Re: WinForms - Detect End of RichTextBox - C# Discussion Boards

16-Nov-11 2:40

I have multiple RichTextBox controls which are set up as "pages" in a document. The size of each RTB is fixed. How can I tell, when the user types or presses ENTER or anything, if the input must move to a new page? The RTBs can of course have various formatting, font sizes, etc. I cannot figure it out. Perhaps I looked over it in a Google search but I could not find anything similar no matter where I looked. It has been puzzling me for a few days now. Hehe.

Thanks in advance!

djj55: Nice but may have a permission problem
Pete O'Hanlon: He has my permission to run it.

V.16-Nov-11 3:56

16-Nov-11 3:56

didn't vote you down, but my guess is the person in question did so because your question wasn't really clear. What do you mean with pages? What is the exact problem and what did you do to try to solve it? What do you mean with fixed size? etc...
Remember, we're not working on your project and don't have a clue about your terminology to start with.

Matt U.16-Nov-11 4:48

16-Nov-11 4:48

Wow. I guess I should not ask questions when I am terribly sleep deprived. Anyhow, I should clarify the question now.

I have a panel which contains "pages". Each page is a RichTextBox control which I create at a specific size. I set the size at 8.5 * DpiX by 11 * DpiY, which, from what I read, is like 8.5" x 11" on the screen. This size is fixed, meaning the size of the RTB will never change.

The functionality I wish to achieve is similar to that of Microsoft Word, in which the user types on a page (RTB control). And once the text reaches the bottom of the RTB's bounds, I would like to move the "offending" text (the text which does not fit in that particular RTB) to a new page/RTB, which is placed below the original page. I have already implemented inserting pages and such, by adding a new RTB control to the container panel. This works as expected.

I have done some more digging and I found the RTB event called "ContentsResized". MSDN says "Occurs when contents within the control are resized." After playing with this event I have discovered that I can detect when the last line goes beyond the RTB's height. Here is what I have:

MuRichTextBox page = (MuRichTextBox)sender;
int topMargin = (int)(page.TopTextMargin * DpiY);
int bottomMargin = (int)(page.BottomTextMargin * DpiY);

if (page.Lines.Length > 0 && e.NewRectangle.Height > (page.Height - (topMargin + bottomMargin)))
{
    // Move the last line to a new page
    if (page == this._pages[this._pages.Count - 1])    // Add a new page
        this.InsertPage();
}

DpiY is retrieved from:

Graphics g = page.CreateGraphics();
float DpiY = g.DpiY;

When I use this a new page is inserted. But I am not sure how to move the "offending" line from the first page to the newly inserted page. Is that more clear?

djj55: Nice but may have a permission problem
Pete O'Hanlon: He has my permission to run it.

V.25-Nov-11 3:23

25-Nov-11 3:23

Just saw I never replied on this (apologies for that). Do you still need help on this?
Looks rather complex. The only thing I can think of, is trying to measure the size of the string. I remember that GDI+ could do this based on the string and the font (size, type, etc...). it's hell to find the conversions between points/pixels and actual size in mm, cm, m though.

BobJanova16-Nov-11 6:07

BobJanova

16-Nov-11 6:07

I have been following your series of questions and I wonder if it wouldn't be easier to manage the content and the pagination yourself, with a completely custom control. The RichTextBox isn't that great in the first place, and you're having to do quite a lot of hackery to adjust it for your needs. Measuring, rendering and editing simple text with inline formatting markup is not particularly hard, and if you want to go beyond that (tables, inline images, floating wraparounds etc) the RichTextBox tends to mess them up anyway.

Matt U.16-Nov-11 8:20

16-Nov-11 8:20

Oh, interesting. Thank you for the insight, BobJanova. I will definitely take that into consideration. Currently I am learning how to develop custom controls by extending existing controls. Once I am more comfortable with the whole concept I will likely follow your advice. Do you have any resources in mind at the moment which I could read to learn more about what you are suggesting? I will be doing some research of my own. But any help in the proper direction is appreciated.

