Re: PrintDocument PrintPage event - a real answer - C# Discussion Boards

PrintDocument PrintPage event

29-Dec-03 9:32

Looks okay, but keep in mind that you're just using some of the same concepts as an ActiveX container because there's a lot of good ideas in there. If you even declare many of the same interfaces, you could even interop your components with other COM containers (like Word), or host other COM objects.

Basically, having an understanding of how containers work will be very helpful in your quest to create such a UI.

Yaron K.28-Dec-03 20:36

Yaron K.

28-Dec-03 20:36

Hi
When previewing a document using the PrintDocument class: when i receive a PrintPage event, how can I tell if it's for printing on the screen or the printer? I want a slightly different output when printing to the printer.

Thanks

Re: PrintDocument PrintPage event

Heath Stewart29-Dec-03 4:58

29-Dec-03 4:58

No, because the whole idea of a print preview is to preview what will be printed! Why would you do anything different? Not only does it not make sense, it inconsistent with every other program your users will use.

If you really must, you'll have to keep some boolean flag or something similar. Your app should know when the Print and Print Preview buttons were clicked (or whatever you use) so you can determine what to draw based on the state of that flag.

In any case, there's just really no good way to tell based on the PrintPageEventArgs, or the PrintEventArgs for that matter. The properties would be the same for both screen and print, since the Graphics object is supposed to be created to match the printer on which the PrintDocument will be printed (i.e., scaling, twips, etc.).

Bryan White29-Dec-03 14:58

Bryan White

29-Dec-03 14:58

Do not presume to know the mind of someone asking an apparently stupid question. There is a school of thought that says that there are no stupid questions, only stupid answers.

I beg to differ about:
- there being no good reason to act differently.
- there being no good way to tell the difference.

Now, why would I want Print Preview to be different? Because my graphics lines @ 1200 dpi are TOO THIN to show even at 500% Zoom ! So I want to use thicker lines in print preview (and it's also quicker generating a page of bitmapped graphics @ 200dpi rather than 1200dpi).

I don't like flags. The idea of OO stuff is encapsulation.

Good News:
The PrintDocument passed as object sender to XX_PrintPage contains a member 'PrintController' which has a member 'underlyingController' which has a type of {System.Drawing.Printing.PreviewPrintController} or {System.Drawing.Printing.StandardPrintController}.

Bad News:
This is supposed to be hidden from you (thank you Bill and your people who can't think outside the square and mutter "Why would you do anything different").

Good News:
Use Reflection!
//using System.Reflection;
PrintDocument PD = sender as PrintDocument;
PrintControllerWithStatusDialog PC = PD.PrintController as PrintControllerWithStatusDialog;
FieldInfo FI = PC.GetType().GetField("underlyingController", BindingFlags.NonPublic | BindingFlags.Instance);
PreviewPrintController PPC = FI.GetValue(PC) as PreviewPrintController;

Now, if PPC is not null, it's PrintPreview.
If PPC is null, it's not PrintPreview.

Bad News:
It's ugly, brittle, hardly polymorphic, uses undocumented features of dotNet Framework and might stop working in a future release.
Maybe it's not a good way, but it's better than no way.

Good News:
It works for me, and I hope it does for you, too.

Regards

Brewman

Yaron K.29-Dec-03 19:57

Yaron K.

29-Dec-03 19:57

Worked like a charm. many thanks!!!

Heath Stewart30-Dec-03 3:24

30-Dec-03 3:24

Bryan White wrote:
There is a school of thought that says that there are no stupid questions, only stupid answers.

...and this would be a stupid school to attend. There is stupid questions, and I never said that this original question was stupid. Stupid questions are ones that we get in this - and every other forum - on a somewhat regular basis, like "What does method X do?" This question could easily be answered by simply typing it in the index of your help system, either the MSDN Library that is installed (or through an MSDN Library subscription or higher), or with MSDN Online. It's not so much that the question itself is stupid, just that asking it is stupid because developers should at least be able to answer such simple questions for themselves.

Bryan White wrote:
I don't like flags. The idea of OO stuff is encapsulation.

Is there any reason that part of such encapsulation is not using some sort of state flags? MANY of the implementations in the class library - especially those that wrap the Windows Common Controls - use state flags / variables and act accordingly. It's just part of the encapsulation.

