I've got a WinForm app that parents Windows of other processes (ex. Google Chrome). I'm using the following code to parent a Windows to my Form, using the Handle returned by [Process].MainWindowHandle.
I'm trying to find the MainWindowTitle of all the Windows that are parented to my Form, so I can display their name on a Label.
When the Window of a WebBrowser is embedded, the Title will change when a different Web Page is selected, switching Tabs.
The code I have for starting the program does work as it should:
ProcessStartInfo ps1 = new ProcessStartInfo(#"C:/Users/Jacob/AppData/Roaming/Spotify/Spotify.exe");
ps1.WindowStyle = ProcessWindowStyle.Minimized;
Process p1 = Process.Start(ps1);
// Allow the process to open it's window
Thread.Sleep(1000);
appWin1 = p1.MainWindowHandle;
spotify = p1;
// Put it into this form
SetParent(appWin1, this.Handle);
// Move the window to overlay it on this window
MoveWindow(appWin1, 0, 70, this.Width / 2, this.Height/2, true);
Since you're willing to use UIAutomation to handle this parenting affair, I propose to handle this using Automation methods entirely. Almost, SetParent still required :).
The class shown here uses the WindowPatter.WindowOpenedEvent to detect and notify when a new Window is opened in the System.
It can be any Window, Console included (still a Window).
This method allows to identify a Window when it's handle is already created, so you don't need an arbitrary time-out or try to use Process.WaitForInputIdle(), which may not have the desired result.
You can pass a list of names of processes to the ProcessNames Property of the class: when any Window that belongs to one of these Processes is opened, UIAutomation detects it and a public event is raised. It notifies the subscribers that one of the Processes in the list has opened a Window, which is the ProcessId of the Owner and the handle of the Windows.
These values are passed in a custom EventArgs class, ProcessStartedArgs when the ProcessStarted event is raised.
Since the Automation Event is raised in a Thread other than the UI Thread, the class captures the SynchronizationContext where the class is created (the UI Thread, since you're probably creating this class in a Form) and marshals the event to that Thread, calling its Post() method passing a SendOrPostCallback delegate.
This way, you can safely pass the Handle of your Form and the Handle of the Window to SetParent().
To retrieve the current Title (Caption) of the parented Window, pass the Handle previously returned in the event argument to the GetCurrentWindowTitle() method. If the Window contains tabbed child Windows, as a Web Browser, this method will return the Title related to the Tab currently selected.
▶ The class is disposable and you need to call its public Dispose() method. This removes the Automation event handler and also all the events in the Invocation List of the public event you have subscribed to. This way, you can use a Lambda to subscribe to the event.
Use a Field to store an instance of this class. Create the instance when needed, passing a List of Process Names you're interested in.
Subscribe to the ProcessStarted event.
When on of these Processes opens a new Window, you'll get a notification and the parenting thing can be performed:
public partial class SomeForm : Form
{
private WindowWatcher watcher = null;
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
watcher = new WindowWatcher();
watcher.ProcessNames.AddRange(new[] { "msedge", "firefox", "chrome", "notepad" });
watcher.ProcessStarted += (o, ev) => {
SetParent(ev.WindowHandle, this.Handle);
MoveWindow(ev.WindowHandle, 0, 70, this.Width / 2, this.Height / 2, true);
string windowTitle = WindowWatcher.GetCurrentWindowTitle(ev.WindowHandle);
};
}
protected override void OnFormClosed(FormClosedEventArgs e)
{
watcher.Dispose();
base.OnFormClosed(e);
}
}
WindowWatcher class:
NOTE: UI Automation assemblies are part of Windows Presentation Framework.
When one of these assemblies is referenced in a WinForms application, the WinForms application will become DpiAware (SystemAware), if it's not already DpiAware.
This can have an impact on the Layout of one or more Forms that is not designed to handle Dpi Awareness changes and notifications.
