Crochet Diagonal Stripe & Colour Changes

I've had some questions about how I achieved the stripe on my Hook Monster crochet case. I think the easiest way to explain it would be to draw a chart, so here it is!

As this project was crocheted in the round, so the pattern is worked from right to left each row.

In each row, the colour for the stripe is worked into the second coloured stitch from the row before. The main colour is carried between the stitches and the working yarn at the back. The second colour is left attached and is picked up again on the next round.

To ensure even colouring in your stitches, there is a trick when changing colours. I'll do my best to explain this in words, but I can feel a photo or video tutorial coming on :)
While working the last stitch in the main colour, change to the second colour before pulling the last loop through. So, for an SC stitch you would have a loop on your hook in the main colour, insert hook into the working stitch and YO with main colour and pull through. You now have two loops on the hook in the main colour. Now, yarn over with the new colour and pull through the two loops. Continue working as many coloured stitches as required and use the same method to change back to the main colour.