C# 检查对象是否越界 (GUI)

我正在C# WFA中创建一个移动矩形。它可以毫无问题地移动，但它可能会离开我的 GUI，所以我需要检查我的矩形是否超出界限。我已经试过了，但它只适用于左上角。感谢您的帮助（我的窗口是400x400）

    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Text;
    using System.Windows.Forms;
    namespace Object
    {
        public partial class Form1 : Form
        {
            enum Directions { Left, Right, Up, Down }
            Directions _direct;
            private int _x;
            private int _y;
            public Form1()
            {
                InitializeComponent();
                _x = 50;
                _y = 50;
                _direct = Directions.Down;
            }
        private void Form1_Load(object sender, EventArgs e)
        {
            Invalidate();
        }
        private void form_paint(object sender, PaintEventArgs e)
        {
            e.Graphics.FillRectangle(Brushes.Black, _x, _y, 70, 70);
        }
        private void timer1_Tick(object sender, EventArgs e)
        {
            if (_direct == Directions.Left)
            {
                _x -= 10;
                checkPosition(_x, _y);
            }
            else if (_direct == Directions.Right)
            {
                _x += 10;
                checkPosition(_x, _y);
            }
            else if (_direct == Directions.Down)
            {
                _y += 10;
                checkPosition(_x, _y);
            }
            else if (_direct == Directions.Up)
            {
                _y -= 10;
                checkPosition(_x, _y);
            }
            Invalidate();
            checkPosition(_x, _y);
        }
        private void Form1_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Left)
            {
                _direct = Directions.Left;
            }
            else if (e.KeyCode == Keys.Right)
            {
                _direct = Directions.Right;
            }
            else if (e.KeyCode == Keys.Up)
            {
                _direct = Directions.Up;
            }
            else if (e.KeyCode == Keys.Down)
            {
                _direct = Directions.Down;
            }
        }
        private void checkPosition(int x, int y) {
            if (x < 0) {
                _x = 0;
            }
            else if (y < 0) {
                _y = 0;
            }
            else if ((x + 70) > 400) { _x = 330; }
            else if ((y+70)>400) {_y=330;}
        }
    }
}

// rectangle is your rectangle
bool outOfBounds=!(Rectangle.Intersect(ClientRectangle, rectangle).Equals(rectangle))