Requires a Project Reference to:
UIAutomationClient
UIAutomationTypes
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Threading;
using System.Windows.Automation;
public class WindowWatcher : IDisposable
{
private SynchronizationContext context = null;
private readonly SendOrPostCallback eventCallback;
public event EventHandler<ProcessStartedArgs> ProcessStarted;
private AutomationElement uiaWindow;
private AutomationEventHandler WindowOpenedHandler;
public WindowWatcher() {
context = SynchronizationContext.Current;
eventCallback = new SendOrPostCallback(EventHandlersInvoker);
InitializeWatcher();
}
public List<string> ProcessNames { get; set; } = new List<string>();
private void InitializeWatcher()
{
Automation.AddAutomationEventHandler(
WindowPattern.WindowOpenedEvent, AutomationElement.RootElement,
TreeScope.Children, WindowOpenedHandler = new AutomationEventHandler(OnWindowOpenedEvent));
}
public static string GetCurrentWindowTitle(IntPtr handle)
{
if (handle == IntPtr.Zero) return string.Empty;
var element = AutomationElement.FromHandle(handle);
if (element != null) {
return element.Current.Name;
}
return string.Empty;
}
private void OnWindowOpenedEvent(object uiaElement, AutomationEventArgs e)
{
uiaWindow = uiaElement as AutomationElement;
if (uiaWindow == null || uiaWindow.Current.ProcessId == Process.GetCurrentProcess().Id) return;
var window = uiaWindow.Current;
var procName = string.Empty;
using (var proc = Process.GetProcessById(window.ProcessId)) {
if (proc == null) throw new InvalidOperationException("Invalid Process");
procName = proc.ProcessName;
}
if (ProcessNames.IndexOf(procName) >= 0) {
var args = new ProcessStartedArgs(procName, window.ProcessId, (IntPtr)window.NativeWindowHandle);
context.Post(eventCallback, args);
}
}
public class ProcessStartedArgs : EventArgs
{
public ProcessStartedArgs(string procName, int procId, IntPtr windowHandle)
{
ProcessName = procName;
ProcessId = procId;
WindowHandle = windowHandle;
}
public string ProcessName { get; }
public int ProcessId { get; }
public IntPtr WindowHandle { get; }
}
private void EventHandlersInvoker(object state)
{
if (!(state is ProcessStartedArgs args)) return;
ProcessStarted?.Invoke(this, args);
}
~WindowWatcher() { Dispose(false); }
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
protected void Dispose(bool disposing)
{
if (uiaWindow != null && WindowOpenedHandler != null) {
Automation.RemoveAutomationEventHandler(
WindowPattern.WindowOpenedEvent, uiaWindow, WindowOpenedHandler);
}
if (ProcessStarted != null) {
var invList = ProcessStarted.GetInvocationList();
if (invList != null && invList.Length > 0) {
for (int i = invList.Length - 1; i >= 0; i--) {
ProcessStarted -= (EventHandler<ProcessStartedArgs>)invList[i];
}
}
}
}
}
I am working on a Windows Phone 7 app and trying to implement the features of a Windows Phone 8 like wide tiles into it. I achieved it using reflection but when i wanted to update the tile using a ScheduledAgent for a Periodic Task the tile is not getting created.
The scheduled agent OnInvoke code looks like
protected override void OnInvoke(ScheduledTask task)
{
//TODO: Add code to perform your task in background
if (task is PeriodicTask)
{
//Update the tile using Scheduled Task
CreateTileForWindowsPhone.CreateWideTile();
}
NotifyComplete();
}
I created the tile using this code
public class CreateTileForWindowsPhone
{
private static Version TargetedVersion = new Version(7, 10, 8858);
public static bool IsTargetedVersion { get { return Environment.OSVersion.Version >= TargetedVersion; } }
public static void CreateWideTile()
{
if (IsTargetedVersion)
{
try
{
// Get the new FlipTileData type.
Type flipTileDataType = Type.GetType("Microsoft.Phone.Shell.FlipTileData, Microsoft.Phone");
// Get the ShellTile type so we can call the new version of "Update" that takes the new Tile templates.
Type shellTileType = Type.GetType("Microsoft.Phone.Shell.ShellTile, Microsoft.Phone");
// Loop through any existing Tiles that are pinned to Start.
QuotesCollection aq = new QuotesCollection();
Random rand = new Random();
int randNum = rand.Next(0, 163);
//String wideBackStr = "Dont be the same, Be Better.";
String wideBackStr = aq.quotes[randNum];
foreach (var tileToUpdate in ShellTile.ActiveTiles)
{
// Get the constructor for the new FlipTileData class and assign it to our variable to hold the Tile properties.
var UpdateTileData = flipTileDataType.GetConstructor(new Type[] { }).Invoke(null);
// Set the properties.
SetProperty(UpdateTileData, "WideBackgroundImage", new Uri("/images/QuottedWideTile.png", UriKind.Relative));
SetProperty(UpdateTileData, "WideBackContent", wideBackStr);
// Invoke the new version of ShellTile.Update.
