How to asynchronously populate a field in an ObjectListView

Question

I am using an ObjectListView and trying to figure out how to correctly populate a field/column data asynchronously.

ObjectListView uses the concept of an "AspectSetter" which allows you to provide the content of the row's field data like so:

tlist.GetColumn(0).AspectGetter = delegate(Person x) { return x.Name; };

In my case, the field I am returning takes some time to calculate:

tlist.GetColumn(0).AspectGetter = delegate(Person x) { return SomeCalculation(); };

What would be the best approach to return the field data without blocking the UI and also allow the rest of the field data to be populated?

Answer 1

Create an async method to perform the calculation and return the result.

private async Task<string> CalculateAsync(Person person)
{
    // Simulate a delay, replace with your actual asynchronous operation.
    await Task.Delay(TimeSpan.FromSeconds(2));

    // Perform your actual calculation here.
    string result = "Result";

    return result;
}


tlist.GetColumn(0).AspectGetter = delegate(Person x)
{
    // Use Task.Run to run the async method on a background thread.
    return Task.Run(async () =>
    {
        string result = await CalculateAsync(x);

        // Use Invoke or BeginInvoke to update the UI on the main thread.
        tlist.Invoke((Action)(() =>
        {
            // Update the ObjectListView with the calculated result.
            tlist.RefreshObject(x);
        }));

        return result;
    });
};

In the above code the calculation is performed on a background thread, preventing it from blocking the UI, and the ObjectListView is updated with the result on the UI thread when the calculation is completed.