//窗体第一次出现时
private void Cat_Shown(object sender, EventArgs e)
{
if (welcome == null)
{
welcome = WelCome.getInstance();
welcome.Show();
}
}
//首页
private void toolStripMenuItem1_Click(object sender, EventArgs e)
{
Form active = this.ActiveMdiChild;
if (active != null)
{
active.Dispose();
}
if (welcome == null || welcome.IsDisposed)
{
welcome = WelCome.getInstance();
welcome.Show();
}
}