shellTileType.GetMethod("Update").Invoke(tileToUpdate, new Object[] { UpdateTileData });
break;
}
}
catch
{
MessageBox.Show("Tile Error Caught");
}
}
}
private static void SetProperty(object instance, string name, object value)
{
var setMethod = instance.GetType().GetProperty(name).GetSetMethod();
setMethod.Invoke(instance, new object[] { value });
}
}
i made a register agent method to register the Periodic Task
private void RegisterAgent()
{
string taskName = "MyTask";
try
{
if (ScheduledActionService.Find(taskName) != null)
{
//if the agent exists, remove and then add it to ensure
//the agent's schedule is updated to avoid expiration
ScheduledActionService.Remove(taskName);
}
PeriodicTask periodicTask = new PeriodicTask(taskName);
periodicTask.Description = "Random Quote Update On Tile";
ScheduledActionService.Add(periodicTask);
}
catch (InvalidOperationException exception)
{
MessageBox.Show(exception.Message);
}
catch (SchedulerServiceException schedulerException)
{
MessageBox.Show(schedulerException.Message);
}
}
and called the register in the app launching
private void Application_Launching(object sender, LaunchingEventArgs e)
{
RegisterAgent();
}
But the wide tile is not being created when i run the app.
Wide tile creation used to work before i used scheduled agents to update the tile. I used to create a wide tile just by calling that function in application launching.
private void Application_Launching(object sender, LaunchingEventArgs e)
{
CreateTileForWindowsPhone.CreateWideTile();
}
WHy is the tile not being created. Am i doing something wrong?
Deployment.Current.Dispatcher.BeginInvoke(
CreateTileForWindowsPhone.CreateWideTile);
I am working on an Oreilly's example
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;
using System.Collections.Generic;
using Given;
// Decorator Pattern Example Judith Bishop August 2007
// Draws a single photograph in a window of fixed size
// Has decorators that are BorderedPhotos and TaggedPhotos that can be composed and added
// in different combinations
namespace Given {
// The original Photo class
public class Photo : Form {
Image image;
public Photo () {
image = new Bitmap("jug.jpg");
this.Text = "Lemonade";
this.Paint += new PaintEventHandler(Drawer);
}
public virtual void Drawer(Object source, PaintEventArgs e) {
e.Graphics.DrawImage(image,30,20);
}
}
}
class DecoratorPatternExample {
// This simple BorderedPhoto decorator adds a colored BorderedPhoto of fixed size
class BorderedPhoto : Photo {
Photo photo;
Color color;
public BorderedPhoto (Photo p, Color c) {
photo = p;
color=c;
}
public override void Drawer(Object source, PaintEventArgs e) {
photo.Drawer(source, e);
e.Graphics.DrawRectangle(new Pen(color, 10),25,15,215,225);
}
}
// The TaggedPhoto decorator keeps track of the tag number which gives it
// a specific place to be written
class TaggedPhoto : Photo {
Photo photo;
string tag;
int number;
static int count;
List <string> tags = new List <string> ();
public TaggedPhoto(Photo p, string t) {
photo = p;
tag = t;
tags.Add(t);
number = ++count;
}
public override void Drawer(Object source, PaintEventArgs e) {
photo.Drawer(source,e);
e.Graphics.DrawString(tag,
new Font("Arial", 16),
new SolidBrush(Color.Black),
new PointF(80,100+number*20));
}
public string ListTaggedPhotos() {
string s = "Tags are: ";
foreach (string t in tags) s +=t+" ";
return s;
}
}
static void Main () {
// Application.Run acts as a simple client
Photo photo;
TaggedPhoto foodTaggedPhoto, colorTaggedPhoto, tag;
BorderedPhoto composition;
// Compose a photo with two TaggedPhotos and a blue BorderedPhoto
photo = new Photo();
Application.Run(photo);
foodTaggedPhoto = new TaggedPhoto (photo,"Food");
colorTaggedPhoto = new TaggedPhoto (foodTaggedPhoto,"Yellow");
composition = new BorderedPhoto(colorTaggedPhoto, Color.Blue);
Application.Run(composition);
Console.WriteLine(colorTaggedPhoto.ListTaggedPhotos());
// Compose a photo with one TaggedPhoto and a yellow BorderedPhoto
photo = new Photo();
tag = new TaggedPhoto (photo,"Jug");
composition = new BorderedPhoto(tag, Color.Yellow);
Application.Run(composition);
Console.WriteLine(tag.ListTaggedPhotos());
}
}
/* Output
TaggedPhotos are: Food Yellow
TaggedPhotos are: Food Yellow Jug
*/
Next Exercise is
Assume that the Photo class was written with Drawer as a plain (not virtual)
method and it cannot be altered. Reconstruct Example 2-2 so that it works
under this constraint
How can i do that ?
