扩展SplitContainer控件

using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
[ToolboxBitmap(typeof(SplitContainer))]
public partial class SplitContainerEx : SplitContainer
{
#region Field

/// <summary>
/// 控制器绘制区域
/// </summary>
private Rectangle ControlRect
{
get
{
var rect = new Rectangle();

if (Orientation == Orientation.Horizontal)
{
rect.X = Width <= 80 ? 0 : Width / 2 - 40;
rect.Y = SplitterDistance;
rect.Width = 80;
rect.Height = 9;
}
else
{
rect.X = SplitterDistance;
rect.Y = Height <= 80 ? 0 : Height / 2 - 40;
rect.Width = 9;
rect.Height = 80;
}
return rect;
}
}

/// <summary>
/// 鼠标状态(进入或离开)
/// </summary>
private MouseState _mouseState = MouseState.Normal;

/// <summary>
/// 定义折叠或展开的是哪一个面板
/// </summary>
private SplitterPanelEnum _collpaseOrExpandPanel;

/// <summary>
/// Splitter是否固定
/// </summary>
private bool _isSplitterFixed = true;

/// <summary>
/// 当前是否为折叠状态
/// </summary>
private bool _collpased;

#endregion

#region Property

/// <summary>
/// 进行折叠或展开的SplitterPanel,设置为属性，所以可以在页面进行重新设置
/// </summary>
[DefaultValue(SplitterPanelEnum.Panel1)]
public SplitterPanelEnum CollpaseOrExpandPanel
{
get
{
return _collpaseOrExpandPanel;
}
set
{
if (value != _collpaseOrExpandPanel)
{
_collpaseOrExpandPanel = value;
Invalidate(ControlRect);
}
}
}

/// <summary>
/// 设定Panel1是否为默认折叠
/// </summary>
private bool _panel1Collapsed;
[DefaultValue(false)]
public new bool Panel1Collapsed
{
get
{
return _panel1Collapsed;
}
set
{
//只有当CollpaseOrExpandPanel = Panel时，Panel1Collapsed的设置才会有效
if (CollpaseOrExpandPanel == SplitterPanelEnum.Panel1 && value != _panel1Collapsed)
{
_panel1Collapsed = value;
//设置_collpased值为value的相反值，再调用CollpaseOrExpand()进行折叠或展开.
_collpased = !value;

CollpaseOrExpand();
}
}
}

/// <summary>
/// 设置Panel2是否为默认折叠
/// </summary>
private bool _panel2Colapsed;
[DefaultValue(false)]
public new bool Panel2Collapsed
{
get
{
return _panel2Colapsed;
}
set
{
//只有当CollpaseOrExpandPanel = Pane2时，Panel1Collapsed的设置才会有效
if (CollpaseOrExpandPanel == SplitterPanelEnum.Panel2 && value != _panel2Colapsed)
{
_panel2Colapsed = value;
//设置_collpased值为value的相反值，再调用CollpaseOrExpand()进行折叠或展开
_collpased = !value;

CollpaseOrExpand();
}
}
}

/// <summary>
/// 用于固定保存显式设定的SplitterDistance,因为基类的SplitterDistance属性会变动
/// </summary>
public int DefaultSplitterDistance
{
get;
set;
}

#endregion

#region Ctor

public SplitContainerEx()
{
SetStyle(
ControlStyles.UserPaint |
ControlStyles.AllPaintingInWmPaint |
ControlStyles.OptimizedDoubleBuffer, true);

Panel1MinSize = 0;
Panel2MinSize = 0;
}

#endregion

#region Override

protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);

Color color = _mouseState == MouseState.Normal ? SystemColors.ButtonShadow : SystemColors.ControlDarkDark;

//需要绘制的图片
Bitmap bmp = CreateControlImage(color);

//对图片进行旋转
RotateFlip(bmp);

