How to get the Item of a 0 based intex collection

Question

Dear all,

I have the follwoing code snipet that I try to use in order to retrive each items from a collection :

for (int i = 0, count = Items.Count; i < count; i++)
            {
				var ri = Items.GetItemAt(i) as RadialMenuItem;
				var angleDelta = 360.0 / count;
				var angleShift = ri.HalfShifted ? -angleDelta / 2 : 0;
				var startAngle = angleDelta * i + angleShift;
				var rotation = startAngle + angleDelta / 2;
				
				ri.AngleDelta = angleDelta;
				ri.StartAngle = startAngle;
				ri.Rotation = rotation;
				

					//Items[i].AngleDelta = angleDelta;
					//Items[i].StartAngle = startAngle;
					//Items[i].Rotation = rotation;
				            }

What is wierd is that the Items.GetItemAt(i) is returning NULL and my collection is containing 2 items of type RadialMenuItem.

My Items collection is of type ItemCollection from my ItemsControl.Items

How can I retriev the item from a given index position ?

Any idea ?

Thanks for help

regards

Answer 1

Are you totally 100% sure they are of type RadialMenuItem?

Because if I do:

            ItemCollection it = new ListBox().Items;
            it.Add( new object());
            it.Add(new object());
            //foreach(var x in it)
            //{
            //    Debug.WriteLine("I got one");
            //}

            for (int i = 0; i < it.Count; i++)
            {
                var x = it.GetItemAt(i) as object;
                if(x!= null)
                {
                    Debug.WriteLine("I got one");
                }
            }

Then I get two objects.

In other words.

If you cast to the right type then your code should give you 2 things.

Change your code to:

var ri = Items.GetItemAt(i);

With out the as...

Stick a breakpoint in on the line after.

See what you get out as ri.

Is it a RadialMenuItem which is uninitialized somehow, or is it something else?

.

Your for loop is a strange way to do it.

If it compiles, I can't see how that's your problem though.

Because if I do:

            for (int i = 0, count = it.Count;  i < count; i++)
       //     for (int i = 0; i < it.Count; i++)
                {
                var x = it.GetItemAt(i) as object;
                if(x!= null)
                {
                    Debug.WriteLine("I got one");
                }
            }

Then that gets me my two objects OK.

I also wonder what Items is.

If you put a break point in before your for loop, when it breaks add a quickwatch on items and check that's what you think it's supposed to be.

---

Hope that helps.

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Answer 2

>>How can I retriev the item from a given index position ?

>>Any idea ?

Use the indexer:

var ri = Items[i] as RadialMenuItem;

But your for loop looks a bit strange. You need to make sure that you are increasing the counter variable i as expected. Try this:

            int count = Items.Count;
            for (int i = 0; i < count; i++)
            {
                var ri = Items[i] as RadialMenuItem;
                var angleDelta = 360.0 / count;
                var angleShift = ri.HalfShifted ? -angleDelta / 2 : 0;
                var startAngle = angleDelta * i + angleShift;
                var rotation = startAngle + angleDelta / 2;

                ri.AngleDelta = angleDelta;
                ri.StartAngle = startAngle;
                ri.Rotation = rotation;
            }

If ri is still NULL, the Items collection doesn't contain only RadialMenuItem objects.

Hope that helps.

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