Does MS Word likely use something OTHER THAN the RTB? I am not trying to create something that will "rival" Word by any means, I am just trying to achieve some of the fairly basic functionality.

djj55: Nice but may have a permission problem
Pete O'Hanlon: He has my permission to run it.

Pete O'Hanlon16-Nov-11 8:45

Pete O'Hanlon

16-Nov-11 8:45

Matt U. wrote:
Does MS Word likely use something OTHER THAN the RTB?

It certainly does. I'm not sure how true this still is, but up to a couple of versions ago, the Word edit page was actually written in a mix of C and assembly to get the maximum speed possible.

Forgive your enemies - it messes with their heads

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

Matt U.16-Nov-11 8:50

16-Nov-11 8:50

Wow. I never would have guess (obviously), haha. Thanks, Pete. I am currently reading up on rendering my own text and such. Thanks again.

djj55: Nice but may have a permission problem
Pete O'Hanlon: He has my permission to run it.

BobJanova16-Nov-11 23:16

BobJanova

16-Nov-11 23:16

Yes, Word definitely custom renders.

You can find a section about how to develop custom controls from UserControl (in WinForms) in my LineEditor article[^].

I would also recommend reading up on how TeX lays out content if you want to go for anything more complicated than a single text stream.

As a bonus, once you have a layout engine that will work for your custom control, it should be trivial to switch the renderer from painting onto a control to using a printer or creating a fixed output format like EPS or PDF.

Bug in ShowWindow in Windows 7

BillWoodruff16-Nov-11 14:41

BillWoodruff

16-Nov-11 14:41

Assuming you are using a RichTextBox with vertical scrolling turned off, you can detect when entered content exceeds the height of the RTFBox via the ContentsResized Event:

// assume a Form with one RichTextBox
// and one TextBox
private void richTextBox1_ContentsResized(object sender, ContentsResizedEventArgs e)
{
    if (e.NewRectangle.Height > richTextBox1.Height)
    {
        textBox1.Text = e.NewRectangle.ToString();
    }
}

Whether you could adapt this to meet your needs: I don't know.

best, Bill

"I have always wished for my computer to be as easy to use as my telephone; my wish has come true because I can no longer figure out how to use my telephone." Bjarne Stroustrop circa 1990

Axonn Echysttas16-Nov-11 2:08

Axonn Echysttas

16-Nov-11 2:08

Hello everybody. For *two weeks*, each day since I installed Windows 7, I have been struggling to get something to work. Something which worked perfectly ok in XP. It's driving me mad, poisoning my life, ruining my days. Why such a simple task works SO CHAOTICALLY!?

I think I discovered a bug in Windows 7, specifically in the way the ShowWindow function works in the standard theme (Aero).

To demonstrate this, I uploaded 2 C# WinForms applications and their source code.

http://www.axonnsd.org/W/P007/BugsDemo.rar

HideableApplication represents an application which you can hide in the SysTray when you close it. Double clicking the SysTray icon reveals it and right clicking will reveal the "Exit" option.

HideableApplicationRevealer attempts to show HideableApplication's window.

The reason I need to accomplish this task is because I minimize my Total Commander and FireFox to the Tray and I want to bring them back via a HotKey. Total Commander offers such a functionality but it is broken.

On Windows XP I managed to accomplish both these tasks without any problems, using the code I attached.

On Windows 7, the behavior is erratic at best, and non-functional at worst.

When HideableApplication runs inside Visual Studio everything works:
- Trying to reveal it via HideableApplicationRevealer from Visual Studio => SUCCESS
- Trying to reveal it via manual execution of HidebleApplicationRevealer.exe from Debug folder => SUCCESS
- Trying to reveal it via running HideableApplicationRevealer.exe via keyboard shortcut => SUCCESS
- Trying to reveal it via running HIdeableApplicationRevealer.exe via a Scheduled Task with Admin Rights => SUCCESS.