//清除绘制区域
e.Graphics.SetClip(SplitterRectangle);
e.Graphics.Clear(BackColor);
//绘制
e.Graphics.DrawImage(bmp, ControlRect);
}

protected override void OnMouseMove(MouseEventArgs e)
{
//鼠标在控制按钮区域
if (SplitterRectangle.Contains(e.Location))
{
if (ControlRect.Contains(e.Location))
{
//如果拆分器可移动，则鼠标在控制按钮范围内时临时关闭拆分器
if (!IsSplitterFixed)
{
IsSplitterFixed = true;

_isSplitterFixed = false;
}

Cursor = Cursors.Hand;
_mouseState = MouseState.Hover;
Invalidate(ControlRect);
}
else
{
//如果拆分器为临时关闭，则开启拆分器
if (!_isSplitterFixed)
{
IsSplitterFixed = false;
Cursor = Orientation == Orientation.Horizontal ? Cursors.HSplit : Cursors.VSplit;
}
else
{
Cursor = Cursors.Default;
}
_mouseState = MouseState.Normal;
Invalidate(ControlRect);
}
}
base.OnMouseMove(e);
}

protected override void OnMouseLeave(EventArgs e)
{
Cursor = Cursors.Default;

_mouseState = MouseState.Normal;

Invalidate(ControlRect);

base.OnMouseLeave(e);
}

protected override void OnMouseClick(MouseEventArgs e)
{
if (ControlRect.Contains(e.Location))
{
CollpaseOrExpand();
}

base.OnMouseClick(e);
}

#endregion

#region Method

/// <summary>
/// 折叠或展开
/// 1.当当前状态为折叠状态时，则进行展开操作
/// 2.当当前状态为展开状态时，则进行折叠操作
/// </summary>
private void CollpaseOrExpand()
{
//当前为缩小状态，进行Expand操作
if (_collpased)
{
//展开
SplitterDistance = DefaultSplitterDistance;
}
//当前为伸展状态，进行Collpase操作
else
{
//折叠
if (_collpaseOrExpandPanel == SplitterPanelEnum.Panel1)
{
SplitterDistance = 0;
}
else
{
if (Orientation == Orientation.Horizontal)
{
SplitterDistance = Height - 9;
}
else
{
SplitterDistance = Width - 9;
}
}
}

_collpased = !_collpased;

Invalidate(ControlRect); //局部刷新绘制
}

/// <summary>
/// 需要绘制的用于折叠窗口的按钮样式
/// </summary>
/// <param name="color"></param>
/// <returns></returns>
private Bitmap CreateControlImage(Color color)
{
var bmp = new Bitmap(80, 9);
for (int x = 5; x <= 30; x += 5)
{
for (int y = 1; y <= 7; y += 3)
{
bmp.SetPixel(x, y, color);
}
}
for (int x = 50; x <= 75; x += 5)
{
for (int y = 1; y <= 7; y += 3)
{
bmp.SetPixel(x, y, color);
}
}

int k = 0;
for (int y = 7; y >= 1; y--)
{
for (int x = 35 + k; x <= 45 - k; x++)
{
bmp.SetPixel(x, y, color);
}
k++;
}

return bmp;
}

private void RotateFlip(Bitmap bmp)
{
if (Orientation == Orientation.Horizontal)
{
if (_collpaseOrExpandPanel == SplitterPanelEnum.Panel1 && !_collpased ||
_collpaseOrExpandPanel == SplitterPanelEnum.Panel2 && _collpased)
{
bmp.RotateFlip(RotateFlipType.RotateNoneFlipX);
}
else
{
bmp.RotateFlip(RotateFlipType.Rotate180FlipX);
}
}
else
{
if (_collpaseOrExpandPanel == SplitterPanelEnum.Panel1 && !_collpased ||
_collpaseOrExpandPanel == SplitterPanelEnum.Panel2 && _collpased)
{
bmp.RotateFlip(RotateFlipType.Rotate90FlipX);
}
else
{
bmp.RotateFlip(RotateFlipType.Rotate270FlipX);
}
}
}

#endregion

#region Enums

enum MouseState
{
/// <summary>
/// 正常
/// </summary>
Normal,
/// <summary>
/// 鼠标移入
/// </summary>
Hover
}

public enum SplitterPanelEnum
{
Panel1,
Panel2
}

#endregion
}
}