c# 在打开一个窗体的同时关闭本窗体(以vs2005为例)

 在Program.cs中加入---
static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            frmlogin f = new frmlogin();//初始化定义登录窗体frmlogin
            f.ShowDialog();
            if (frmlogin.b == true)
            {

                Application.Run(new frmmain());
            }
            else if (frmlogin.b == false)
            {
                Application.Run(new frmlogin());
            }
        }
在frmlogin中：
public static bool b = false;
bool c = false;

 private void button1_Click(object sender, EventArgs e)//登录
{
  frmlogin.b = true;
  c = true;
  Close();
}
 private void button2_Click(object sender, EventArgs e)
        {
            //关闭窗体
            if (MessageBox.Show("真的要退出系统吗？", "提示：", MessageBoxButtons.OKCancel, MessageBoxIcon.Information) == DialogResult.OK)
            {
                c = true;
                Application.Exit();

            }
            else
            {

            }

        }

        private void frmlogin_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (c == false)
            {
                e.Cancel = true;
            }
        }