在面板内控件顶部绘制（C#WinForms）
我知道这个问题已经被问了好几次了，但到目前为止我还没有找到一个好的解决办法 我有一个面板，上面有其他控件。在面板内控件顶部绘制（C#WinForms）,c#,.net,winforms,C#,.net,Winforms,我知道这个问题已经被问了好几次了，但到目前为止我还没有找到一个好的解决办法 我有一个面板，上面有其他控件。 我想在它和面板中所有控件的顶部画一条线 我遇到了3种类型的解决方案（其中没有一种是按照我想要的方式工作的）： 获取桌面DC并在屏幕上绘制。 如果其他应用程序与表单重叠，这将利用它们 覆盖面板的“CreateParams”： = //注意，我还尝试禁用WS_剪辑 然后在Paint（）上绘制线条。 但是由于在面板中控件的OnPaint之前调用面板的OnPaint， 内部控件的绘图仅在线条顶部绘
我想在它和面板中所有控件的顶部画一条线 我遇到了3种类型的解决方案（其中没有一种是按照我想要的方式工作的）：
如果其他应用程序与表单重叠，这将利用它们
我看到有人建议使用消息过滤器来收听WM_PAINT mesages，并使用计时器，但我认为这种解决方案既不是“良好做法”，也不是有效的。
你会怎么做？确定内部控件在X ms后已完成绘图，并将计时器设置为X ms
此屏幕截图显示关闭了WS_ClipSpilings和WS_CLIPCHILDREN的面板。
蓝色线绘制在面板的OnPaint上，仅由文本框和标签绘制。
红线绘制在顶部只是因为它不是从面板的OnPaint绘制的（它实际上是通过单击按钮绘制的）
第三：创建一个透明层并在该层顶部绘制。
我使用以下方法创建了一个透明控件：
protected override CreateParams CreateParams {
get {
CreateParams cp = base.CreateParams;
cp.ExStyle |= 0x00000020; //WS_EX_TRANSPARENT
return cp;
}
}
我曾尝试使用“BringToFront（）”将其放在前面，但似乎没有任何帮助。
我已将其放入行控件的OnPaint（）处理程序中。
我应该试着把它放在别的地方吗？？
-这也会造成面板顶部有另一个控件的问题。（捕捉鼠标点击等） 任何帮助都将不胜感激 **编辑： 黑线是我试图做的一个例子。（已使用windows paint进行绘制）
如果您希望线条只是一条简单的水平线或垂直线，请在主面板上放置另一个面板（禁用以使其不会拾取任何鼠标事件），将其高度（或宽度）设置为3或4像素（或任何您想要的），然后将其置于前面。如果需要在运行时更改线的位置，只需移动面板，使其可见和不可见即可。下面是它的外观：
你甚至可以点击任何你喜欢的地方，而且这些线一点也不干涉。这条线是在任何类型的控件上绘制的（尽管组合框或日期选择器的下拉部分仍然显示在这条线的上方，这是很好的）。蓝线是相同的东西，但会被发送到后面。我能想到的唯一简单的解决方案是为每个要在上面绘制的控件创建绘制事件处理程序。然后在这些处理程序之间协调线条绘制。这不是最方便的解决方案，但是这将使您能够在控件顶部绘制 假设按钮是面板的子控件：
panel.Paint += new PaintEventHandler(panel_Paint);
button.Paint += new PaintEventHandler(button_Paint);
protected void panel_Paint(object sender, PaintEventArgs e)
{
//draw the full line which will then be partially obscured by child controls
}
protected void button_Paint(object sender, PaintEventArgs e)
{
//draw the obscured line portions on the button
}
windows窗体面板是控件的容器。如果要在面板中其他控件的顶部绘制某些内容，则需要另一个控件（位于z顺序的顶部） 幸运的是，您可以创建具有非矩形边框的windows窗体控件。看看这个技巧： 要仅在屏幕上绘制某些内容，请使用标签控件，然后关闭“自动调整大小”。然后附加到绘制事件并设置大小和区域属性 下面是一个代码示例：
private void label1_Paint(object sender, PaintEventArgs e)
{
System.Drawing.Drawing2D.GraphicsPath myGraphicsPath = new System.Drawing.Drawing2D.GraphicsPath();
myGraphicsPath.AddEllipse(new Rectangle(0, 0, 125, 125));
myGraphicsPath.AddEllipse(new Rectangle(75, 75, 20, 20));
myGraphicsPath.AddEllipse(new Rectangle(120, 0, 125, 125));
myGraphicsPath.AddEllipse(new Rectangle(145, 75, 20, 20));
//Change the button's background color so that it is easy
//to see.
