我正在开发一个自定义的组合框控件，它由标准的组合框架组成，根据这里的文章看起来平坦无边框：
http://www.codeproject.com/Articles/6971/Making-Standard-ComboBox-appear-flat
根据各种来源，我将不得不重写Windows程序，所以这里是我的WndProc覆盖，我阻止了几个消息到达控件：
protected override void WndProc(ref Message m)
{
IntPtr hDC = IntPtr.Zero;
Graphics gdc = null;
switch (m.Msg)
{
// Block these messages
case WM_CHANGEUISTATE:
case WM_MOUSEACTIVATE:
case WM_MOUSEFIRST:
case WM_MOUSELAST:
case WM_MOUSEHOVER:
case WM_MOUSELEAVE:
m.Result = (IntPtr)1;
break;
// Here we paint the border when non-client paint is received
case WM_NC_PAINT:
hDC = GetWindowDC(this.Handle);
gdc = Graphics.FromHdc(hDC);
SendMessage(this.Handle, WM_ERASEBKGND, hDC, 0);
SendPrintClientMsg(); // Send to draw client area
PaintFlatControlBorder(this, gdc);
m.Result = (IntPtr) 1; // Indicate message has been processed
ReleaseDC(m.HWnd, hDC);
gdc.Dispose();
break;
case WM_PAINT:
base.WndProc(ref m);
// Flatten the border area again
hDC = GetWindowDC(this.Handle);
gdc = Graphics.FromHdc(hDC);
Pen p = new Pen((this.Enabled? BackColor:SystemColors.Control), 2);
gdc.DrawRectangle(p, new Rectangle(2, 2, this.Width-3, this.Height-3));
PaintFlatDropDown(this, gdc);
PaintFlatControlBorder(this, gdc);
ReleaseDC(m.HWnd, hDC);
gdc.Dispose();
break;
default:
base.WndProc(ref m);
break;
}
}
这是我的构造函数：
public FlatComboBox() : base()
{
this.FlatStyle = FlatStyle.Flat;
this.SetStyle(ControlStyles.DoubleBuffer | ControlStyles.ResizeRedraw, true);
}
我还需要阻止哪些其他wndproc消息，还是有另外一种解决方法？
以下是所有wndproc消息的良好参考：
https://www.autoitscript.com/autoit3/docs/appendix/WinMsgCodes.htm
我正在使用.NET v4.5。
提前致谢。
答案 0 :(得分：1)
我之前使用组合框为它提供了一个可自定义的平面外观，我显示完整的代码，以便更容易了解它的工作原理，但它使用自定义下拉菜单和菜单项完成外观。
using System;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;
namespace Custom.Controls
{
public class CustomComboBox : UserControl
{
private const int DEFAULT_WIDTH = 121;
private const int DEFAULT_HEIGHT = 20;
private CustomContextMenuStrip _popupControl;
private CustomToolStripMenuItem _selectedItem;
private bool _bDroppedDown;
private Color _borderColour;
private Color _dropDownButtonColour;
private Color _droppedDownArrowColour;
private Color _closedArrowColour;
private Color _dropDownBackColour;
private Color _dropDownForeColour;
private Color _dropDownBorderColour;
public Color BorderColour
{
get
{
return _borderColour;
}
set
{
_borderColour = value;
this.Invalidate();
}
}
public Color ClosedArrowColour
{
get
{
return _closedArrowColour;
}
set
{
_closedArrowColour = value;
this.Invalidate();
}
}
public Color DroppedDownArrowColour
{
get
{
return _droppedDownArrowColour;
}
set
{
_droppedDownArrowColour = value;
this.Invalidate();
}
}
public Color DropDownButtonColour
{
get
{
return _dropDownButtonColour;
}
set
{
_dropDownButtonColour = value;
this.Invalidate();
}
}
public Color DropDownBorderColour
{
get
{
return _dropDownBorderColour;
}
set
{
_dropDownBorderColour = value;
_popupControl.BorderColour = value;
this.Invalidate();
}
}
public Color DropDownBackColour
{
get
{
return _dropDownBackColour;
}
set
{
_dropDownBackColour = value;
_popupControl.BackColor = value;
this.Invalidate();
}
}
public Color DropDownForeColour
{
get
{
return _dropDownForeColour;
}
set
{
_dropDownForeColour = value;
_popupControl.ForeColor = value;
this.Invalidate();
}
}
public bool DropShadowEnabled
{
get
{
return _popupControl.DropShadowEnabled;
}
set
{
_popupControl.DropShadowEnabled = value;
this.Invalidate();
}
}
public bool DroppedDown
{
get
{
return _bDroppedDown;
}
set
{
_bDroppedDown = value;
if (value)
{
_popupControl.Show(this, new Point(0, this.Height), ToolStripDropDownDirection.BelowRight);
}
else
{
_popupControl.Hide();
}
this.Invalidate();
}
}
public ToolStripItemCollection Items
{
get
{
return _popupControl.Items;
}
}
public CustomToolStripMenuItem SelectedItem
{
get
{
return _selectedItem;
}
}
public CustomComboBox()
{
this.SetStyle(ControlStyles.ResizeRedraw, true);
this.SetStyle(ControlStyles.Selectable, true);
this.SetStyle(ControlStyles.UserMouse, true);
this.SetStyle(ControlStyles.UserPaint, true);
this.SuspendLayout();
this.ResumeLayout(false);
_popupControl = new CustomContextMenuStrip();
_popupControl.BackColor = this.BackColor;
_popupControl.Closed += new ToolStripDropDownClosedEventHandler(PopupControl_Closed);
_popupControl.ItemClicked += new ToolStripItemClickedEventHandler(PopupControl_ItemClicked);
this.Width = DEFAULT_WIDTH;
