArrayList objects = (ArrayList)this.listView.Objects;
            objects.Sort(new ModelObjectComparer(this.SortColumn, SortOrder.Ascending, column, sortOrder));

        }
        this.RebuildIndexMap();
    }
}