As far as the rest of your reply goes, you have discovered a much better way of determining the output device. While reflection can often times be ugly, it many cases it is necessary. Kudos! Smile | :)

Bryan White4-Jan-04 9:47

Bryan White

4-Jan-04 9:47

You wrote
"
Bryan White wrote:
I don't like flags. The idea of OO stuff is encapsulation.

Is there any reason that part of such encapsulation is not using some sort of state flags? MANY of the implementations in the class library - especially those that wrap the Windows Common Controls - use state flags / variables and act accordingly. It's just part of the encapsulation.
"

I have no problem with flags describing an objects INTERNAL state. You are correct, and I agree. I should probably have said "I don't like flags holding the state of, or describing, OTHER objects". This is hinted at by my following sentence (encapsulation).

If (as in this case) an object(PrintDocument) is being activated from another one(either PreviewPrintController/PrintPreviewDialog or StandardPrintController/PrintDialog), then rather than storing a flag about which one activated it (and causing headaches if you decide Preview = !Standard and a third one is added), I feel that it is better to just store the controller/dialog object as a 'parent object'. Then, Microsoft decided to specifically hide this 'parent object', which I find VERY FRUSTRATING (as you can probably guess from the tone of my earlier response. BTW my own technique for defining an item as "this is public but you probably shouldn't be using it" is to prefix the name with an underscore "_". This may not be part of any standard, but hopefully makes people (and myself in a week's time!) think twice before using it.)

If this hidden member did not exist, then rather than create a flag I would still prefer to:
- create a derived class from PrintDocument (called PrintDocumentWithActivator?) with a member of type object called something like 'parent' or 'activator'.
- store the PrintPreviewDialog(or other activator) object in it
- test this object in the PrintPage event.

I feel that this follows the Open-Closed Principle(OCP) better than a flag. Once the 'activator' object is defined, there need be no further changes in the class if, say, a PrintTo3DEngraverDialog came along later, and the programmer wanted a registered trade mark engraved bottom left rather than a copyright notice printed bottom right.

If the flag was held in the app class, then it would be impossible to decide to how to print the PrintDocument object by just referring to that particular instance; you would need TWO objects to decide (difficult when just one object is passed in an event handler), and in danger of violating the Dependency Inversion Principle(DIP); why should the app know or care how an object is being printed?

This in itself would violate the Interface Segregation Principle(ISP) by polluting the app class with potentially dozens/hundreds of flags for each type of operation that might happen 'lower down'.

Should the PrintDocument be implemented in another application - surprise! The new app needs a flag defined! We now have run into Granularity issues of the Reuse/Release Equivalence Principle(REP) & Common Reuse Principle(CRP).

Yes, flags may be used for INTERNAL states, but NOT for states of OTHER objects. Putting a flag in the app, as suggested by yourself, is NOT a good way to go; the app should neither know nor care which button (Print or PrintPreview) was pressed.

Regards

Brewman

Heath Stewart4-Jan-04 9:54

Using IActiveDesktop in C#

4-Jan-04 9:54

I never said it was a good way! Smile | :)

I agree with you that it isn't good for determining the state of other objects, but it was just a quick and dirty idea that could work if managed correctly (i.e., good synchronization and exception handling).

As I was helping someone else with a similar problem (actually, it might've been the same guy), I did find a way to determine which controller is being used without resorting to reflection. The PrintDocument class has a PrintController property. This could be used in the event handlers (or in OnEventName methods if you encapsulate the PrintDocument) to determine which PrintController - like the PreviewPrintController - is being used as the output device.

Okeno Palmer28-Dec-03 19:01

Okeno Palmer

28-Dec-03 19:01

Greets all,

I'm trying to write an application in C# that will allow me to change to the desktop wallpaper. I would also like to place a calendar control on the Desktop using this application. I tried adding a reference to shell32.dll in Visual Studio 2003 but the IActiveDesktop interface is not listed by VS when I examine the reference.

Any suggestions as to how I may go about getting access to the IActiveDesktop from C#??

.:. Keno .:.

