c# 判断窗体已打开则显示为焦点

c# 判断窗体已打开则显示为焦点 

MDI编程模式



private void menuItem3_Click(object sender, System.EventArgs e) //菜单的CLICK事件.

  {

   FrmClass MyClass = null; //生成自己的表单

   foreach( Form ftemp in this.MdiChildren) //查找当前父表单所有子表单

   {

    if(ftemp is FrmClass)

    {

     MyClass = (FrmClass)ftemp;

     break;

    }

   } 

   if(MyClass==null || MyClass.IsDisposed)

   {

    MyClass = new FrmClass();

    MyClass.MdiParent = this;

   }

   MyClass.Show();

   MyClass.Activate();



  } 



普通显示模式：



private void lblCopyRight_Click(object sender, EventArgs e)

        {

            Form2 frm = null;

            foreach (Form frmt in Application.OpenForms)

            {

                if (frmt is Form2)

                {

                    frm = (Form2)frmt;

                    break;

                }

            }

            if (frm == null)

                (new Form2()).Show();

            else

            {

                frm.Show();

                frm.Activate();

            }

        }

注：该文是摘自 http://www.cnblogs.com/vic_lu/archive/2011/05/20/2052016.html