Move control either horizontally or vertically, not combination of both

Question

I was here burning the midnight oil around some lines of code trying to solve a problem.

The code bellow will setup the control to be able to move anywhere within its p

Answer 1

Here is an example. I add a scripted small Panel 'piece' to a larger Panel 'board'.

I check for a minimum delta, so that a shaky hand won't start the movement..

One flag tracks the movement, another one the direction, with '0' being 'not yet' decided.

bool pieceMoving = false;
byte pieceDirection = 0;
Point startPosition = Point.Empty;

private void AddPieceButton_Click(object sender, EventArgs e)
{
    Panel newPiece = new Panel();
    newPiece.Size = new Size(16, 16);
    newPiece.BackColor = Color.Blue;

    pan_board.Controls.Add(newPiece);

    newPiece.MouseDown += (sender2, evt) => 
           { pieceMoving = true;  pieceDirection = 0; startPosition = evt.Location; };
    newPiece.MouseUp += (sender2, evt) => 
           { pieceMoving = false; pieceDirection = 0;};
    newPiece.MouseMove += (sender2, evt) =>
    {
        int delta = 0;
        if (!pieceMoving) return;
        if (pieceDirection == 0)
        {
            int deltaX = Math.Abs(startPosition.X - evt.X);
            int deltaY = Math.Abs(startPosition.Y - evt.Y);
            delta = deltaX + deltaY;
            if (deltaX == deltaY) return;
            if (delta  < 6) return;  // some minimum movement value
            if (deltaX > deltaY) pieceDirection = 1; else pieceDirection = 2;
        }   
        // else if (delta == 0) { pieceDirection = 0; return; }  // if you like!
        Panel piece = (Panel) sender2;
        if (pieceDirection == 1) piece.Left += evt.X; else piece.Top += evt.Y;

    };

Since I have put the code in a Button click, I named the sender 'sender2' and I use it to allow for the same code being used for many pieces.