My Approach
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using System.Windows.Forms;
using GivenWihInterface;
namespace GivenWihInterface
{
interface IPhoto
{
void Drawer(object sender, PaintEventArgs e);
}
class Photo : Form, IPhoto
{
Image image;
public Photo()
{
image = new Bitmap(#"c:\users\anishmarokey\documents\visual studio 2010\Projects\Design_Pattern_Decorator\DecoratorPattern_RealExample\Images\apple-6.jpg");
this.Text = "Apple";
this.Paint += new PaintEventHandler(Drawer);
}
public void Drawer(object sender, PaintEventArgs e)
{
e.Graphics.DrawImage(image, 20, 20);
}
}
class BorderPhoto : Form, IPhoto
{
IPhoto pho;
Color color;
public BorderPhoto(IPhoto p, Color c)
{
pho = p;
color = c;
this.Paint += new PaintEventHandler(Drawer);
}
public void Drawer(object sender, PaintEventArgs e)
{
pho.Drawer(sender, e);
e.Graphics.DrawRectangle(new Pen(color, 10), 25, 15, 215, 225);
}
}
}
namespace DecoratorPattern_RealExample
{
class DecoratorPatternWithInterface
{
static void Dispaly(GivenWihInterface.IPhoto p)
{
Application.Run((Form)p);
}
static void Main()
{
IPhoto component = new GivenWihInterface.Photo();
Dispaly(component);
component = new GivenWihInterface.Photo();
IPhoto p = new GivenWihInterface.BorderPhoto(component,Color.Red);
Application.Run((Form)p);
}
}
}
is this the correct Way?
Yes, that is an appropriate "decorator" implementation. The only thing I'd question is whether you actually need to inherit from Form, or whether implementing IPhoto is sufficient. Which can only be answered with more context.
Also, the hard-coded (dimensions?) values look like there may be a better way if some existing values are available somewhere.
The example itself is unusual, though - you've had to introduce the interface, which is pretty much as much of a change as you are trying to avoid; and the type handles an event on itself, which is bad practice. I almost wonder if they want you to hook into the event pipeline, but that wouldn't really be a decorator.
I suspect they want you to code against Form rather than the IPhoto you have introduced, which would allow you to decorate lots of things. But you would need to have a known method on Form to call, for example Paint() - except that is an event here, not a method so the name will be different. And again we could hook the event, but that isn't classic decorator usage.
I am looking for ideas on an efficient way to implement a log window for a windows forms application. In the past I have implemented several using TextBox and RichTextBox but I am still not totally satisfied with the functionality.
This log is intended to provide the user with a recent history of various events, primarily used in data-gathering applications where one might be curious how a particular transaction completed. In this case, the log need not be permanent nor saved to a file.
First, some proposed requirements:
Efficient and fast; if hundreds of lines are written to the log in quick succession, it needs to consume minimal resources and time.
Be able to offer a variable scrollback of up to 2000 lines or so. Anything longer is unnecessary.
Highlighting and color are preferred. Font effects not required.
Automatically trim lines as the scrollback limit is reached.
Automatically scroll as new data is added.
Bonus but not required: Pause auto-scrolling during manual interaction such as if the user is browsing the history.
What I have been using so far to write and trim the log:
I use the following code (which I call from other threads):
// rtbLog is a RichTextBox
// _MaxLines is an int
public void AppendLog(string s, Color c, bool bNewLine)
{
if (rtbLog.InvokeRequired)
{
object[] args = { s, c, bNewLine };
rtbLog.Invoke(new AppendLogDel(AppendLog), args);
return;
}
try
{
rtbLog.SelectionColor = c;
rtbLog.AppendText(s);
if (bNewLine) rtbLog.AppendText(Environment.NewLine);
TrimLog();
rtbLog.SelectionStart = rtbLog.TextLength;
rtbLog.ScrollToCaret();
rtbLog.Update();
}
catch (Exception exc)
{
// exception handling
}
}
private void TrimLog()
{
try
{
// Extra lines as buffer to save time
if (rtbLog.Lines.Length < _MaxLines + 10)
{
return;
}
else
{
string[] sTemp = rtxtLog.Lines;
string[] sNew= new string[_MaxLines];
int iLineOffset = sTemp.Length - _MaxLines;
for (int n = 0; n < _MaxLines; n++)
{
sNew[n] = sTemp[iLineOffset];
iLineOffset++;
}
rtbLog.Lines = sNew;
}
}
catch (Exception exc)
{
// exception handling
}
}
The problem with this approach is that whenever TrimLog is called, I lose color formatting. With a regular TextBox this works just fine (with a bit of modification of course).
Searches for a solution to this have never been really satisfactory. Some suggest to trim the excess by character count instead of line count in a RichTextBox. I've also seen ListBoxes used, but haven't successfully tried it.
I recommend that you don't use a control as your log at all. Instead write a log collection class that has the properties you desire (not including the display properties).
Then write the little bit of code that is needed to dump that collection to a variety of user interface elements. Personally, I would put SendToEditControl and SendToListBox methods into my logging object. I would probably add filtering capabilities to these methods.
