关于linq的几个小例子

 private void button1_Click(object sender, EventArgs e)
        {
            int[] numbers = new int[7] { 0,1,2,3,4,5,6};
            var result0 = from num in numbers
                          where (num % 2 == 0)
                          select num;
            foreach (int n in result0)
            {
                listBox1.Items.Add(n);
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            listBox1.Items.Clear();
            int[] numbers = new int[7] { 2,3,2,4,3,5,5};
            var result1 = from num in numbers
                          where num > 3
                          orderby num descending
                          select num;
            foreach (int n in result1)
            {
                listBox1.Items.Add(n);
            }
        }

        private void button3_Click(object sender, EventArgs e)
        {
            listBox1.Items.Clear();
            int[] numbers = new int[7] { 2, 3, 2, 4, 3, 5, 5 };
            var result2 = from num in numbers
                          where num > 3
                          orderby num ascending
                          select string.Format("当前值为{0}",num) ;
            foreach (string  n in result2)
            {
                listBox1.Items.Add(n);
            }
        }

        private void button4_Click(object sender, EventArgs e)
        {
            listBox1.Items.Clear();
            int[] numbers = new int[7] { 2, 3, 2, 4, 3, 5, 5 };
            int  result3 = (from num in numbers
                           where num > 3
                           select num).Count();
            button4.Text += "--" + result3.ToString();
        }