无法访问已释放的对象！！！！！

[boloverr]

以下是form1的代码：
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 _20080517S2
{
public partial class MainForm : Form
{
From2 fa;
public MainForm()
{
InitializeComponent();
fa = new From2();
fa.MdiParent = this;
fa.WindowState = FormWindowState.Maximized;
fa.button1.Click += new EventHandler(button1_Click);

}

void button1_Click(object sender, EventArgs e)
{
MessageBox.Show(fa.Timu);
fa.Close();


}

private void 增加题目ToolStripMenuItem_Click(object sender, EventArgs e)
{
fa.Show();
}
}
}


下面是form2的代码：
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 _20080517S2
{
public partial class From2: Form
{
public From2()
{
InitializeComponent();
}
public string Timu
{
get { return this.textBox1.Text; }
}
public string XX1
{
get { return this.textBox2.Text; }
}
public string XX2 {
get { return this.textBox3.Text; }
}
public string XX3 {
get { return this.textBox4.Text; }
}
public string XX4 {
get { return this.textBox5.Text; }
}

private void button1_Click(object sender, EventArgs e)
{
MessageBox.Show(this.Timu);

}
}
}


第一次点击”增加题目“时 form2 正常SHOW出来！

输入完后 点FORM2的Button1关闭

然后第二次点击“增加题目”的时候就会出现 “无法访问已释放的对象” 的错误

为什么会这样

环境：VS2008

[changjiangzhibin]

调试 可看到 fa.IsDispose为 true;

[vrhero]

fa.Close();

改为...

fa.Hide();

[csr_hema]

窗体关闭时是不是对象默认释放了啊？

[fb13579]

没错。对象已经释放了。

[stcsk1226]

修改这个：

void button1_Click(object sender, EventArgs e)
{
MessageBox.Show(fa.Timu);
fa.Hide();


}

或者

private void 增加题目ToolStripMenuItem_Click(object sender, EventArgs e)
{
if(fa==null)
{
fa = new From2();
}
fa.MdiParent = this;
fa.WindowState = FormWindowState.Maximized;
fa.button1.Click += new EventHandler(button1_Click);
}

[lwgboy]

也算是一种办法！
http://lwgboy.space.mofun.cc