WinForms | George Birbilis @zoomicon

HowTo: use a Timer component for delayed execution in WinForms

2013/08/25 George Birbilis Leave a comment

This is my contribution to:

http://stackoverflow.com/questions/303116/system-windows-threading-dispatcher-and-winforms

Sometimes a Timer component is useful and easy to setup in WinForms, just set its interval and then enable it, then make sure the first thing you do in its Tick event handler is to disable itself.

I think Timer runs the code in its own thread, so you may still need to do a BeginInvoke (called upon the WinForm object [this]) to run your Action.

private WebBrowserDocumentCompletedEventHandler handler;
//need to make it a class field for the handler below
//(anonymous delegates seem to capture state at point of
// definition, so they can't capture their own reference)
private string imageFilename;
private bool exit;

public void CaptureScreenshot(
  Uri address = null,
  string imageFilename = null,
  int msecDelay = 0,
  bool exit = false)
{
  handler = (s, e) =>
   {
     webBrowser.DocumentCompleted -= handler; //must do first

     this.imageFilename = imageFilename;
     this.exit = exit;

     timerScreenshot.Interval = (msecDelay>0)? msecDelay : 1;
     timerScreenshot.Enabled = true;
   };

  webBrowser.DocumentCompleted += handler;
  Go(address); //if address == null, will use URL from UI
}

private void timerScreenshot_Tick(object sender, EventArgs e)
{
  timerScreenshot.Enabled = false; //must do first

  BeginInvoke((Action)(() => //Invoke at UI thread
  { //run in UI thread

    BringToFront();
    Bitmap bitmap = webBrowser.GetScreenshot();

    if (imageFilename == null)
      imageFilename = bitmap.ShowSaveFileDialog();

    if (imageFilename != null)
    {
      Directory.CreateDirectory(
        Path.GetDirectoryName(
          Path.GetFullPath(imageFilename)));
               //create any parent directories needed
      bitmap.Save(imageFilename);
    }

    bitmap.Dispose(); //release bitmap resources

    if (exit)
      Close(); //this should close the app, this is main form

  }), null);
}

You can see the above in action at ClipFlair‘s WebCapture tool (http://gallery.clipflair.net/WebCapture, source code at: http://ClipFlair.codeplex.com, see Tools/WebCapture folder) that grabs screenshots from websites.

BTW, if you want to call the executable from command-line make sure you go to Properties of the project and at Security tab turn-off ClickOnce security (else it can’t access command-line).

Categories: Posts Tags: ClipFlair, Delay, HowTo, Screenshot, Threading, Timeout, Timer, UI, WebCapture, WinForms

HowTo: Display version information on WinForm title

2013/08/20 George Birbilis Leave a comment

This is my contribution to
http://stackoverflow.com/questions/7178725/version-number-in-winform-form-text

I’m using the following at the WinForm of the WebCapture tool I’m making for ClipFlair:

public MainForm()
{
  InitializeComponent();
  Version version = Assembly.GetExecutingAssembly().GetName().Version;
  Text = Text + " " + version.Major + "." + version.Minor + 
                " (build " + version.Build + ")"; //change form title
}

Not showing revision number to the user, build number is enough technical info

Make sure your AssemblyInfo.cs ends in the following (remove the version it has there by default) for VisualStudio to autoincrement build and revision number. You have to update major and minor versions yourself at every release (update major version for new features, minor version when you do just fixes):

// Version information for an assembly consists of the following four values:
//
//      Major Version
//      Minor Version 
//      Build Number
//      Revision
//
// You can specify all the values or you can default the Build
// and Revision Number by using the '*' as shown below:
// [assembly: AssemblyVersion("1.0.*")]
[assembly: AssemblyVersion("1.0.*")]

Update: Since now WebCapture is ClickOnce-deployed from the web (also has nice autoupdate support thanks to ClickOnce) and I want to avoid user confusion by showing the published version of the app (as the ClickOnce installation page does) on the WinForm titlebar, I now use the following code instead, based on a relevant post I found on the web:

public MainForm()

{

InitializeComponent();

ShowVersion();

}

private void ShowVersion()

{

Version version = (ApplicationDeployment.IsNetworkDeployed)?

    ApplicationDeployment.CurrentDeployment.CurrentVersion :

    Assembly.GetExecutingAssembly().GetName().Version;

    //if network deployed show published version (as the web install page)


Text = Text + " " + version.Major + "." + version.Minor + "."

                     + version.Build + "." + version.Revision;

                       //change form title

}

BTW, speaking of ClickOnce, I noticed that if at the autoupdate dialog shown when you launch the app from its desktop shortcut (and there’s a new version available) you press “Skip”, it won’t offer you this update anymore when you launch an app (I hope that when an even newer update is there it will prompt you), but you can override that behaviour by going to the installation page for your ClickOnce app (where you installed it from in the first place) and press the “Install” button there.

Categories: Posts Tags: .NET, Automation, ClickOnce, ClipFlair, HowTo, Screenshot, Updates, Version, WebCapture, WinForms

HowTo: Save screenshot of a control hosted on a WinForm

2013/08/20 George Birbilis 1 comment

I’m trying to automate grabbing of activity screenshots from ClipFlair Activity Gallery, but most command-line screen capturing tools, like SiteShoter and IECapt fail to get an image from Silverlight content (they get just a background color).

