I'm working on programming a Tetris game in Visual C# 2005. This is the most extensive program I have designed yet.

I create a shape class and a block class to control the location, movement, and display of the different Tetris pieces. I have moveDown(), moveLeft(), and moveRight() functions for each shape (and corresponding canMoveDown(), canMoveLeft(), canMoveRight() boolean functions that verify it's ok to move). This is all working beautifully.

I want to use the down, right, and left arrow keys to let the user move the block around, in addition to using a timer to have the shape automatically fall one row every so many milliseconds.

I am using the KeyDown event handler to check when the user presses the down, left, and right arrow key. This isn't so hard. The problem is that I want to allow for diagonal motion, and I want it work as smoothly possible. I have tried a bunch of different ways of approaching this problem, with varying levels of success. But I can't get it quite right...

My most successful approach was to use three boolean variables to keep track of when the down, left, and right arrow keys are being held down. I would set the booleans to true in the KeyDown event, and to false in the KeyUp event. In the KeyDown event I would also tell the block how to move, using the boolean variables to check which combination was currently being pressed. It worked really well, except for one thing.

If I pressed one of the arrow keys and held, then pressed a second arrow key and then released the second key, the block would stop moving altogether, instead of continuing to move in the direction of the first arrow key which hasn't been released yet. I think this is because the second key triggered the KeyDown event, and upon its release the KeyUp event was fired, and the KeyDown event stopped firing completely, even though the first key is fired.

I cannot for the life me of find a satisfactory solution to this problem.

Any help would be greatly appreciated =)