触发新窗体创建后，当再次按下创建按钮后想弹出个消息告诉用户窗体已经创建，该怎么做呢？请教各位高人！！感谢

我用tag实现的，不知道有没有更好的方法。

using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Threading;
 
namespace test
{
    public partial class Form1 : Form
    {
        Form newForm;
 
        public Form1()
        {
            InitializeComponent();
            newForm = new Form();
            newForm.Tag = false;
            newForm.FormClosed += new System.Windows.Forms.FormClosedEventHandler(newForm_FormClosed);
        }
 
        private void ThreadProc()
        {
            newForm.Tag = true;
            newForm.ShowDialog();  
        }
 
        private void button1_Click(object sender, EventArgs e)
        {
            if (false == (bool)newForm.Tag)
            {
                Thread t = new Thread(new ThreadStart(ThreadProc));
                t.Start();
            }
            else
            {
                MessageBox.Show("Already created");
            }
        }
 
        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {
 
        }
 
        private void newForm_FormClosed(object sender, FormClosedEventArgs e)
        {
            newForm.Tag = false;
        }
    }
}

加一个变量，当新窗体创建后，将这个变量变为true，窗体关闭将这个变量变为false.
单击按钮，判断一下这个变量是否为true，如果是弹出消息告诉用户已经创建。

还是用tag通用一些，用标志位变量只能在变量所在类起作用

非常感谢！tag还是不错的方法