this.Height = DEFAULT_HEIGHT;
_selectedItem = null;
_bDroppedDown = false;
this.BackColor = SystemColors.Control;
this.ForeColor = SystemColors.ControlText;
_borderColour = SystemColors.ActiveBorder;
_dropDownButtonColour = SystemColors.ButtonFace;
_droppedDownArrowColour = SystemColors.ControlLight;
_closedArrowColour = SystemColors.ControlDark;
//Set these via the properties so they take effect on _popupControl
this.DropDownBackColour = SystemColors.Control;
this.DropDownForeColour = SystemColors.ControlText;
this.DropDownBorderColour = SystemColors.ActiveBorder;
}
protected override void OnFontChanged(EventArgs e)
{
_popupControl.Font = this.Font;
base.OnFontChanged(e);
}
protected override void OnMouseDown(MouseEventArgs e)
{
this.Invalidate();
this.DroppedDown = !this.DroppedDown;
base.OnMouseDown(e);
}
protected override void OnMouseWheel(MouseEventArgs e)
{
int nIndex = this.Items.IndexOf(_selectedItem);
if (e.Delta < 0)
{
if (nIndex < (this.Items.Count - 1))
{
_selectedItem = (CustomToolStripMenuItem)this.Items[nIndex + 1];
OnSelectedItemChanged(EventArgs.Empty);
this.Invalidate();
}
}
else if (e.Delta > 0)
{
if (nIndex > 0)
{
_selectedItem = (CustomToolStripMenuItem)this.Items[nIndex - 1];
OnSelectedItemChanged(EventArgs.Empty);
this.Invalidate();
}
}
base.OnMouseWheel(e);
}
protected override void OnPaint(PaintEventArgs e)
{
Rectangle boundingRect = new Rectangle(0, 0, this.Width, this.Height);
using (SolidBrush brush = new SolidBrush(this.BackColor))
{
e.Graphics.FillRectangle(brush, boundingRect);
}
ControlPaint.DrawBorder(e.Graphics, boundingRect, _borderColour, ButtonBorderStyle.Solid);
//Draw the dropdown button background
int nButtonWidth = SystemInformation.VerticalScrollBarWidth + SystemInformation.VerticalFocusThickness;
Rectangle dropDownButtonRect = new Rectangle(this.Width - nButtonWidth, 0, nButtonWidth, this.Height);
using (SolidBrush brush = new SolidBrush(_dropDownButtonColour))
{
e.Graphics.FillRectangle(brush, dropDownButtonRect);
}
//Draw the dropdown button arrow
using (GraphicsPath path = new GraphicsPath())
{
Point pTopLeft = new Point()
{
X = (int)Math.Round((float)dropDownButtonRect.X + ((float)dropDownButtonRect.Width * 0.30f)),
Y = (int)Math.Round((float)dropDownButtonRect.Y + ((float)dropDownButtonRect.Height * 0.35f))
};
Point pTopRight = new Point()
{
X = (int)Math.Round((float)dropDownButtonRect.X + ((float)dropDownButtonRect.Width * 0.70f)),
Y = (int)Math.Round((float)dropDownButtonRect.Y + ((float)dropDownButtonRect.Height * 0.35f))
};
Point pBottom = new Point()
{
X = (int)Math.Round((float)dropDownButtonRect.X + ((float)dropDownButtonRect.Width * 0.5f)),
Y = (int)Math.Round((float)dropDownButtonRect.Y + ((float)dropDownButtonRect.Height * 0.65f))
};
path.AddLine(pTopLeft, pTopRight);
path.AddLine(pTopRight, pBottom);
SmoothingMode previousSmoothingMode = e.Graphics.SmoothingMode;
e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
{
using (SolidBrush brush = new SolidBrush(_bDroppedDown ? _droppedDownArrowColour : _closedArrowColour))
{
e.Graphics.FillPath(brush, path);
}
}
e.Graphics.SmoothingMode = previousSmoothingMode;
}
if (_selectedItem != null)
{
using (SolidBrush brush = new SolidBrush(this.ForeColor))
{
SizeF stringSize = e.Graphics.MeasureString(_selectedItem.Text, this.Font);
e.Graphics.DrawString(_selectedItem.Text, this.Font, brush, new Point(0, (this.Height / 2) - ((int)stringSize.Height / 2)));
}
}
}
protected override void OnSizeChanged(EventArgs e)
{
if (_popupControl != null)
{
_popupControl.MaximumItemSize = new Size(this.Width - 1, _popupControl.MaximumItemSize.Height);
_popupControl.Width = this.Width;
}
base.OnSizeChanged(e);
}
private void OnSelectedItemChanged(EventArgs e)
{
if (SelectedItemChanged != null)
{
SelectedItemChanged(this, e);
}
}
public void SelectFirstItem()
{
if (this.Items != null && this.Items.Count > 0)
{
_selectedItem = (CustomToolStripMenuItem)this.Items[0];
OnSelectedItemChanged(EventArgs.Empty);
}
}
public event EventHandler SelectedItemChanged;
private void PopupControl_Closed(object sender, ToolStripDropDownClosedEventArgs e)
{
this.DroppedDown = false;
this.Invalidate(true);
}
private void PopupControl_ItemClicked(object sender, ToolStripItemClickedEventArgs e)
{
_selectedItem = (CustomToolStripMenuItem)e.ClickedItem;
OnSelectedItemChanged(EventArgs.Empty);
}
}
}