using Microsoft.Win32;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms.VisualStyles;
namespace System.Windows.Forms
{
/// <summary>
/// Interface that exposes an <c>Enabled</c> property for an item supplied to .
/// </summary>
public interface IEnableable
{
/// <summary>Gets a value indicating whether an item is enabled.</summary>
/// <value><c>true if enabled; otherwise, false.
bool Enabled { get; }
}
/// <summary>
/// A version of <see cref="ComboBox"/> that allows for disabled items.
/// </summary>
[ToolboxBitmap(typeof(Microsoft.Win32.TaskScheduler.TaskEditDialog), "Control")]
public class DisabledItemComboBox : ComboBox
{
private const TextFormatFlags tff = TextFormatFlags.Default | TextFormatFlags.VerticalCenter | TextFormatFlags.SingleLine | TextFormatFlags.NoPadding;
private bool animationsNeedCleanup;
private readonly bool BufferedPaintSupported = false;
private ComboBoxState currentState = ComboBoxState.Normal, newState = ComboBoxState.Normal;
private LBNativeWindow dropDownWindow;
private readonly AnimationTransition<ComboBoxState>[] transitions;
/// <summary>
/// Initializes a new instance of the <see cref="DisabledItemComboBox"/> class.
/// </summary>
public DisabledItemComboBox()
{
SetStyle(/*ControlStyles.Opaque |*/ ControlStyles.UserPaint | ControlStyles.AllPaintingInWmPaint, true);
DrawMode = DrawMode.OwnerDrawFixed;
DropDownStyle = ComboBoxStyle.DropDownList;
if (Environment.OSVersion.Version.Major >= 6 && VisualStyleRenderer.IsSupported && Application.RenderWithVisualStyles)
{
BufferedPaintSupported = true;
var vsr = new VisualStyleRenderer("COMBOBOX", 5, 0);
transitions = new[] {
new AnimationTransition<ComboBoxState>(vsr, ComboBoxState.Normal, ComboBoxState.Hot),
new AnimationTransition<ComboBoxState>(vsr, ComboBoxState.Normal, ComboBoxState.Pressed),
new AnimationTransition<ComboBoxState>(vsr, ComboBoxState.Normal, ComboBoxState.Disabled),
new AnimationTransition<ComboBoxState>(vsr, ComboBoxState.Hot, ComboBoxState.Normal),
new AnimationTransition<ComboBoxState>(vsr, ComboBoxState.Hot, ComboBoxState.Pressed),
new AnimationTransition<ComboBoxState>(vsr, ComboBoxState.Hot, ComboBoxState.Disabled),
new AnimationTransition<ComboBoxState>(vsr, ComboBoxState.Pressed, ComboBoxState.Normal),
new AnimationTransition<ComboBoxState>(vsr, ComboBoxState.Pressed, ComboBoxState.Hot),
new AnimationTransition<ComboBoxState>(vsr, ComboBoxState.Disabled, ComboBoxState.Normal)
};
}
}
/// <summary>
/// Gets or sets a value indicating whether your code or the operating system will handle drawing of elements in the list.
/// </summary>
/// <returns>One of the <see cref="T:System.Windows.Forms.DrawMode" /> enumeration values. The default is .
/// <PermissionSet>
/// <IPermission class="System.Security.Permissions.EnvironmentPermission, mscorlib, Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" version="1" Unrestricted="true" />
/// <IPermission class="System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" version="1" Unrestricted="true" />
/// <IPermission class="System.Security.Permissions.SecurityPermission, mscorlib, Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" version="1" Flags="UnmanagedCode, ControlEvidence" />
/// <IPermission class="System.Diagnostics.PerformanceCounterPermission, System, Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" version="1" Unrestricted="true" />
/// </PermissionSet>
[DefaultValue(DrawMode.OwnerDrawFixed), Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]
public new DrawMode DrawMode
{
get { return base.DrawMode; }
set { base.DrawMode = value; }
}
/// <summary>
/// Gets or sets a value specifying the style of the combo box.
/// </summary>
/// <returns>One of the <see cref="T:System.Windows.Forms.ComboBoxStyle" /> values. The default is DropDown.