label1.BackColor = Color.ForestGreen;
label1.Size = new System.Drawing.Size(256, 256);
label1.Region = new Region(myGraphicsPath);
}
我认为最好的方法是继承你想要划定界限的控制权。重写OnPaint方法，从内部调用base.Paint（），然后使用相同的图形实例绘制线。同时，您还可以拥有一个参数，该参数指定在哪一点绘制直线，以便您可以直接从主窗体控制直线 原始代码应为：
protected override CreateParams CreateParams
{
get
{
CreateParams cp;
cp = base.CreateParams;
cp.Style &= 0x7DFFFFFF; //WS_CLIPCHILDREN
return cp;
}
}
这个有用 是的，这是可以做到的。问题在于，面板及其上的控件都是单独的窗口（在API意义上），因此都是单独的图形表面。没有一个绘图面可以绘制以获得这种效果（除了顶层屏幕表面，在上面绘制是不礼貌的） （cough-hack-cough）技巧是在控件下面的面板上画线，同时在每个控件本身上画线，从而产生这种效果（即使单击按钮并移动鼠标，这种效果也会持续）： 创建winforms项目（默认情况下，该项目应随Form1一起提供）。如图所示，在面板上添加一个面板（名为“panel1”）和两个按钮（“button1”和“button2”）。在窗体的构造函数中添加以下代码：
panel1.Paint += PaintPanelOrButton;
button1.Paint += PaintPanelOrButton;
button2.Paint += PaintPanelOrButton;
private void PaintPanelOrButton(object sender, PaintEventArgs e)
{
// center the line endpoints on each button
Point pt1 = new Point(button1.Left + (button1.Width / 2),
button1.Top + (button1.Height / 2));
Point pt2 = new Point(button2.Left + (button2.Width / 2),
button2.Top + (button2.Height / 2));
if (sender is Button)
{
// offset line so it's drawn over the button where
// the line on the panel is drawn
Button btn = (Button)sender;
pt1.X -= btn.Left;
pt1.Y -= btn.Top;
pt2.X -= btn.Left;
pt2.Y -= btn.Top;
}
e.Graphics.DrawLine(new Pen(Color.Red, 4.0F), pt1, pt2);
}
private void PaintPanelOrButton(object sender, PaintEventArgs e)
{
// center the line endpoints on each button
Point pt1 = new Point(button1.Left + (button1.Width / 2),
button1.Top + (button1.Height / 2));
Point pt2 = new Point(button2.Left + (button2.Width / 2),
button2.Top + (button2.Height / 2));
if (sender is Button)
{
// offset line so it's drawn over the button where
// the line on the panel is drawn
Button btn = (Button)sender;
pt1.X -= btn.Left;
pt1.Y -= btn.Top;
pt2.X -= btn.Left;
pt2.Y -= btn.Top;
}
e.Graphics.DrawLine(new Pen(Color.Red, 4.0F), pt1, pt2);
}
public partial class MainForm : Form
{
public MainForm()
{
InitializeComponent();
this.simpleLine1.BringToFront();
}
}
using System;
using System.Windows.Forms;
using System.Drawing;
using System.Collections.Generic;
public class SimpleLine : Control
{
private Control parentHooked;
private List<Control> controlsHooked;
public enum LineType
{
Horizontal,
Vertical,
ForwardsDiagonal,
BackwardsDiagonal
}
public event EventHandler AppearanceChanged;
private LineType appearance;
public virtual LineType Appearance
{
get
{
return appearance;
}
set
{
if (appearance != value)
{
this.SuspendLayout();
switch (appearance)
{
case LineType.Horizontal:
if (value == LineType.Vertical)
{
this.Height = this.Width;
}
break;
case LineType.Vertical:
if (value == LineType.Horizontal)
{
this.Width = this.Height;
}
break;
}
this.ResumeLayout(false);
appearance = value;
this.PerformLayout();
this.Invalidate();
}
}
}
protected virtual void OnAppearanceChanged(EventArgs e)
{
if (AppearanceChanged != null) AppearanceChanged(this, e);
}
public event EventHandler LineColorChanged;
private Color lineColor;
public virtual Color LineColor
{
get
{
return lineColor;
}
set
{