You can update the UI log only as often as it makes sense, giving you the best possible performance, and more importantly, letting you reduce the UI overhead when the log is changing rapidly.
The important thing is not to tie your logging to a piece of UI, that's a mistake. Someday you may want to run headless.
In the long run, a good UI for a logger is probably a custom control. But in the short run, you just want to disconnect your logging from any specific piece of UI.
Here is something I threw together based on a much more sophisticated logger I wrote a while ago.
This will support color in the list box based on log level, supports Ctrl+V and Right-Click for copying as RTF, and handles logging to the ListBox from other threads.
You can override the number of lines retained in the ListBox (2000 by default) as well as the message format using one of the constructor overloads.
using System;
using System.Drawing;
using System.Windows.Forms;
using System.Threading;
using System.Text;
namespace StackOverflow
{
public partial class Main : Form
{
public static ListBoxLog listBoxLog;
public Main()
{
InitializeComponent();
listBoxLog = new ListBoxLog(listBox1);
Thread thread = new Thread(LogStuffThread);
thread.IsBackground = true;
thread.Start();
}
private void LogStuffThread()
{
int number = 0;
while (true)
{
listBoxLog.Log(Level.Info, "A info level message from thread # {0,0000}", number++);
Thread.Sleep(2000);
}
}
private void button1_Click(object sender, EventArgs e)
{
listBoxLog.Log(Level.Debug, "A debug level message");
}
private void button2_Click(object sender, EventArgs e)
{
listBoxLog.Log(Level.Verbose, "A verbose level message");
}
private void button3_Click(object sender, EventArgs e)
{
listBoxLog.Log(Level.Info, "A info level message");
}
private void button4_Click(object sender, EventArgs e)
{
listBoxLog.Log(Level.Warning, "A warning level message");
}
private void button5_Click(object sender, EventArgs e)
{
listBoxLog.Log(Level.Error, "A error level message");
}
private void button6_Click(object sender, EventArgs e)
{
listBoxLog.Log(Level.Critical, "A critical level message");
}
private void button7_Click(object sender, EventArgs e)
{
listBoxLog.Paused = !listBoxLog.Paused;
}
}
public enum Level : int
{
Critical = 0,
Error = 1,
Warning = 2,
Info = 3,
Verbose = 4,
Debug = 5
};
public sealed class ListBoxLog : IDisposable
{
private const string DEFAULT_MESSAGE_FORMAT = "{0} [{5}] : {8}";
private const int DEFAULT_MAX_LINES_IN_LISTBOX = 2000;
private bool _disposed;
private ListBox _listBox;
private string _messageFormat;
private int _maxEntriesInListBox;
private bool _canAdd;
private bool _paused;
private void OnHandleCreated(object sender, EventArgs e)
{
_canAdd = true;
}
private void OnHandleDestroyed(object sender, EventArgs e)
{
_canAdd = false;
}
private void DrawItemHandler(object sender, DrawItemEventArgs e)
{
if (e.Index >= 0)
{
e.DrawBackground();
e.DrawFocusRectangle();
LogEvent logEvent = ((ListBox)sender).Items[e.Index] as LogEvent;
// SafeGuard against wrong configuration of list box
if (logEvent == null)
{
logEvent = new LogEvent(Level.Critical, ((ListBox)sender).Items[e.Index].ToString());
}
Color color;
switch (logEvent.Level)
{
case Level.Critical:
color = Color.White;
break;
case Level.Error:
color = Color.Red;
break;
case Level.Warning:
color = Color.Goldenrod;
break;
case Level.Info:
color = Color.Green;
break;
case Level.Verbose:
color = Color.Blue;
break;
default:
color = Color.Black;
break;
}
if (logEvent.Level == Level.Critical)
{
e.Graphics.FillRectangle(new SolidBrush(Color.Red), e.Bounds);
}
e.Graphics.DrawString(FormatALogEventMessage(logEvent, _messageFormat), new Font("Lucida Console", 8.25f, FontStyle.Regular), new SolidBrush(color), e.Bounds);
}
}
private void KeyDownHandler(object sender, KeyEventArgs e)
{
if ((e.Modifiers == Keys.Control) && (e.KeyCode == Keys.C))
{
CopyToClipboard();
}
}
private void CopyMenuOnClickHandler(object sender, EventArgs e)
{
CopyToClipboard();