/// <PermissionSet>
/// <IPermission class="System.Security.Permissions.EnvironmentPermission, mscorlib, Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" version="1" Unrestricted="true" />
/// <IPermission class="System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" version="1" Unrestricted="true" />
/// <IPermission class="System.Security.Permissions.SecurityPermission, mscorlib, Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" version="1" Flags="UnmanagedCode, ControlEvidence" />
/// <IPermission class="System.Diagnostics.PerformanceCounterPermission, System, Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" version="1" Unrestricted="true" />
/// </PermissionSet>
[DefaultValue(ComboBoxStyle.DropDownList), Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]
public new ComboBoxStyle DropDownStyle
{
get { return base.DropDownStyle; }
set { base.DropDownStyle = value; }
}
/// <summary>
/// Gets or sets the state of the combobox.
/// </summary>
/// <value>
/// The state.
/// </value>
private ComboBoxState State
{
get
{
return currentState;
}
set
{
var diff = !Equals(currentState, value);
newState = value;
if (diff)
{
if (animationsNeedCleanup && IsHandleCreated) NativeMethods.BufferedPaintStopAllAnimations(Handle);
Invalidate();
}
}
}
/// <summary>
/// Determines whether an item is enabled.
/// </summary>
/// <param name="idx">The index of the item.</param>
/// <returns>
/// <c>true</c> if enabled; otherwise, false.
/// </returns>
public bool IsItemEnabled(int idx) => !(idx > -1 && idx < Items.Count && Items[idx] is IEnableable && !((IEnableable)Items[idx]).Enabled);
/// <summary>
/// Releases the unmanaged resources used by the <see cref="T:System.Windows.Forms.ComboBox" /> and optionally releases the managed resources.
/// </summary>
/// <param name="disposing">true to release both managed and unmanaged resources; false to release only unmanaged resources.</param>
protected override void Dispose(bool disposing)
{
if (animationsNeedCleanup)
{
NativeMethods.BufferedPaintUnInit();
animationsNeedCleanup = false;
}
base.Dispose(disposing);
}
/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.ComboBox.DrawItem" /> event.
/// </summary>
/// <param name="e">A <see cref="T:System.Windows.Forms.DrawItemEventArgs" /> that contains the event data.
protected override void OnDrawItem(DrawItemEventArgs e)
{
var itemString = e.Index >= 0 ? GetItemText(Items[e.Index]) : string.Empty;
if ((e.State & DrawItemState.ComboBoxEdit) != DrawItemState.ComboBoxEdit)
{
if (e.Index >= 0)
{
var iEnabled = IsItemEnabled(e.Index);
if (iEnabled)
{
e.DrawBackground();
e.DrawFocusRectangle();
}
else
{
using (var bb = new SolidBrush(e.BackColor))
e.Graphics.FillRectangle(bb, e.Bounds);
}
TextRenderer.DrawText(e.Graphics, itemString, e.Font, Rectangle.Inflate(e.Bounds, -2, 0), iEnabled ? e.ForeColor : SystemColors.GrayText, tff);
}
}
base.OnDrawItem(e);
}
/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.ComboBox.DropDown" /> event.
/// </summary>
/// <param name="e">An <see cref="T:System.EventArgs" /> that contains the event data.
protected override void OnDropDown(EventArgs e)
{
base.OnDropDown(e);
State = ComboBoxState.Pressed;
}
/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.ComboBox.DropDownClosed" /> event.
/// </summary>
/// <param name="e">An <see cref="T:System.EventArgs" /> that contains the event data.
protected override void OnDropDownClosed(EventArgs e)
{
base.OnDropDownClosed(e);
State = ComboBoxState.Normal;
}
/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.Control.HandleCreated" /> event.
/// </summary>
/// <param name="e">An <see cref="T:System.EventArgs" /> that contains the event data.
protected override void OnHandleCreated(EventArgs e)
{
base.OnHandleCreated(e);
if (BufferedPaintSupported)
{
NativeMethods.BufferedPaintInit();
animationsNeedCleanup = true;
}
}
/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.Control.HandleDestroyed" /> event.
/// </summary>
/// <param name="e">An <see cref="T:System.EventArgs" /> that contains the event data.
protected override void OnHandleDestroyed(EventArgs e)
{
dropDownWindow?.DestroyHandle();
base.OnHandleDestroyed(e);
}
/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.Control.KeyPress" /> event.
