Determine the shape of multiple selected cells within a data grid

I'm using the Infragistics UltraWinGrid to present some data. I ne开发者_开发知识库ed some Excel copy/paste functionality. That's the easy bit.

1. What I want to do is determine the shape of the selection, and ensure it's a rectangle of adjacent cells. If it's not, an error is to be shown (as pasting said data will just lead to errors).

2. I then need to detect all the boundary edge cells so I can put a "you've copied this" border around the cells, ala Excel.

I'm hoping to achieve this by comparing a list of Point structures or something along those lines.

To illustrate the problem better, here are some pictures:

1. This is fine, see the edge cells (duh)

2. This won't work, I've tried to copy too much, show an error

3. The user hasn't learnt by now that this just won't work. You can even see where I've copied the "wrong" cell out of sheer lazyness.

I've got a Dictionary of Points and Cells, ready to work with. Any ideas? C#/VB is fine.

UPDATE: This might help?

Taking the second diagram:

0,0 1,0 2,0
0,1 1,1 2,1
0,2 1,2 2,2
0,3 1,3 2,3
    1,4     <<< wrong

Thanks, Tom

Ok I've had a good think about this and GertArnold has pointed me in the right direction, simply by saying "range of cells with a hole in it allowed?"

This is what happens when you spend 6 months not coding or problem solving, due to massive paperwork and auditing requirements, you forget how to even begin a simple algorithm.

It's so easy it hurts. Firstly I get the cells from the datasheet and reformat them so they're based at zero (as opposed to their actual position on the grid). I do this by simply negating the value of the cell at {0,0} and applying this to all the cells.

To calculate the gaps, do this:

Private Function HasGapsInCells(points As List(Of CellPoint)) As Boolean

    Dim colCount As Integer = points.GroupBy(Function(x) x.Column).Count()
    Dim rowCount As Integer = points.GroupBy(Function(x) x.Row).Count()

    For row As Integer = 0 To rowCount - 1
        Dim rowL As Integer = row
        For col As Integer = 0 To colCount - 1
            Dim colL As Integer = col
            If Not points.Exists(Function(x) x.Row = rowL And x.Column = colL) Then
                Return True '-- There are gaps'
            End If
        Next
    Next

    Return False

End Function

So easy.