}
private void CopyMenuPopupHandler(object sender, EventArgs e)
{
ContextMenu menu = sender as ContextMenu;
if (menu != null)
{
menu.MenuItems[0].Enabled = (_listBox.SelectedItems.Count > 0);
}
}
private class LogEvent
{
public LogEvent(Level level, string message)
{
EventTime = DateTime.Now;
Level = level;
Message = message;
}
public readonly DateTime EventTime;
public readonly Level Level;
public readonly string Message;
}
private void WriteEvent(LogEvent logEvent)
{
if ((logEvent != null) && (_canAdd))
{
_listBox.BeginInvoke(new AddALogEntryDelegate(AddALogEntry), logEvent);
}
}
private delegate void AddALogEntryDelegate(object item);
private void AddALogEntry(object item)
{
_listBox.Items.Add(item);
if (_listBox.Items.Count > _maxEntriesInListBox)
{
_listBox.Items.RemoveAt(0);
}
if (!_paused) _listBox.TopIndex = _listBox.Items.Count - 1;
}
private string LevelName(Level level)
{
switch (level)
{
case Level.Critical: return "Critical";
case Level.Error: return "Error";
case Level.Warning: return "Warning";
case Level.Info: return "Info";
case Level.Verbose: return "Verbose";
case Level.Debug: return "Debug";
default: return string.Format("<value={0}>", (int)level);
}
}
private string FormatALogEventMessage(LogEvent logEvent, string messageFormat)
{
string message = logEvent.Message;
if (message == null) { message = "<NULL>"; }
return string.Format(messageFormat,
/* {0} */ logEvent.EventTime.ToString("yyyy-MM-dd HH:mm:ss.fff"),
/* {1} */ logEvent.EventTime.ToString("yyyy-MM-dd HH:mm:ss"),
/* {2} */ logEvent.EventTime.ToString("yyyy-MM-dd"),
/* {3} */ logEvent.EventTime.ToString("HH:mm:ss.fff"),
/* {4} */ logEvent.EventTime.ToString("HH:mm:ss"),
/* {5} */ LevelName(logEvent.Level)[0],
/* {6} */ LevelName(logEvent.Level),
/* {7} */ (int)logEvent.Level,
/* {8} */ message);
}
private void CopyToClipboard()
{
if (_listBox.SelectedItems.Count > 0)
{
StringBuilder selectedItemsAsRTFText = new StringBuilder();
selectedItemsAsRTFText.AppendLine(#"{\rtf1\ansi\deff0{\fonttbl{\f0\fcharset0 Courier;}}");
selectedItemsAsRTFText.AppendLine(#"{\colortbl;\red255\green255\blue255;\red255\green0\blue0;\red218\green165\blue32;\red0\green128\blue0;\red0\green0\blue255;\red0\green0\blue0}");
foreach (LogEvent logEvent in _listBox.SelectedItems)
{
selectedItemsAsRTFText.AppendFormat(#"{{\f0\fs16\chshdng0\chcbpat{0}\cb{0}\cf{1} ", (logEvent.Level == Level.Critical) ? 2 : 1, (logEvent.Level == Level.Critical) ? 1 : ((int)logEvent.Level > 5) ? 6 : ((int)logEvent.Level) + 1);
selectedItemsAsRTFText.Append(FormatALogEventMessage(logEvent, _messageFormat));
selectedItemsAsRTFText.AppendLine(#"\par}");
}
selectedItemsAsRTFText.AppendLine(#"}");
System.Diagnostics.Debug.WriteLine(selectedItemsAsRTFText.ToString());
Clipboard.SetData(DataFormats.Rtf, selectedItemsAsRTFText.ToString());
}
}
public ListBoxLog(ListBox listBox) : this(listBox, DEFAULT_MESSAGE_FORMAT, DEFAULT_MAX_LINES_IN_LISTBOX) { }
public ListBoxLog(ListBox listBox, string messageFormat) : this(listBox, messageFormat, DEFAULT_MAX_LINES_IN_LISTBOX) { }
public ListBoxLog(ListBox listBox, string messageFormat, int maxLinesInListbox)
{
_disposed = false;
_listBox = listBox;
_messageFormat = messageFormat;
_maxEntriesInListBox = maxLinesInListbox;
_paused = false;
_canAdd = listBox.IsHandleCreated;
_listBox.SelectionMode = SelectionMode.MultiExtended;
_listBox.HandleCreated += OnHandleCreated;
_listBox.HandleDestroyed += OnHandleDestroyed;
_listBox.DrawItem += DrawItemHandler;
_listBox.KeyDown += KeyDownHandler;
MenuItem[] menuItems = new MenuItem[] { new MenuItem("Copy", new EventHandler(CopyMenuOnClickHandler)) };
_listBox.ContextMenu = new ContextMenu(menuItems);
_listBox.ContextMenu.Popup += new EventHandler(CopyMenuPopupHandler);
_listBox.DrawMode = DrawMode.OwnerDrawFixed;
}
public void Log(string message) { Log(Level.Debug, message); }
public void Log(string format, params object[] args) { Log(Level.Debug, (format == null) ? null : string.Format(format, args)); }