/// </summary>
/// <param name="e">A <see cref="T:System.Windows.Forms.KeyPressEventArgs" /> that contains the event data.
protected override void OnKeyPress(KeyPressEventArgs e)
{
var idx = FindEnabledString(e.KeyChar.ToString(), SelectedIndex);
if (idx == -1 || idx == SelectedIndex)
e.Handled = true;
base.OnKeyPress(e);
}
/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.Control.LostFocus" /> event.
/// </summary>
/// <param name="e">An <see cref="T:System.EventArgs" /> that contains the event data.
protected override void OnLostFocus(EventArgs e)
{
base.OnLostFocus(e);
Invalidate();
}
/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.Control.MouseDown" /> event.
/// </summary>
/// <param name="e">A <see cref="T:System.Windows.Forms.MouseEventArgs" /> that contains the event data.
protected override void OnMouseDown(MouseEventArgs e)
{
base.OnMouseDown(e);
State = ComboBoxState.Pressed;
}
/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.Control.MouseEnter" /> event.
/// </summary>
/// <param name="e">An <see cref="T:System.EventArgs" /> that contains the event data.
protected override void OnMouseEnter(EventArgs e)
{
base.OnMouseEnter(e);
State = ComboBoxState.Hot;
}
/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.Control.MouseLeave" /> event.
/// </summary>
/// <param name="e">An <see cref="T:System.EventArgs" /> that contains the event data.
protected override void OnMouseLeave(EventArgs e)
{
base.OnMouseLeave(e);
if (State != ComboBoxState.Pressed)
State = ComboBoxState.Normal;
}
/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.Control.MouseMove" /> event.
/// </summary>
/// <param name="e">A <see cref="T:System.Windows.Forms.MouseEventArgs" /> that contains the event data.
protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove(e);
if (State != ComboBoxState.Pressed)
State = ComboBoxState.Hot;
}
/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.Control.Paint" /> event.
/// </summary>
/// <param name="e">A <see cref="T:System.Windows.Forms.PaintEventArgs" /> that contains the event data.
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
if (BufferedPaintSupported)
{
var stateChanged = !Equals(currentState, newState);
using (var hdc = new SafeGDIHandle(e.Graphics))
{
if (hdc.IsInvalid || NativeMethods.BufferedPaintRenderAnimation(Handle, hdc)) return;
var animParams = new NativeMethods.BufferedPaintAnimationParams(NativeMethods.BufferedPaintAnimationStyle.Linear);
// get appropriate animation time depending on state transition (or 0 if unchanged)
if (stateChanged)
{
foreach (var item in transitions)
if (item.currentState == currentState && item.newState == newState)
{
animParams.Duration = item.duration;
break;
}
}
var rc = ClientRectangle;
IntPtr hdcFrom, hdcTo;
var hbpAnimation = NativeMethods.BeginBufferedAnimation(Handle, hdc, ref rc, NativeMethods.BufferedPaintBufferFormat.CompatibleBitmap, IntPtr.Zero, ref animParams, out hdcFrom, out hdcTo);
if (hbpAnimation != IntPtr.Zero)
{
if (hdcFrom != IntPtr.Zero)
{
using (var gfxFrom = Graphics.FromHdc(hdcFrom))
PaintControl(new PaintEventArgs(gfxFrom, e.ClipRectangle));
}
currentState = newState;
if (hdcTo != IntPtr.Zero)
{
using (var gfxTo = Graphics.FromHdc(hdcTo))
PaintControl(new PaintEventArgs(gfxTo, e.ClipRectangle));
}
NativeMethods.EndBufferedAnimation(hbpAnimation, true);
}
else
{
hdc.Dispose();
currentState = newState;
PaintControl(e);
}
}
}
else
{
// buffered painting not supported, just paint using the current state
currentState = newState;
PaintControl(e);
}
}
/// <summary>
/// Paints the background of the control.
/// </summary>
/// <param name="pevent">A <see cref="T:System.Windows.Forms.PaintEventArgs" /> that contains information about the control to paint.
protected override void OnPaintBackground(PaintEventArgs pevent)
{
// don't paint the control's background
}
/// <summary>
/// Paints the control.
