自分自身のサイズを変更してもいいし、 FormBorderStyle.Noneの親フォームのサイズが変更されるようにすることも出来る。
using System.Drawing;
using System.Windows.Forms;
/// <summary>
/// コントロールの端をD＆Dすることによってサイズを変更出来る機能を提供するクラス
/// </summary>
class DAndDSizeChanger {
Control mouseListner;
Control sizeChangeCtrl;
DAndDArea sizeChangeArea;
Size lastMouseDownSize;
Point lastMouseDownPoint;
DAndDArea status;
int sizeChangeAreaWidth;
Cursor defaultCursor;
/// <param name="mouseListner">マウス入力を受け取るコントロール</param>
/// <param name="sizeChangeCtrl">マウス入力によってサイズが変更されるコントロール</param>
/// <param name="sizeChangeArea">上下左右のサイズ変更が有効になる範囲を指定</param>
/// <param name="sizeChangeAreaWidth">サイズ変更が有効になる範囲の幅を指定</param>
public DAndDSizeChanger(Control mouseListner, Control sizeChangeCtrl, DAndDArea sizeChangeArea, int sizeChangeAreaWidth) {
this.mouseListner = mouseListner;
this.sizeChangeCtrl = sizeChangeCtrl;
this.sizeChangeAreaWidth = sizeChangeAreaWidth;
this.sizeChangeArea = sizeChangeArea;
defaultCursor = mouseListner.Cursor;
mouseListner.MouseDown += new MouseEventHandler(mouseListner_MouseDown);
mouseListner.MouseMove += new MouseEventHandler(mouseListner_MouseMove);
mouseListner.MouseUp += new MouseEventHandler(mouseListner_MouseUp);
}
void mouseListner_MouseDown(object sender, MouseEventArgs e) {
lastMouseDownPoint = e.Location;
lastMouseDownSize = sizeChangeCtrl.Size;
//動作を決定
status = DAndDArea.None;
if(getTop().Contains(e.Location)) {
status |= DAndDArea.Top;
}
if(getLeft().Contains(e.Location)) {
status |= DAndDArea.Left;
}
if(getBottom().Contains(e.Location)) {
status |= DAndDArea.Bottom;
}
if(getRight().Contains(e.Location)) {
status |= DAndDArea.Right;
}
if(status != DAndDArea.None) {
mouseListner.Capture = true;
}
}
void mouseListner_MouseMove(object sender, MouseEventArgs e) {
//カーソルを変更
if((getTop().Contains(e.Location) &&
getLeft().Contains(e.Location)) ||
(getBottom().Contains(e.Location) &&
getRight().Contains(e.Location))) {
mouseListner.Cursor = Cursors.SizeNWSE;
} else if((getTop().Contains(e.Location) &&
getRight().Contains(e.Location)) ||
(getBottom().Contains(e.Location) &&
getLeft().Contains(e.Location))) {
mouseListner.Cursor = Cursors.SizeNESW;
} else if(getTop().Contains(e.Location) ||
getBottom().Contains(e.Location)) {
mouseListner.Cursor = Cursors.SizeNS;
} else if(getLeft().Contains(e.Location) ||
getRight().Contains(e.Location)) {
mouseListner.Cursor = Cursors.SizeWE;
} else {
mouseListner.Cursor = defaultCursor;
}
if(e.Button == MouseButtons.Left) {
int diffX = e.X - lastMouseDownPoint.X;
int diffY = e.Y - lastMouseDownPoint.Y;
if((status & DAndDArea.Top) == DAndDArea.Top) {
int h = sizeChangeCtrl.Height;
sizeChangeCtrl.Height -= diffY;
sizeChangeCtrl.Top += h - sizeChangeCtrl.Height;
}
if((status & DAndDArea.Bottom) == DAndDArea.Bottom) {
sizeChangeCtrl.Height = lastMouseDownSize.Height + diffY;
}
if((status & DAndDArea.Left) == DAndDArea.Left) {
int w = sizeChangeCtrl.Width;
sizeChangeCtrl.Width -= diffX;
sizeChangeCtrl.Left += w - sizeChangeCtrl.Width;
}
if((status & DAndDArea.Right) == DAndDArea.Right) {
sizeChangeCtrl.Width = lastMouseDownSize.Width + diffX;
}
}
}
void mouseListner_MouseUp(object sender, MouseEventArgs e) {
mouseListner.Capture = false;
}
/// <summary>
/// ポイントがD＆Dするとサイズが変更されるエリア内にあるかどうかを判定します。
/// </summary>
public bool ContainsSizeChangeArea(Point p){
return getTop().Contains(p) ||
getBottom().Contains(p) ||
getLeft().Contains(p) ||
getRight().Contains(p);
}
private Rectangle getTop() {
if((sizeChangeArea & DAndDArea.Top) == DAndDArea.Top) {
return new Rectangle(0, 0, mouseListner.Width, sizeChangeAreaWidth);
} else {
return new Rectangle();
}
}
private Rectangle getBottom() {
if((sizeChangeArea & DAndDArea.Bottom) == DAndDArea.Bottom) {
return new Rectangle(0, mouseListner.Height - sizeChangeAreaWidth,
mouseListner.Width, sizeChangeAreaWidth);
} else {
return new Rectangle();
}
}
private Rectangle getLeft() {
if((sizeChangeArea & DAndDArea.Left) == DAndDArea.Left) {
return new Rectangle(0, 0,
sizeChangeAreaWidth, mouseListner.Height);
} else {
return new Rectangle();
}
}
private Rectangle getRight() {
if((sizeChangeArea & DAndDArea.Right) == DAndDArea.Right) {
return new Rectangle(mouseListner.Width - sizeChangeAreaWidth, 0,
sizeChangeAreaWidth, mouseListner.Height);
} else {
return new Rectangle();
}
}
}
public enum DAndDArea {
None = 0,
Top = 1,
Bottom = 2,
Left = 4,
Right = 8,
All = 15
}
以下の様に使用する。
using System;
using System.Windows.Forms;
namespace WindowsFormsApplication1 {
public partial class Form1 :Form {
DAndDSizeChanger sizeChanger;
public Form1() {
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e) {
sizeChanger = new DAndDSizeChanger(this.dAndDMoveTextBox1, this,DAndDArea.All , 8);
}
}
}
C#|TextBox上でのドラッグ＆ドロップでフォームを移動するのクラスと併用するには…
using System;
using System.Windows.Forms;
namespace WindowsFormsApplication1 {
public partial class Form1 :Form {
DAndDSizeChanger sizeChanger;
public Form1() {
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e) {
sizeChanger = new DAndDSizeChanger(this.dAndDMoveTextBox1, this,DAndDArea.All , 8);
}
private void dAndDMoveTextBox1_DAndDMoving(object sender, Anis.WindowsForms.DAndDMovingEventArgs e) {
e.Cancel = sizeChanger.ContainsSizeChangeArea(e.Location);
}
}
}