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

public class LayoutForm:
    System.Windows.Forms.Form

{
    public LayoutForm() : base()
    {        
        InitializeComponent();
    }

    internal System.Windows.Forms.Button Button1;
    internal System.Windows.Forms.Button Button2;
    internal LayoutControl LayoutControl1;
    internal System.Windows.Forms.Button Button3;

    private void InitializeComponent()
    {
        this.Button1 = new System.Windows.Forms.Button();
        this.Button2 = new System.Windows.Forms.Button();
        this.Button3 = new System.Windows.Forms.Button();
        this.LayoutControl1 = new LayoutControl();
        this.SuspendLayout();
        this.Button1.Location = new System.Drawing.Point(16, 16);
        this.Button1.Name = "Button1";
        this.Button1.Size = new System.Drawing.Size(120, 32);
        this.Button1.TabIndex = 0;
        this.Button1.Text = "Center textbox on control";
        this.Button2.Location = new System.Drawing.Point(152, 16);
        this.Button2.Name = "Button2";
        this.Button2.Size = new System.Drawing.Size(104, 32);
        this.Button2.TabIndex = 3;
        this.Button2.Text = "Shrink user control";
        this.Button3.Location = new System.Drawing.Point(96, 232);
        this.Button3.Name = "Button3";
        this.Button3.TabIndex = 5;
        this.Button3.Text = "Reset";
        this.LayoutControl1.BackColor = System.Drawing.SystemColors.ControlDark;
        this.LayoutControl1.Location = new System.Drawing.Point(72, 64);
        this.LayoutControl1.Name = "LayoutControl1";
        this.LayoutControl1.Size = new System.Drawing.Size(150, 160);
        this.LayoutControl1.TabIndex = 6;
        this.ClientSize = new System.Drawing.Size(292, 266);
        this.Controls.Add(this.Button3);
        this.Controls.Add(this.Button2);
        this.Controls.Add(this.Button1);
        this.Controls.Add(this.LayoutControl1);
        this.Name = "Form1";
        this.Text = "Form1";
        this.ResumeLayout(false);
        this.Button1.Click += new System.EventHandler(Button1_Click);
        this.Button2.Click += new System.EventHandler(Button2_Click);
        this.Button3.Click += new System.EventHandler(Button3_Click);
    }

    [System.STAThread]
    public static void Main()
    {
        Application.Run(new LayoutForm());
    }

    // This method explicitly calls raises the layout event on 
    // LayoutControl1, changing the Bounds property.
    private void Button1_Click(System.Object sender, System.EventArgs e)
    {
        LayoutControl1.PerformLayout(LayoutControl1, "Bounds");
    }

    // This resize of LayoutControl1 implicitly triggers the layout event. 
    //  Changing the size of the control affects its Bounds property.
    private void Button2_Click(System.Object sender, System.EventArgs e)
    {
        LayoutControl1.Size = new System.Drawing.Size(100, 100);
    }

    // This method explicitly calls PerformLayout with no parameters, 
    // which raises the Layout event with the LayoutEventArgs properties
    // equal to Nothing.
    private void Button3_Click(System.Object sender, System.EventArgs e)
    {
        LayoutControl1.PerformLayout();
    }
}

// This custom control has the Layout event implented so that when 
// PerformLayout(AffectedControl, AffectedProperty) is called 
// on the control, where AffectedProperty equals "Bounds" the 
// textbox is centered on the control.
public class LayoutControl:
    System.Windows.Forms.UserControl
{
    internal System.Windows.Forms.TextBox TextBox1;

    public LayoutControl() : base()
    {        
        InitializeComponent();
    }

    private void InitializeComponent()
    {
        this.TextBox1 = new System.Windows.Forms.TextBox();
        this.SuspendLayout();
        this.TextBox1.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
        this.TextBox1.Name = "TextBox1";
        this.TextBox1.TabIndex = 0;
        this.BackColor = System.Drawing.SystemColors.ControlDark;
        this.Controls.Add(this.TextBox1);
        this.Name = "LayoutControl";
        this.ResumeLayout(false);
        this.Layout += new LayoutEventHandler(LayoutControl_Layout);
    }

    // This method is called when the Layout event is fired. 
    // This happens by during the initial load, by calling PerformLayout
    // or by resizing, adding or removing controls or other actions that 
    // affect how the control is laid out. This method checks the 
    // value of e.AffectedProperty and changes the look of the 
    // control accordingly. 
    private void LayoutControl_Layout(object sender, 
        System.Windows.Forms.LayoutEventArgs e)
    {
        if (e.AffectedProperty != null)
        {
            if (e.AffectedProperty.Equals("Bounds"))
            {
                TextBox1.Left = (this.Width-TextBox1.Width)/2;
                TextBox1.Top = (this.Height-TextBox1.Height)/2;
            }
        }
        else
        {
            this.Size = new System.Drawing.Size(150, 160);
            TextBox1.Location = new System.Drawing.Point(16, 24);
        }
        TextBox1.Text = "Left = "+TextBox1.Left+" Top = "+TextBox1.Top;
    }
}