/// </summary>
/// <param name="e">The <see cref="PaintEventArgs"/> instance containing the event data.
protected virtual void PaintControl(PaintEventArgs e)
{
var cbi = NativeMethods.COMBOBOXINFO.FromComboBox(this);
var itemText = SelectedIndex >= 0 ? GetItemText(SelectedItem) : string.Empty;
var state = Enabled ? currentState : ComboBoxState.Disabled;
Rectangle tr = cbi.rcItem;
/*Rectangle tr = this.ClientRectangle;
tr.Width -= (SystemInformation.VerticalScrollBarWidth + 2);
tr.Inflate(0, -2);
tr.Offset(1, 0);*/
Rectangle br = cbi.rcButton;
var vsSuccess = false;
if (VisualStyleRenderer.IsSupported && Application.RenderWithVisualStyles)
{
/*Rectangle r = Rectangle.Inflate(this.ClientRectangle, 1, 1);
if (this.DropDownStyle != ComboBoxStyle.DropDownList)
{
e.Graphics.Clear(this.BackColor);
ComboBoxRenderer.DrawTextBox(e.Graphics, r, itemText, this.Font, tr, tff, state);
ComboBoxRenderer.DrawDropDownButton(e.Graphics, br, state);
}
else*/
{
try
{
var vr = new VisualStyleRenderer("Combobox", DropDownStyle == ComboBoxStyle.DropDownList ? 5 : 4, (int)state);
vr.DrawParentBackground(e.Graphics, ClientRectangle, this);
vr.DrawBackground(e.Graphics, ClientRectangle);
if (DropDownStyle != ComboBoxStyle.DropDownList) br.Inflate(1, 1);
var cr = DropDownStyle == ComboBoxStyle.DropDownList ? Rectangle.Inflate(br, -1, -1) : br;
vr.SetParameters("Combobox", 7, (int)(br.Contains(PointToClient(Cursor.Position)) ? state : ComboBoxState.Normal));
vr.DrawBackground(e.Graphics, br, cr);
if (Focused && State != ComboBoxState.Pressed)
{
var sz = TextRenderer.MeasureText(e.Graphics, "Wg", Font, tr.Size, TextFormatFlags.Default);
var fr = Rectangle.Inflate(tr, 0, (sz.Height - tr.Height) / 2 + 1);
ControlPaint.DrawFocusRectangle(e.Graphics, fr);
}
var fgc = Enabled ? ForeColor : SystemColors.GrayText;
TextRenderer.DrawText(e.Graphics, itemText, Font, tr, fgc, tff);
vsSuccess = true;
}
catch { }
}
}
if (!vsSuccess)
{
Diagnostics.Debug.WriteLine($"CR:{ClientRectangle};ClR:{e.ClipRectangle};Foc:{Focused};St:{state};Tx:{itemText}");
var focusedNotPressed = Focused && state != ComboBoxState.Pressed;
var bgc = Enabled ? (focusedNotPressed ? SystemColors.Highlight : BackColor) : SystemColors.Control;
var fgc = Enabled ? (focusedNotPressed ? SystemColors.HighlightText : ForeColor) : SystemColors.GrayText;
e.Graphics.Clear(bgc);
ControlPaint.DrawBorder3D(e.Graphics, ClientRectangle, Border3DStyle.Sunken);
ControlPaint.DrawComboButton(e.Graphics, br, Enabled ? (state == ComboBoxState.Pressed ? ButtonState.Pushed : ButtonState.Normal) : ButtonState.Inactive);
tr = new Rectangle(tr.X + 3, tr.Y + 1, tr.Width - 4, tr.Height - 2);
TextRenderer.DrawText(e.Graphics, itemText, Font, tr, fgc, tff);
if (focusedNotPressed)
{
var fr = Rectangle.Inflate(cbi.rcItem, -1, -1);
fr.Height++;
fr.Width++;
ControlPaint.DrawFocusRectangle(e.Graphics, fr, fgc, bgc);
e.Graphics.DrawRectangle(SystemPens.Window, cbi.rcItem);
}
}
}
/// <summary>
/// Processes a command key.
/// </summary>
/// <param name="msg">A <see cref="T:System.Windows.Forms.Message" />, passed by reference, that represents the window message to process.
/// <param name="keyData">One of the <see cref="T:System.Windows.Forms.Keys" /> values that represents the key to process.
/// <returns>
/// true if the character was processed by the control; otherwise, false.
