如何从另一个Mdi子表单中显示（Bringtofront）已经打开的Mdi子表单？

Question

在我的应用程序中，我有4个表单，form1是一个mdi容器，其余表单是它的子容器，在form1中，我正在其load事件中打开所有子表单。 在子form2中，我有一个将切换到childform3的按钮。我的问题是如何从childform2中的按钮显示childform3（已打开）

               form1:

               Form2 formchild1;
               Form3 formchild2;
               Form4 formchild3;

        private void Form1_Load(object sender, EventArgs e)
        {


        if (formchild2 == null)
        {
            formchild2 = new Form3();
        }
        formchild2.MdiParent = this;
        formchild2.Dock = DockStyle.Fill;
        formchild2.Show();
        //formchild2.BringToFront();


        if (formchild3 == null)
        {
            formchild3 = new Form4();
        }
        formchild3.MdiParent = this;
        formchild3.Dock = DockStyle.Fill;
        formchild3.Show();


        if (formchild1 == null)
        {
            formchild1 = new Form2();
        }
        formchild1.MdiParent = this;
        formchild1.Show();
        formchild1.Dock = DockStyle.Fill;
        formchild1.BringToFront();


        }


        form2:

        Form3 formchild2;
   private void button1_Click(object sender, EventArgs e)
    {
        //what i have to write hare..
            //formchild2 = new Form3();
            //formchild2.MdiParent = this.ParentForm;

            //formchild2.Dock = DockStyle.Fill;
            //formchild2.Show();
            //formchild2.BringToFront();

    }

Answer 1

创建form2时（请更改变量名，花了一段时间才发现formchild1实际上是form2），您需要实例化form2实例。

if (formchild1 == null)
{
    formchild1 = new Form2(/*Either pass in a Form3 here*/);
}
formchild1.formChild2 = formchild2; //Or make formChild2 public member
formchlid1.SetForm(formChild2); //Or make a method that sets it
formchild1.MdiParent = this;
formchild1.Show();
formchild1.Dock = DockStyle.Fill;
formchild1.BringToFront();

然后再次显示它，你可以做

formchild2.BringToFront();

Answer 2

childform3 childform3=new childform3;

private void button1_Click(object sender, EventArgs e)
    {
        if (!childform3.IsDisposed)
            childform3.Select();
        else
            childform3= new frmSearch();
        childform3.MdiParent = ParentForm;
        childform3.Show();
    }