if (lineColor != value)
{
lineColor = value;
this.Invalidate();
}
}
}
protected virtual void OnLineColorChanged(EventArgs e)
{
if (LineColorChanged != null) LineColorChanged(this, e);
}
public event EventHandler LineWidthChanged;
private float lineWidth;
public virtual float LineWidth
{
get
{
return lineWidth;
}
set
{
if (lineWidth != value)
{
if (0 >= value)
{
lineWidth = 1;
}
lineWidth = value;
this.PerformLayout();
}
}
}
protected virtual void OnLineWidthChanged(EventArgs e)
{
if (LineWidthChanged != null) LineWidthChanged(this, e);
}
public SimpleLine()
{
base.SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.Selectable, false);
base.SetStyle(ControlStyles.SupportsTransparentBackColor, true);
base.BackColor = Color.Transparent;
InitializeComponent();
appearance = LineType.Vertical;
LineColor = Color.Black;
LineWidth = 1;
controlsHooked = new List<Control>();
this.ParentChanged += new EventHandler(OnSimpleLineParentChanged);
}
private void RemoveControl(Control control)
{
if (controlsHooked.Contains(control))
{
control.Paint -= new PaintEventHandler(OnControlPaint);
if (control is TextboxX)
{
TextboxX text = (TextboxX)control;
text.DoingAPaint -= new EventHandler(text_DoingAPaint);
}
controlsHooked.Remove(control);
}
}
void text_DoingAPaint(object sender, EventArgs e)
{
this.Invalidate();
}
private void AddControl(Control control)
{
if (!controlsHooked.Contains(control))
{
control.Paint += new PaintEventHandler(OnControlPaint);
if (control is TextboxX)
{
TextboxX text = (TextboxX)control;
text.DoingAPaint += new EventHandler(text_DoingAPaint);
}
controlsHooked.Add(control);
}
}
private void OnSimpleLineParentChanged(object sender, EventArgs e)
{
UnhookParent();
if (Parent != null)
{
foreach (Control c in Parent.Controls)
{
AddControl(c);
}
Parent.ControlAdded += new ControlEventHandler(OnParentControlAdded);
Parent.ControlRemoved += new ControlEventHandler(OnParentControlRemoved);
parentHooked = this.Parent;
}
}
private void UnhookParent()
{
if (parentHooked != null)
{
foreach (Control c in parentHooked.Controls)
{
RemoveControl(c);
}
parentHooked.ControlAdded -= new ControlEventHandler(OnParentControlAdded);
parentHooked.ControlRemoved -= new ControlEventHandler(OnParentControlRemoved);
parentHooked = null;
}
}
private void OnParentControlRemoved(object sender, ControlEventArgs e)
{
RemoveControl(e.Control);
}
private void OnControlPaint(object sender, PaintEventArgs e)
{
int indexa =Parent.Controls.IndexOf(this) , indexb = Parent.Controls.IndexOf((Control)sender);
//if above invalidate on paint
if(indexa < indexb)
{
Invalidate();
}
}
private void OnParentControlAdded(object sender, ControlEventArgs e)
{
AddControl(e.Control);
}
private System.ComponentModel.IContainer components = null;
private void InitializeComponent()
{
components = new System.ComponentModel.Container();
}
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}
protected override CreateParams CreateParams
{
get
{
CreateParams cp = base.CreateParams;
cp.ExStyle |= 0x20; // Turn on WS_EX_TRANSPARENT
return cp;
}
}
protected override void OnLayout(LayoutEventArgs levent)
{
switch (this.Appearance)