Heath Stewart29-Dec-03 4:48

29-Dec-03 4:48

There's a much simpler way: http://www.c-sharpcorner.com/Code/2002/Sept/ChangeWallpaper.asp[^]

Using the IActiveDesktop interface, you'd have to declare it manually using various attributes from System.Runtime.InteropServices and go to a lot of trouble creating the instance from CLSID_ActiveDesktop (defined in shlguid.h) when only a simple function call is needed. See the link above for an example. This was the 3rd result when I googled for "C# desktop wallpaper".

Okeno Palmer29-Dec-03 5:02

Okeno Palmer

29-Dec-03 5:02

Heath,

Thanks for the reply! I did see that link and it does work for changing hte wallpaper. However I think I may have to go the long way as I would like to have an effect like WebShots where I can have a Calnedar control displayed on the desktop.

Would you recommend I go with C# or C++ to implement this control display? I'd really love to do it with C# to see what is involved though so If you can point me to any useful resources and how to start that would be appreciated.

.:. Keno .:.

Heath Stewart29-Dec-03 5:51

29-Dec-03 5:51

First of all, read the documentation for the System.Runtime.InteropServices elements in the .NET Framework SDK documentation. It's important to understand that. There's also a couple articles about COM interop in .NET that you should read in the articles section of the .NET Framework SDK documentation.

Nick Parker has a pretty good one dealing with some of the issues: http://www.codeproject.com/dotnet/nettocom.asp[^]

You should also be familiar with some basic COM, since you'll be using a lot of this to use the IActiveDesktop interfaces. There are several articles here on CP that should be useful.

Honestly, though, the WebShots calendar is nothing more than a calendar drawn onto an image that is set as wallpaper. It is not an desktop item (at least, not last time I checked). It merely loads an image, paints a calendar on that, saves that image to a temporary spot and sets that as the wallpaper. Again, using the SystemParametersInfo method would be much easier. Just use the System.Drawing classes to load an image (Bitmap class) and draw on it (Graphics class), then save it and use the method. Simple.

Building Office add-ins in C#

Okeno Palmer29-Dec-03 11:12

Okeno Palmer

29-Dec-03 11:12

Great info there Heath!

I thought that Calendar was a control! Well it seems then that I should be able to get this done using C#. I'll have a look on those articles you mentioned. I am currently reading "Essential COM" by Dan Box to learn about COM.

Thanks again for all the info, I'll do some reasing and see what I can brew Smile | :)

.:. Keno .:.

Member 78647328-Dec-03 10:36

Member 786473

28-Dec-03 10:36

Hello all,

A few days ago I invested in Visual C#.NET with a purpose of learning how to build Office add-ins. I purchased the standard, educational edition, not the professional edition which includes VB and C++.

The edition of Visual Studio I have does not have the add-in wizard that the professional edition has.

With that in mind, how can I create my add-ins?

In other words, how do I build add-ins to office without the wizard using the standard edition of Visual C#?

Thank you for your help...: Confused | :confused:

Peter

Re: Building Office add-ins in C#

Michael P Butler28-Dec-03 11:36

Michael P Butler

28-Dec-03 11:36

peterdal1 wrote:
The edition of Visual Studio I have does not have the add-in wizard that the professional edition has.

I've not seen an Office Addin wizard in the Architect version either.

peterdal1 wrote:
With that in mind, how can I create my add-ins?

http://support.microsoft.com/default.aspx?scid=kb;en-us;302901[^]

Michael

Look at what's happened to me-,
I can't believe it myself.
Suddenly I'm up on top of the world,
It should've been somebody else. - The Greatest American Hero (1981)

Re: Building Office add-ins in C#

Member 78647328-Dec-03 11:50

Member 786473

28-Dec-03 11:50

Thanks Michael, the link looks promising, I am looking into it. The Wizard I am talking about is called "Shared Add-in" and can be found by selecting "New Projects" from the file menu, then "Other Projects" and "Extensibility Projects".

All the documentation that I have on add-ins points to this wizard, which I don't have, hence my problem.