When HideableApplication was executed manually (via .exe from Debug folder) AND Visual Studio IS STARTED, it works if I use admin rights or run it manually:
- Trying to reveal it via HideableApplicationRevealer from Visual Studio => FAIL
- Trying to reveal it via manual execution of HidebleApplicationRevealer.exe from Debug folder => SUCCESS
- Trying to reveal it via running HideableApplicationRevealer.exe via keyboard shortcut => FAIL
- Trying to reveal it via running HIdeableApplicationRevealer.exe via a Scheduled Task with Admin Rights => SUCCESS.
- Trying to reveal it via running HideableApplicationRevealer.exe via keyboard shortcut (start menu) which has been given ADMIN RIGHTS => SUCCESS.

When HideableApplication was executed manually (via .exe from Debug folder) AND Visual Studio HAS BEEN SHUT DOWN: it only works if I run it manually (double click exe):
- Trying to reveal it via manual execution of HidebleApplicationRevealer.exe from Debug folder => SUCCESS
- Trying to reveal it via running HideableApplicationRevealer.exe via keyboard shortcut => FAIL
- Trying to reveal it via running HIdeableApplicationRevealer.exe via a Scheduled Task with Admin Rights => PROBLEMS: Window blinks on the TaskBar instead of being shown!
- Trying to reveal it via running HideableApplicationRevealer.exe via keyboard shortcut (start menu) which has been given ADMIN RIGHTS => SUCCESS.

If it matters, I reproduced this behavior both with the Taskbar in its standard position AND also with it set to AutoHide, in the left of the screen.

Apparently, I need admin rights to show a window, but even like this, it doesn't work right when I use the Scheduled Task workaround (create Scheduled Task with admin rights and invoke the Scheduled Task via system32/schtasks.exe /run /tn "task name"). What happens is that AFTER VISUAL STUDIO IS SHUT DOWN, the window blinks on the TaskBar instead of being shown (and has no focus). It does appear, but it has no keyboard focus, which should NOT happen because I also used the SetForegroundWindow API.

This is exactly what happens when I try to run reveal Total Commander as well: read below, same behavior: blinks on taskbar instead of being shown.

And don't even get me started on the difference in behaviors between when running it from Visual Studio and when running it from its usual C:\MyProjects folder.

My TotalCommanderRevealer and FireFoxRevealer exhibit even stranger behaviors: when starting Visual Studio, the Total Commander app stops working properly. Even if I load NO PROJECT, instead of showing TC to me, it just blinks it on the TaskBar. However if I open the TCRevealer project, it starts working again! If I shut down Visual Studio, it STOPS working UNTIL I RESTART WINDOWS.

The FireFoxRevealer instead of revealing FireFox, does something very strange: it shows a small label in the top-left corner of the screen, usually with something related to the opened tab. I suspect this has to do with the Window Style and the way the ShowWindow function works in Windows 7. However, sometimes it works, showing the actual window. But most of the time it doesn't. And when it stops working, I never get it to work again until certain unknown circumstances occur and it works again. Regardless, this worked pefectly under Windows XP and does not work at all now.

If you wish to reproduce the FireFox issue, use the code I attached: instead of searching for "Hideable Application" text in FindWindow API, search for "MozillaWindowClass", install FireFox 7 or 8 and install the FireFox "Minimize To Tray Revived" addon.

I should also mention that I'm aware of the "ForegroundLockTimeout" registry setting and I have set it to 0 everywhere it appears in the Registry. On Windows XP it is set by default to 0 but in Windows 7 the default value was 200000, which I have changed. Maybe somehow it lingers somewhere??? And Visual Studio, while running, sets it to 200000 when I shut it down, until I restart the computer? I looked in the Registry and it doesn't change, it's still 0. But who knows?

I thank you for helping me... by contributing!

