//初始化子窗体
Form childb=new Basic(),childg=new Grade(),childbg=new Both();
//判断子窗体是否已打开
private void openChild(Form pform)
{
try
{
//判断窗体是否被释放,没有释放的话,则设置为当前窗体
if (!pform.IsDisposed)
{
pform.MdiParent = this;
//创建窗体句柄
pform.Show();
if (pform.WindowState == FormWindowState.Minimized)
{
pform.WindowState = FormWindowState.Normal;
}
else pform.Activate();//激活窗体句柄
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void toolStripMenuItem1_Click(object sender, EventArgs e)
{
//如果释放的话,就初始化子窗体
if (childb.IsDisposed)
{
childb = new Basic();
}
openChild(childb);
}
private void toolStripMenuItem2_Click(object sender, EventArgs e)
{
if (childg.IsDisposed)
{
childg = new Grade();
}
openChild(childg);
}
private void toolStripMenuItem3_Click(object sender, EventArgs e)
{
if (childbg.IsDisposed)
{
childbg = new Both();
}
openChild(childbg);
}