public void Log(Level level, string format, params object[] args) { Log(level, (format == null) ? null : string.Format(format, args)); }
public void Log(Level level, string message)
{
WriteEvent(new LogEvent(level, message));
}
public bool Paused
{
get { return _paused; }
set { _paused = value; }
}
~ListBoxLog()
{
if (!_disposed)
{
Dispose(false);
_disposed = true;
}
}
public void Dispose()
{
if (!_disposed)
{
Dispose(true);
GC.SuppressFinalize(this);
_disposed = true;
}
}
private void Dispose(bool disposing)
{
if (_listBox != null)
{
_canAdd = false;
_listBox.HandleCreated -= OnHandleCreated;
_listBox.HandleCreated -= OnHandleDestroyed;
_listBox.DrawItem -= DrawItemHandler;
_listBox.KeyDown -= KeyDownHandler;
_listBox.ContextMenu.MenuItems.Clear();
_listBox.ContextMenu.Popup -= CopyMenuPopupHandler;
_listBox.ContextMenu = null;
_listBox.Items.Clear();
_listBox.DrawMode = DrawMode.Normal;
_listBox = null;
}
}
}
}
I'll store this here as a help to Future Me when I want to use a RichTextBox for logging colored lines again. The following code removes the first line in a RichTextBox:
if ( logTextBox.Lines.Length > MAX_LINES )
{
logTextBox.Select(0, logTextBox.Text.IndexOf('\n')+1);
logTextBox.SelectedRtf = "{\\rtf1\\ansi\\ansicpg1252\\deff0\\deflang1053\\uc1 }";
}
It took me way too long to figure out that setting SelectedRtf to just "" didn't work, but that setting it to "proper" RTF with no text content is ok.
My solution to creating a basic log window was exactly as John Knoeller suggested in his answer. Avoid storing log information directly in a TextBox or RichTextBox control, but instead create a logging class which can be used to populate a control, or write to a file, etc.
There are a few pieces to this example solution:
The logging class itself, Logger.
Modification of the RichTextBox control to add scroll-to-bottom functionality after an update; ScrollingRichTextBox.
The main form to demonstrate its use, LoggerExample.
First, the logging class:
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;
namespace Logger
{
/// <summary>
/// A circular buffer style logging class which stores N items for display in a Rich Text Box.
/// </summary>
public class Logger
{
private readonly Queue<LogEntry> _log;
private uint _entryNumber;
private readonly uint _maxEntries;
private readonly object _logLock = new object();
private readonly Color _defaultColor = Color.White;
private class LogEntry
{
public uint EntryId;
public DateTime EntryTimeStamp;
public string EntryText;
public Color EntryColor;
}
private struct ColorTableItem
{
public uint Index;
public string RichColor;
}
/// <summary>
/// Create an instance of the Logger class which stores <paramref name="maximumEntries"/> log entries.
/// </summary>
public Logger(uint maximumEntries)
{
_log = new Queue<LogEntry>();
_maxEntries = maximumEntries;
}
/// <summary>
/// Retrieve the contents of the log as rich text, suitable for populating a <see cref="System.Windows.Forms.RichTextBox.Rtf"/> property.
/// </summary>
/// <param name="includeEntryNumbers">Option to prepend line numbers to each entry.</param>
public string GetLogAsRichText(bool includeEntryNumbers)
{
lock (_logLock)
{
var sb = new StringBuilder();
var uniqueColors = BuildRichTextColorTable();
sb.AppendLine($#"{{\rtf1{{\colortbl;{ string.Join("", uniqueColors.Select(d => d.Value.RichColor)) }}}");
foreach (var entry in _log)
{
if (includeEntryNumbers)
sb.Append($"\\cf1 { entry.EntryId }. ");
sb.Append($"\\cf1 { entry.EntryTimeStamp.ToShortDateString() } { entry.EntryTimeStamp.ToShortTimeString() }: ");
var richColor = $"\\cf{ uniqueColors[entry.EntryColor].Index + 1 }";
sb.Append($"{ richColor } { entry.EntryText }\\par").AppendLine();
}
return sb.ToString();
}
}
/// <summary>
/// Adds <paramref name="text"/> as a log entry.
/// </summary>
public void AddToLog(string text)
{
AddToLog(text, _defaultColor);
}
/// <summary>
/// Adds <paramref name="text"/> as a log entry, and specifies a color to display it in.
