How to detect a dragging event?

My goal here is to give you some ideas, and a smidgen of code, that I hope will help you write the game yourself.

A quick sketch of strategies for monitoring the mouse movement during the game. I'll assume:

0. you define the variance threshold the determines how far the mouse can vary on the horizontal and vertical axes when the game is being played. in a variable of type int: 'threshold

1. you'll record the initial mouse down x,y position in variables mdX, and mdY, and the final mouse-position on mouse-up in muX, and muY.

1.a. you'll create a boolean flag to indicate if the current game is being played vertically, or horizontally: isUpDown

1.b. you'll create a boolean flag to indicate if the current game is over: isGameOver

1.c. you'll create a boolean flag to indicate if mouse is up: isMouseUp

1.d. you'll record the DisplayRectangle of the PictureBox in the variable 'pictureRectangle

2. you'll write an end of game function called 'gameOver(boolean completionState that gets called whenever the game ends, and, if 'completionState is true, you'll do what you need to do figure out if the user won; if 'completionState is false, the game is lost.

3. I assume there are three ways the user can lose the game:

a. moving the mouse outside the PictureBox while the Mouse is down and the game is in play.

b. moving the mouse too far right or left in the horizontal axis when the game is being played down-up, or up-down

c. moving the mouse too far up or down in the vertical axis when the game is being played left-right, or right, left

private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
    // ignore mouse events if the game is not in play, or is over
    if (isMouseUp || isGameOver) return;

    // is the mouse now outside the PictureBox ?
    if (! pictureRectangle.Contains(e.Location)) gameOver(false);

    // tolerance testing code goes here ...
    if (isUpDown)
    {
        // test for horizontal variance
        if (Math.Abs(mdX - e.X) > threshold) gameOver(false);
    }
    else
    {
        // test for vertical variance
        // for you to write
    }
}

Here's a quick (again, deliberately incomplete) sketch of how you might structure the 'gameOver function:

private void gameOver(bool completionState)
{
    isGameComplete = true;
    isGameOver = true;

    bool isAWin = false;

    if (completionState)
    {
        // left for you to write
        // possible win
        // isAWin = true ... if ... for you to figure out
    }

    // status report
    if(isAWin)
    {
        // left for you to write
        // definite win
    }
    else
    {
       // left for you to write
       // definite loss
    }
}

Each of the mouse events passes you a MouseEventArgs parameter which provides you the Location property to find where the mouse was when the event was fired. If you compare this to teh previous location, you know in which direction it has moved.

If the mouse leaves the PictureBox, you will no longer get the events in the PictureBox handlers...