{
case LineType.Horizontal:
this.Height = (int)LineWidth;
this.Invalidate();
break;
case LineType.Vertical:
this.Width = (int)LineWidth;
this.Invalidate();
break;
}
base.OnLayout(levent);
}
protected override void OnPaintBackground(PaintEventArgs pevent)
{
//disable background paint
}
protected override void OnPaint(PaintEventArgs pe)
{
switch (Appearance)
{
case LineType.Horizontal:
DrawHorizontalLine(pe);
break;
case LineType.Vertical:
DrawVerticalLine(pe);
break;
case LineType.ForwardsDiagonal:
DrawFDiagonalLine(pe);
break;
case LineType.BackwardsDiagonal:
DrawBDiagonalLine(pe);
break;
}
}
private void DrawFDiagonalLine(PaintEventArgs pe)
{
using (Pen p = new Pen(this.LineColor, this.LineWidth))
{
pe.Graphics.DrawLine(p, this.ClientRectangle.X, this.ClientRectangle.Bottom,
this.ClientRectangle.Right, this.ClientRectangle.Y);
}
}
private void DrawBDiagonalLine(PaintEventArgs pe)
{
using (Pen p = new Pen(this.LineColor, this.LineWidth))
{
pe.Graphics.DrawLine(p, this.ClientRectangle.X, this.ClientRectangle.Y,
this.ClientRectangle.Right, this.ClientRectangle.Bottom);
}
}
private void DrawHorizontalLine(PaintEventArgs pe)
{
int y = this.ClientRectangle.Height / 2;
using (Pen p = new Pen(this.LineColor, this.LineWidth))
{
pe.Graphics.DrawLine(p, this.ClientRectangle.X, y,
this.ClientRectangle.Width, y);
}
}
private void DrawVerticalLine(PaintEventArgs pe)
{
int x = this.ClientRectangle.Width / 2;
using (Pen p = new Pen(this.LineColor, this.LineWidth))
{
pe.Graphics.DrawLine(p,x, this.ClientRectangle.Y,
x, this.ClientRectangle.Height);
}
}
}
public class TextboxX : TextBox
{
public event EventHandler DoingAPaint;
protected override void WndProc(ref Message m)
{
switch ((int)m.Msg)
{
case (int)NativeMethods.WindowMessages.WM_PAINT:
case (int)NativeMethods.WindowMessages.WM_ERASEBKGND:
case (int)NativeMethods.WindowMessages.WM_NCPAINT:
case 8465: //not sure what this is WM_COMMAND?
if(DoingAPaint!=null)DoingAPaint(this,EventArgs.Empty);
break;
}
base.WndProc(ref m);
}
}
using System.Drawing.Drawing2D;
int wfactor = 4; // half the line width, kinda
// create 6 points for path
Point[] pts = {
new Point(0, 0),
new Point(wfactor, 0),
new Point(Width, Height - wfactor),
new Point(Width, Height) ,
new Point(Width - wfactor, Height),
new Point(0, wfactor) };
// magic numbers!
byte[] types = {
0, // start point
1, // line
1, // line
1, // line
1, // line
1 }; // line
GraphicsPath path = new GraphicsPath(pts, types);
this.Region = new Region(path);
this.Region=new Region(new System.Drawing.Drawing2D.GraphicsPath(new Point[]{new Point(0,0),new Point(4,0),new Point(Width,Height-4),new Point(Width,Height),new Point(Width-4,Height),new Point(0,4)},new byte[]{0,1,1,1,1,1}));
using System;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Drawing;
using System.Windows.Forms;
using System.Windows.Forms.Design;
namespace WindowsFormsApplication3
{
[Designer("WindowsFormsApplication3.DecoratedPanelDesigner")]
public class DecoratedPanel : Panel
{
#region decorationcanvas
// this is an internal transparent panel.
// This is our canvas we'll draw the lines on ...