/// </summary>
public void AddToLog(string text, Color entryColor)
{
lock (_logLock)
{
if (_entryNumber >= uint.MaxValue)
_entryNumber = 0;
_entryNumber++;
var logEntry = new LogEntry { EntryId = _entryNumber, EntryTimeStamp = DateTime.Now, EntryText = text, EntryColor = entryColor };
_log.Enqueue(logEntry);
while (_log.Count > _maxEntries)
_log.Dequeue();
}
}
/// <summary>
/// Clears the entire log.
/// </summary>
public void Clear()
{
lock (_logLock)
{
_log.Clear();
}
}
private Dictionary<Color, ColorTableItem> BuildRichTextColorTable()
{
var uniqueColors = new Dictionary<Color, ColorTableItem>();
var index = 0u;
uniqueColors.Add(_defaultColor, new ColorTableItem() { Index = index++, RichColor = ColorToRichColorString(_defaultColor) });
foreach (var c in _log.Select(l => l.EntryColor).Distinct().Where(c => c != _defaultColor))
uniqueColors.Add(c, new ColorTableItem() { Index = index++, RichColor = ColorToRichColorString(c) });
return uniqueColors;
}
private string ColorToRichColorString(Color c)
{
return $"\\red{c.R}\\green{c.G}\\blue{c.B};";
}
}
}
The Logger class incorporates another class LogEntry which keeps track of the line number, timestamp, and desired color. A struct is used to build a Rich Text color table.
Next, here is the modified RichTextBox:
using System;
using System.Runtime.InteropServices;
namespace Logger
{
public class ScrollingRichTextBox : System.Windows.Forms.RichTextBox
{
[DllImport("user32.dll", CharSet = CharSet.Auto)]
private static extern IntPtr SendMessage(
IntPtr hWnd,
uint Msg,
IntPtr wParam,
IntPtr LParam);
private const int _WM_VSCROLL = 277;
private const int _SB_BOTTOM = 7;
/// <summary>
/// Scrolls to the bottom of the RichTextBox.
/// </summary>
public void ScrollToBottom()
{
SendMessage(Handle, _WM_VSCROLL, new IntPtr(_SB_BOTTOM), new IntPtr(0));
}
}
}
All I am doing here is inheriting a RichTextBox and adding a "scroll to bottom" method. There are various other questions about how to do this on StackOverflow, from which I derived this approach.
Finally, an example of using this class from a form:
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
namespace Logger
{
public partial class LoggerExample : Form
{
private Logger _log = new Logger(100u);
private List<Color> _randomColors = new List<Color> { Color.Red, Color.SkyBlue, Color.Green };
private Random _r = new Random((int)DateTime.Now.Ticks);
public LoggerExample()
{
InitializeComponent();
}
private void timerGenerateText_Tick(object sender, EventArgs e)
{
if (_r.Next(10) > 5)
_log.AddToLog("Some event to log.", _randomColors[_r.Next(3)]);
}
private void timeUpdateLogWindow_Tick(object sender, EventArgs e)
{
richTextBox1.Rtf = _log.GetLogAsRichText(true);
richTextBox1.ScrollToBottom();
}
}
}
This form is created with two timers, one to generate log entries pseudo-randomly, and one to populate the RichTextBox itself. In this example, the log class is instantiated with 100 lines of scroll-back. The RichTextBox control colors are set to have a black background with white and various color foregrounds. The timer to generate text is at a 100ms interval while the one to update the log window is at 1000ms.
Sample output:
It is far from perfect or finished, but here are some caveats and things that could be added or improved (some of which I have done in later projects):
With large values for maximumEntries, performance is poor. This logging class was only designed for a few hundred lines of scroll-back.
Replacing the text of the RichTextBox can result in flickering. I always keep the refresh timer at a relatively slow interval. (One second in this example.)
Adding to #2 above, some of my projects check if the log has any new entries before redrawing the RichTextBox content, to avoid unnecessarily refreshing it.
The timestamp on each log entry can be made optional and allow different formats.
There is no way to pause the log in this example, but many of my projects do provide a mechanism for pausing the scrolling behavior, to allow users to manually scroll, select, and copy text from the log window.
Feel free to modify and improve upon this example. Feedback is welcome.
I would say ListView is perfect for this (in Detail viewing mode), and its exactly what I use it for in a few internal apps.
Helpful tip: use BeginUpdate() and EndUpdate() if you know you will be adding/removing a lot of items at once.
I recently implemented something similar. Our approach was to keep a ring buffer of the scrollback records and just paint the log text manually (with Graphics.DrawString). Then if the user wants to scroll back, copy text, etc., we have a "Pause" button that flips back to a normal TextBox control.
If you want highlighting and color formatting, I'd suggest a RichTextBox.
If you want the auto scrolling, then use the ListBox.
In either case bind it to a circular buffer of lines.