标签页添加表单等控件时，如何设置表单所有者

Question

当我个人将两个 forms 添加到两个页面控件时，如何设置表单所有者？ 由于所有者为空，无法将表单事件中的数据设置为另一个表单的文本框文本，如何处理，请帮助我。

-main form- //标签页添加控件

private void TestForm2_Shown(object sender, EventArgs e)
{
    //var DataUpdate = new DataUpdate();
    var DataUpdate = new TestForm3();
    DataUpdate.TopLevel = false;
    //DataUpdate.Visible = true;
    //DataUpdate.Top = 0;
    //DataUpdate.Left = 0;
    DataUpdate.Dock = DockStyle.Fill;
    DataUpdate.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
    tabPage1.Controls.Add(DataUpdate);


    //var SystemSetting = new SystemSetting();
    var SystemSetting = new TestForm4();
    SystemSetting.TopLevel = false;
    //SystemSetting.Visible = true;
    //SystemSetting.Top = 0;
    //SystemSetting.Left = 0;
    SystemSetting.Dock = DockStyle.Fill;
    SystemSetting.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
    tabPage2.Controls.Add(SystemSetting);
    SystemSetting.Show();
}

Answer 1

// In your TestForm3, 
private void button1_Click(object sender, EventArgs e)
{
  TestForm4 frm = new TestForm4();
  frm.owner=this;
  frm.Show();
}
 // In your TestForm4,
private void button1_Click(object sender, EventArgs e)
{
  TestForm3 mainForm=(TestForm3)this.owner;
  mainForm.LabelText = textBox1.Text;
}