Some other opensource tool that I could tweek was ThumbPage, but that didn’t support command-line and needed to disable Silverlight hardware acceleration in the webpage source (that is not define enableGPUAcceleration Silverlight param or set it to false) to grab the Silverlight content too in the image. This is probably because that tool was written in VB6 and must be using plain GDI instead of GDI+ or other newer graphics API, but I’m not sure if that’s the issue with the h/w acceleration.

So, I started making my own WinForms-based tool in Visual Studio. The following sample code is based on ArsenMkrt’s reply at StackOverflow, but this one allows you to capture a control in your form (my tool has a WebBrowser control in it and want to capture just its display). Note the use of PointToScreen method:

//Project: WebCapture
//Filename: ScreenshotUtils.cs
//Author: George Birbilis (http://zoomicon.com)
//Version: 20130820

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

namespace WebCapture
{
  public static class ScreenshotUtils
  {

    public static Rectangle Offseted(this Rectangle r, Point p)
    {
      r.Offset(p);
      return r;
    }

    public static Bitmap GetScreenshot(this Control c)
    {
      return GetScreenshot(new Rectangle(c.PointToScreen(Point.Empty), c.Size));
    }

    public static Bitmap GetScreenshot(Rectangle bounds)
    {
      Bitmap bitmap = new Bitmap(bounds.Width, bounds.Height);
      using (Graphics g = Graphics.FromImage(bitmap))
        g.CopyFromScreen(new Point(bounds.Left, bounds.Top), 
                         Point.Empty, bounds.Size);
      return bitmap;
    }

    public const string DEFAULT_IMAGESAVEFILEDIALOG_TITLE = "Save image";
    public const string DEFAULT_IMAGESAVEFILEDIALOG_FILTER = 
"PNG Image (*.png)|*.png|JPEG Image (*.jpg)|*.jpg|Bitmap Image (*.bmp)|
*.bmp|GIF Image (*.gif)|*.gif";

//*** NOTE: the string above is a single line, split it for posting here ***//

    public static SaveFileDialog GetImageSaveFileDialog(
      string title = DEFAULT_IMAGESAVEFILEDIALOG_TITLE, 
      string filter = DEFAULT_IMAGESAVEFILEDIALOG_FILTER)
    {
      SaveFileDialog dialog = new SaveFileDialog();

      dialog.Title = title;
      dialog.Filter = filter;

      return dialog;
    }

    public static void ShowSaveFileDialog(this Image image, 
                                          IWin32Window owner = null)
    {
      using (SaveFileDialog dlg = GetImageSaveFileDialog())
        if (dlg.ShowDialog(owner) == DialogResult.OK)
          image.Save(dlg.FileName);
    }

  }
}

Note the “using” clause above, it makes sure that the local variable g of type Graphics is Disposed immediately after the respective clause exits, instead of leaving any allocated resources for the garbage collector to handle. Plus the compiler makes sure the “g” variable isn’t use at the following code in that method by mistake (which could occur if you disposed it there by hand instead).

Having the Bitmap object you can just call Save on it:

private void btnCapture_Click(object sender, EventArgs e)
{
  webBrowser.GetScreenshot().Save("C://test.jpg", ImageFormat.Jpeg);
}

The above assumes the Garbage Collector (aka GC) will grab the bitmap, but maybe it’s better to assign the result of someControl.getScreenshot() to a Bitmap variable, then dispose that variable manually when finished, especially if you’re doing this grabbing often (say you have a list of webpages you want to load and save screenshots of them):

private void btnCapture_Click(object sender, EventArgs e)
{
  Bitmap bitmap = webBrowser.GetScreenshot();
  bitmap.ShowSaveFileDialog();
  bitmap.Dispose(); //release bitmap resources
}

Update:

Now WebCapture tool is ClickOnce-deployed from the web (also has nice autoupdate support thanks to ClickOnce) and you can find its source code at http://ClipFlair.codeplex.com.

Speaking of ClickOnce, I noticed that if at the autoupdate dialog shown when you launch the app from its desktop shortcut (and there’s a new version available) you press “Skip”, it won’t offer you this update anymore when you launch an app (I hope that when an even newer update is there it will prompt you), but you can override that behaviour by going to the installation page for your ClickOnce app (where you installed it from in the first place) and press the “Install” button there.

Categories: Posts Tags: .NET, ClickOnce, ClipFlair, Controls, GDI+, HowTo, IE, Screenshot, Tools, WebCapture, Webpage, WinForms

Save file dialog with Encoding dropdown

2007/03/25 George Birbilis Leave a comment

found a nice Save file dialog for .NET that adds an Encoding dropdown

http://www.codeproject.com/csharp/getsavefilename.asp?forumid=96342&select=1958425&df=100&msg=1958425

see discussion at the end of that article for my VB.net version of that C# code, with some fixes and enhancements (I recently reworked all that into an even better dialog, which accepts/returns a System.Text.Encoding type and shows the list of all encodings provided by the .NET rutime [this includes, apart from the various Unicode flavours, all installed codepages at the OS as it seems]. If interested on it contact me privately to send you a trial)

only glitch is that on XP at the last shortcut folder button on the left handside of the dialog, the bottom part doesn’t show exactly right (maybe not noticeable by most people) when hovering. Haven’t tried it on Vista, hope it works ok there too