Axonn @ SourceForge ^

problem: popup image onclick gridview image using model popup and web service

Rohit Sharma70616-Nov-11 1:38

Rohit Sharma706

16-Nov-11 1:38

I am sending image path(as image save in folder) from web service like

[System.Web.Services.WebMethod(), System.Web.Script.Services.ScriptMethodAttribute()]
public static string GetDynamicContent(string contextKey)
{
string constr = "Data Source=Subhasish-PC;Initial Catalog=testabhijit;Integrated Security=SSPI;";
string query = "SELECT ImagePath FROM imagetable WHERE id = " + contextKey;

SqlDataAdapter da = new SqlDataAdapter(query, constr);
DataTable table = new DataTable();

da.Fill(table);
string x = table.Rows[0]["ImagePath"].ToString();

return x.ToString();

}

Now at .aspx page i am taking panel and image control, like below

<asp:Panel runat="server" CssClass="modalPopup" ID="panSaving" Style="display: none">
<table cellpadding="0" cellspacing="0" border="0" width="100%">
<tr>
<td>
<asp:Image ID="imgClose" runat="server" ImageUrl='' Height="336" Width="430"/>
</td>
</tr>

</table>
</asp:Panel>

My problem is how i will bind ImageUrl of image control......so that which path is sending at web service i can access. Thank you.

Updating the password handling

Bernhard Hiller15-Nov-11 20:32

Bernhard Hiller

15-Nov-11 20:32

Let us assume a client-server application. The server communicates with a database, which contains a table with users. That table stores the passwords.
Of course, passwords are not stored in clear text. In version 1, MD5 was used.
With version 2, that was changed to SHA-1.
Now a customer with more than a hundred users wants to update from version 1 to version 2.
And suddenly you see a problem: You cannot migrate the passwords because there is no function for calculating the SHA-1 value for a given MD5 value - you need the passwords in clear text which is not available.
How would you handle/avoid such a situation?

Peter_in_278015-Nov-11 20:45

Peter_in_2780

15-Nov-11 20:45

In the new password file, put a header on each record to indicate the hash used, for example

MD5.Fred Smith.qwertukljndfvoijer4tgp[oidjfbvdfv
MD5.Joe Bloggs.lkjrfsgbdqkdfvlkdfv456cxvfth
SHA1Alan Black.345908udfvdf340fgkldrsdfsdfsgb

This allows for graceful migration as passwords are renewed/reissued/whatever.
No claims for originality, but I know this technique works.

Cheers,
Peter

Software rusts. Simon Stephenson, ca 1994.

OriginalGriff16-Nov-11 0:13

OriginalGriff

16-Nov-11 0:13

Gets my five - the only sensible way to handle it.

Ideological Purity is no substitute for being able to stick your thumb down a pipe to stop the water

Reiss16-Nov-11 2:57

Reiss

16-Nov-11 2:57

+5 - To expand on this appraoch, whenever a user logs in successfully you can migrate them silently so that the record is updated to use the new hash, as this is the only time your code would get to see the unhashed value. (I know that you all know this, but it may help someone somewhere to spell it out)

Peter_in_278016-Nov-11 9:53

Peter_in_2780

16-Nov-11 9:53

A good idea, IF you have access to the plaintext credentials. Having such access might create all sorts of security holes, however.

Cheers,
Peter

Software rusts. Simon Stephenson, ca 1994.

Bernhard Hiller16-Nov-11 21:45

Bernhard Hiller

16-Nov-11 21:45

Thanks a lot for your valuable ideas.
The situation is not exactly as described in the scenario above, rather version 2 is available since some time, and now the first customer complained about "lost" passwords - the update script resets them to empty strings.
We do not have a "forgot password" feature which would allow us to generate new passwords and mail them to the users - could be a useful improvement.
I suggested to fix it in a way very similar to your suggestion (an extra column in the user table indicating the method used), and automatically update to the new method as suggested by Reiss.
Thanks also to Luc - his idea could be useful in a future change of password handling.

BobJanova16-Nov-11 3:04

BobJanova

16-Nov-11 3:04

If you don't want to do a piecewise migration, which I agree with the above is the best approach, you have to do a mass password reset, using the email for 'forgot password' for all the users.