how to make uniformgrid vertically

I'm a bit late to the party - but for anyone else searching for a solution, the following works.

<UniformGrid Columns="1" />

The WPF UniformGrid layout is horizontal only, e.g.:

1 2 3
4 5 6
7 8 9

Perhaps you could use a WrapPanel instead and just set the ItemHeight and ItemWidth to your desired grid size and set the Orientation to Orientation.Vertical.

Or you could create a derived UniformGrid to handle Orientation, there is a good example on MSDN.

This one will display:

1 4 7
2 5 8
3 6 9

Is this what you mean?