public FunctionViewForm()
{
InitializeComponent();
grid = new Grid();
func = new Function(grid, functxtbox.Text);
isClicked = false;
x1 = y1 = 0;
}
Node node; //親ノード
#endregion Fields
#region Constructors
//コンストラクタ(引数：grid)
public Function(Grid grid, string firstexpression)
{
expression = firstexpression;
this.grid = grid;
node = new Node(expression);
}