private class DecorationCanvas : Panel
{
public DecorationCanvas()
{
// don't paint the background
SetStyle(ControlStyles.Opaque, true);
}
protected override CreateParams CreateParams
{
get
{
// use transparency
CreateParams cp = base.CreateParams;
cp.ExStyle |= 0x00000020; //WS_EX_TRANSPARENT
return cp;
}
}
}
#endregion
private DecorationCanvas _decorationCanvas;
public DecoratedPanel()
{
// add our DecorationCanvas to our panel control
_decorationCanvas = new DecorationCanvas();
_decorationCanvas.Name = "myInternalOverlayPanel";
_decorationCanvas.Size = ClientSize;
_decorationCanvas.Location = new Point(0, 0);
// this prevents the DecorationCanvas to catch clicks and the like
_decorationCanvas.Enabled = false;
_decorationCanvas.Paint += new PaintEventHandler(decoration_Paint);
Controls.Add(_decorationCanvas);
}
protected override void Dispose(bool disposing)
{
if (disposing && _decorationCanvas != null)
{
// be a good citizen and clean up after yourself
_decorationCanvas.Paint -= new PaintEventHandler(decoration_Paint);
Controls.Remove(_decorationCanvas);
_decorationCanvas = null;
}
base.Dispose(disposing);
}
void decoration_Paint(object sender, PaintEventArgs e)
{
// --- PAINT HERE ---
e.Graphics.DrawLine(Pens.Red, 0, 0, ClientSize.Width, ClientSize.Height);
}
protected override void OnControlAdded(ControlEventArgs e)
{
base.OnControlAdded(e);
if (IsInDesignMode)
return;
// Hook paint event and make sure we stay on top
if (!_decorationCanvas.Equals(e.Control))
e.Control.Paint += new PaintEventHandler(containedControl_Paint);
ResetDecorationZOrder();
}
protected override void OnControlRemoved(ControlEventArgs e)
{
base.OnControlRemoved(e);
if (IsInDesignMode)
return;
// Unhook paint event
if (!_decorationCanvas.Equals(e.Control))
e.Control.Paint -= new PaintEventHandler(containedControl_Paint);
}
/// <summary>
/// If contained controls are updated, invalidate the corresponding DecorationCanvas area
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void containedControl_Paint(object sender, PaintEventArgs e)
{
Control c = sender as Control;
if (c == null)
return;
_decorationCanvas.Invalidate(new Rectangle(c.Left, c.Top, c.Width, c.Height));
}
protected override void OnResize(EventArgs eventargs)
{
base.OnResize(eventargs);
// make sure we're covering the panel control
_decorationCanvas.Size = ClientSize;
}
protected override void OnSizeChanged(EventArgs e)
{
base.OnSizeChanged(e);
// make sure we're covering the panel control
_decorationCanvas.Size = ClientSize;
}
/// <summary>
/// This is marked internal because it gets called from the designer
/// to make sure our DecorationCanvas stays on top of the ZOrder.
/// </summary>
internal void ResetDecorationZOrder()
{
if (Controls.GetChildIndex(_decorationCanvas) != 0)
Controls.SetChildIndex(_decorationCanvas, 0);
}
private bool IsInDesignMode
{
get
{
return DesignMode || LicenseManager.UsageMode == LicenseUsageMode.Designtime;
}
}
}
/// <summary>
/// Unfortunately, the default designer of the standard panel is not a public class
/// So we'll have to build a new designer out of another one. Since Panel inherits from
/// ScrollableControl, let's try a ScrollableControlDesigner ...
/// </summary>
public class DecoratedPanelDesigner : ScrollableControlDesigner
{
private IComponentChangeService _changeService;
public override void Initialize(IComponent component)
{
base.Initialize(component);
// Acquire a reference to IComponentChangeService.
this._changeService = GetService(typeof(IComponentChangeService)) as IComponentChangeService;
// Hook the IComponentChangeService event
if (this._changeService != null)
this._changeService.ComponentChanged += new ComponentChangedEventHandler(_changeService_ComponentChanged);
}
/// <summary>
/// Try and handle ZOrder changes at design time
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void _changeService_ComponentChanged(object sender, ComponentChangedEventArgs e)
{
Control changedControl = e.Component as Control;
if (changedControl == null)
return;
DecoratedPanel panelPaint = Control as DecoratedPanel;
if (panelPaint == null)
return;
// if the ZOrder of controls contained within our panel changes, the
// changed control is our control
if (Control.Equals(panelPaint))
panelPaint.ResetDecorationZOrder();
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
if (this._changeService != null)
{
// Unhook the event handler
this._changeService.ComponentChanged -= new ComponentChangedEventHandler(_changeService_ComponentChanged);
this._changeService = null;
}
}
base.Dispose(disposing);
}
/// <summary>
/// If the panel has BorderStyle.None, a dashed border needs to be drawn around it
/// </summary>
/// <param name="pe"></param>
protected override void OnPaintAdornments(PaintEventArgs pe)
{
base.OnPaintAdornments(pe);
Panel panel = Control as Panel;
if (panel == null)
return;
if (panel.BorderStyle == BorderStyle.None)
{
using (Pen p = new Pen(SystemColors.ControlDark))
{
p.DashStyle = System.Drawing.Drawing2D.DashStyle.Dash;
pe.Graphics.DrawRectangle(p, 0, 0, Control.Width - 1, Control.Height - 1);
}
}
}
}
}