// This example uses the Parent property and the Find method of Control to set
// properties on the parent control of a Button and its Form. The example assumes
// that a Button control named button1 is located within a GroupBox control. The 
// example also assumes that the Click event of the Button control is connected to
// the event handler method defined in the example.
private void button1_Click(object sender, System.EventArgs e)
{
   // Get the control the Button control is located in. In this case a GroupBox.
   Control control = button1.Parent;
   // Set the text and backcolor of the parent control.
   control.Text = "My Groupbox";
   control.BackColor = Color.Blue;
   // Get the form that the Button control is contained within.
   Form myForm = button1.FindForm();
   // Set the text and color of the form containing the Button.
   myForm.Text = "The Form of My Control";
   myForm.BackColor = Color.Red;
}

//引入命名空间
using System;
using System.Drawing;
using System.Windows.Forms;

public class ControlParent : Form
{
  private Button btn;

  public ControlParent()
  {
    btn = new Button();
    btn.Location = new Point(50,50);
    btn.Size = new Size(100,23);
    btn.Text = "Relationships";

        //Controls.Add(btn);
    btn.Parent = this;

    MessageBox.Show("Button Parent:  " + btn.Parent.ToString() + "\n" +
      "Button HasChildren:  " + btn.HasChildren.ToString() + "\n" + 
      "TopLevelControl:  " + btn.TopLevelControl.ToString() + "\n" + 
      "Form HasChildren:  " + this.HasChildren.ToString() + "\n" + 
      "Form Controls Count:  " + this.Controls.Count.ToString(),
      "Button Relationships");
  }

  static void Main() 
  {
    Application.Run(new ControlParent());
  }
}