/// </returns>
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
var visItems = DropDownHeight / ItemHeight;
switch (keyData)
{
case Keys.Down:
case Keys.Right:
SelectedIndex = GetNextEnabledItemIndex(SelectedIndex, true);
return true;
case Keys.Up:
case Keys.Left:
SelectedIndex = GetNextEnabledItemIndex(SelectedIndex, false);
return true;
case Keys.PageDown:
if (SelectedIndex + visItems > Items.Count)
SelectedIndex = GetNextEnabledItemIndex(Items.Count, false);
else
SelectedIndex = GetNextEnabledItemIndex(SelectedIndex + visItems, true);
return true;
case Keys.PageUp:
if (SelectedIndex - visItems < 0)
SelectedIndex = GetNextEnabledItemIndex(-1, true);
else
SelectedIndex = GetNextEnabledItemIndex(SelectedIndex - visItems, false);
return true;
case Keys.Home:
SelectedIndex = GetNextEnabledItemIndex(-1, true);
return true;
case Keys.End:
SelectedIndex = GetNextEnabledItemIndex(Items.Count, false);
return true;
case Keys.Enter:
var pt = dropDownWindow.MapPointToClient(Cursor.Position);
var idx = dropDownWindow.IndexFromPoint(pt.X, pt.Y);
if (idx >= 0 && IsItemEnabled(idx))
return false;
DroppedDown = false;
return true;
case Keys.Escape:
DroppedDown = false;
return true;
}
return base.ProcessCmdKey(ref msg, keyData);
}
/// <summary>
/// Processes Windows messages.
/// </summary>
/// <param name="m">The Windows <see cref="T:System.Windows.Forms.Message" /> to process.
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
if ((int)(long)m.WParam == 0x3e80001)
{
dropDownWindow = new LBNativeWindow(m.LParam, this);
}
}
private int FindEnabledString(string str, int startIndex)
{
if (str != null)
{
if (startIndex < -1 || startIndex >= Items.Count)
return -1;
var length = str.Length;
var num2 = 0;
for (var i = (startIndex + 1) % Items.Count; num2 < Items.Count; i = (i + 1) % Items.Count)
{
num2++;
if (IsItemEnabled(i) && string.Compare(str, 0, GetItemText(Items[i]), 0, length, true, Globalization.CultureInfo.CurrentUICulture) == 0)
return i;
}
}
return -1;
}
private int GetNextEnabledItemIndex(int startIndex, bool forward = true)
{
if (forward)
{
for (var i = startIndex + 1; i < Items.Count; i++)
{
if (IsItemEnabled(i))
return i;
}
return startIndex;
}
else
{
for (var i = startIndex - 1; i >= 0; i--)
{
if (IsItemEnabled(i))
return i;
}
return startIndex;
}
}
private struct AnimationTransition<T>
{
public readonly T currentState;
public readonly uint duration;
public readonly T newState;
public AnimationTransition(VisualStyleRenderer rnd, T fromState, T toState)
{
if (rnd.State != Convert.ToInt32(fromState))
rnd.SetParameters(rnd.Class, rnd.Part, Convert.ToInt32(fromState));
currentState = fromState;
newState = toState;
duration = rnd.GetTransitionDuration(Convert.ToInt32(toState));
}
}
private class LBNativeWindow : NativeWindow
{
private readonly DisabledItemComboBox Parent;
public LBNativeWindow(IntPtr handle, DisabledItemComboBox parent)
{
Parent = parent;
AssignHandle(handle);
}
public int IndexFromPoint(int x, int y)
{
var n = NativeMethods.SendMessage(Handle, 0x1a9 /* LB_ITEMFROMPOINT */, IntPtr.Zero, NativeMethods.Util.MAKELPARAM(x, y)).ToInt32();
if (NativeMethods.Util.HIWORD(n) == 0)
return NativeMethods.Util.LOWORD(n);
return -1;
}
protected override void WndProc(ref Message m)
{
if (m.Msg == 0x0202 || m.Msg == 0x0201 || m.Msg == 0x0203) /* WM_LBUTTONUP or WM_LBUTTONDOWN or WM_LBUTTONDBLCLK */
{
var idx = IndexFromPoint(NativeMethods.Util.SignedLOWORD(m.LParam), NativeMethods.Util.SignedHIWORD(m.LParam));
if (idx >= 0 && !Parent.IsItemEnabled(idx))
return;
}
base.WndProc(ref m);
}
}
}
}