Thanks again,

Peter

How to kill Excel process properly?

teagermylk28-Dec-03 10:31

teagermylk

28-Dec-03 10:31

I wrote an application that writes to disk a certain excel document from sql database, then opens it edit.
After user finished editing the document in Excel, the application asks in a dialog if user wants to update the changes to DB. If yes, updates the file in the database.
The problem is, that after Excel window is closed and file updated to db, the Excel process is still running. It can be seen in Process Manager,
and causes incorrect behaviour of new Excel windows. After opening 50 documents, there are 50 processes. That causes serious errors in Excel, up to "OLE library error", which can be cured so far by re-installing Office. Frown | :(

The question is: How to kill Excel properly?
TIA

Here is the code:

private void OpenExcel(string filename)

		{

			System.Diagnostics.Process myproc = new System.Diagnostics.Process();

 

			myproc.EnableRaisingEvents = true;



			//a special exitbox is assigned to each document

			ExitBox windowAfterExit = new ExitBox(filename,this,myproc); 

			myproc.Exited+=new EventHandler(windowAfterExit.Excel_Exited);			



			myproc.StartInfo.WorkingDirectory = Environment.CurrentDirectory;

			myproc.StartInfo.FileName = filename;             

			myproc.StartInfo.Verb = "open";



			//open excel

			myproc.Start();



			// at a moment we can work with one document only

			myproc.WaitForExit();			



		}		



	

public class ExitBox : System.Windows.Forms.Form
		{ 

...

		public void Excel_Exited(object sender,EventArgs e)
		{	
                //Excel exited, so show this window
		this.Visible = true;


		}

		private void Exit()

		{	
			//tried this to kill Excel
			myproc.Dispose();



			//all necessary changes are submitted to Db, so delete the file
			DeleteFile(filename);

			//close the form(hope it disposes all resources too :) )		
			this.Close();
	
		}
	}

WIN32 DrawText() .NET equivalent??

ShaneStump28-Dec-03 8:11

ShaneStump

28-Dec-03 8:11

I am looking for a way to get the equivalent functionality of WIN32's DrawText() API function when used with DT_CALCRECT and DT_WORDBREAK.

I am writing a control that will resize itself vertically on a form when its Text property is changed. I have tried using the Graphics.MeasureString() method and I cannot figure out how to get it to return the height of a string to a fixed width.

Any help would be appreciated.

Happy Holidays,

Shane

Heath Stewart28-Dec-03 9:11

28-Dec-03 9:11

See the StringFormat class (the defaults should do, but you can create your own) and the Graphics.DrawString method, which you can use in the OnPaint method override (always override methods instead of handling events in derived classes, but make sure to call the base class's method in most cases):

protected override void OnPaint(PaintEventArgs e)
{
  RectangleF rectF = GetRectFBoundsForControl(); // Made-up method to
    // get the bounds in which text can be drawn.
  e.Graphics.DrawString("Some multi-line text",
    this.Font,
    new SolidBrush(SystemColors.ControlText),
    rectF,
    StringFormat.GenericDefault); // Or create your own
}

Otherwise, you can always just P/Invoke DrawText, define the DT_CALCRECT and DT_WORDBREAK constants (or enum values) based on the preproc def values, and call the method using the control's HDC, which you can get during the Paint event (override OnPaint when deriving from Control instead):

protected override void OnPaint(PaintEventArgs e)
{
  base.OnPaint(e);
  IntPtr hdc = e.Graphics.GetHdc();
  DrawText(hdc, "Some Text", ...);
  e.Graphics.ReleaseHdc(hdc);
}

You'll also need to define the RECT structure to use in managed code. See the StructLayoutAttribute for details.

ShaneStump28-Dec-03 10:48

ShaneStump

28-Dec-03 10:48

Thanks for responding but you did NOT read what I was asking for.

I wasn't asking how to output text. I am asking how to get the SIZE of the text BEFORE it is displayed (i.e. in WIN32, DrawText(Handle,string,string length,RECT *,DT_WORDWRAP | DT_CALCRECT)).

I have NOT had any luck with the Graphic's class MeasureString() method.

Happy Holidays,

Shane

Nick Parker28-Dec-03 11:02

Nick Parker

28-Dec-03 11:02

ShaneStump wrote:
I have NOT had any luck with the Graphic's class MeasureString() method.

Specifically what problems are you having with MeasureString()? Have you tried to P/Invoke DrawText()?

- Nick Parker
My Blog

ShaneStump28-Dec-03 11:11

ShaneStump

28-Dec-03 11:11

MeasureString() doesn't return what I want (or I can't get it to).

I want it to return the # height of the string if wrapping occurs (if the string requres 5 lines, I want the returned height to be for the 5 lines). I am probably NOT using the right method.

Happy Holidays,

Shane