We are using Delphi 7 enterprise edition, application is build on windows XP, testing on both Windows XP and Windows 7.
In an application we maintain, something strange is happening. For some reason hitting the "-" key (qwerty layout, between "0" and "=" keys on top) does not register at all.
We checked in the OnKeyDown of the edit we found it with, the OnKeyDown of the form (with and without key preview) and even the ProcessMessage routine, but the event for this key never reaches the application.
We get the same results for OnKeyPress.
Yes, the "-" key on the numpad DOES work. Also, this behavior is only seen in this application, but if we create a new application with only the OnKeyDown of the default form in unit1.pas implemented. it does work.
So somehow we managed to tell the application to properly ignore this one key.
Does anyone have an idea how this could be (un)done?
David's comment is on the right track; You can (with version control) strip back the app until you understand what is going on. However I think that you need to understand the following concepts as well:
OnKeyDown event in a form is not the only place that keyboard shortcuts could go. You should find out where else it's going to, which is why Sertac's comment is there.
It is possible that something OUTSIDE your application is trapping that keyboard key (although this is more common with Control or Alt + Key combinations).
It is possible that something inside your form, or elsewhere in your application is grabbing that key and consuming it.
There is a good article here about KeyPreview, you need to understand that too.
Related
I'm showing where a file has been saved by using 'Showmessage' (in Win 7).
When the file path is long it gets truncated and elipsis get inserted.
eg
the path
C:\Users\Admin\Documents\SubFolderOne\AnotherSubFolder\MyFile.csv
gets displayed as
C:\Users\Admin\Documents\SubFolderOne\Ano...\MyFile.csv
Is there a way to make the message box wider and show all of the filename and path?
I have read this
http://zarko-gajic.iz.hr/displaying-long-non-breakable-text-file-path-in-messagedlg-truncationellipsis-issues/
which explains some of the reasoning and gives a rather unsatisfactory method for a TTaskDialog and I also I realise I could make my own form to act in the same way as Showmessage but I am wondering if there is a simpler solution using just Showmessage.
Is a simpler solution using just ShowMessage?
No there is not.
I can think of three obvious approaches, although doubtless there are more.
Create your own dialog
There's nothing particularly magical about a dialog. You can perfectly well create them yourself, and so have complete control over their appearance. The downside of course is that it can be hard to match the native platform appearance. Especially when you consider all the different Windows versions that you are typically expected to support.
Use CreateMessageDialog and customise this Delphi form
You can call the RTL function CreateMessageDialog to obtain a Delphi form that can be used to display your message dialog. You then have the opportunity to customize this dialog in any way you please.
Use the task dialog API
The task dialog API, introduced in Vista, affords control of the dialog width. Call TaskDialogIndirect, and specify a non-zero value for cxWidth.
Before ShowMessage put:
UseLatestCommonDialogs:= false;
I use Delphi 10.2 and it works.
I have a Windows console app created with Embarcadero XE 6 (in fact converted from a Borland C++Builder5 project). It has a single form with a few buttons and edit controls. All these controls have set TabStop=True and appropriate TabOrder's. However, pressing Tab in runtime when the form is shown does not do anything (it just produces a sound when a cursor/focus is in an Edit control and does nothing when a button is focused).
I have read in docs that Tab order would not work unless the Parent of the form is set. However, this is the only VCL form (the other windows are the console and the GLUT window), so there is no VCL parent AFAIK. I tried to set
Parent=Application->MainForm;
in the Form's constructor, but the Application->MainForm is also NULL. Any ideas?
Your problem is that you don't have a message loop. This is because console applications are not expected to have windows and do not come with message loops by default.
You can run a message loop by calling:
Application->Run();
However this will probably stop the console part of your application from working properly. How can your main thread service the console synchronously and the asynchronous GUI message loop at the same time?
I suspect you will need to have a more serious re-think of your application design.
Regarding your update, it seems that you do have a message loop, but it is the message loop for the GLUT framework. The VCL framework requires its message loop to handle dialog messages like TAB key presses.
It's plausible that running the VCL message loop in place of the GLUT message loop would give better results. But it's quite likely that would just break the GLUT part of the app.
Trying to run two incompatible GUI frameworks out of a single message loop is hard to get right. There's probably no quick fix here. You'll need to dig deeper. Perhaps it would be best to give up on the VCL and stick to the one GUI framework.
Can I get a little code example to use DDE as a server? I know how to use the client part, but can't figure setting up my app to act as a server and receive data.
Have a look in your Delphi installation for a folder called DDEDemo. It's a DDE project that Delphi use to ship with (I'm not 100% sure it's still included, but have a look). The demo includes a DDE client and server.
Edit - Try this link for some example code.
It is so easy to use the DDE server that you don't even need sample code. You can do it just at designtime inside the Delphi form designer:
To create a server that sends out data:
Drop a TDDEServerConv and
TDDEServerItem on your form or data
module.
Connect the server item to
the server conversation (set
DDEServerItem1.ServerConv=DdeServerConv1
using object inspector, there is a
drop down list, but double clicking
it is enough).
Set the DDEServerItem.Text value to some valid text value (ie 'A')
To receive data, you might want to have macros that are executed by the DDE client that pass data to the server. For this you use the DdeServerConv.OnExecuteMacro event. Try dumping the parameter Msg:TStrings to a memo like this:
Memo1.Lines.Assign(Msg);
Now save and run your project.
To test it in excel type in:
=Project1|DdeServerConv1!DdeServerItem1
The excel dde client syntax parts are Application name followed by vertical bar, conversation name, followed by exclamation mark, then item name.
And you will see the value (A, or whatever you put into the Text property in the item) appear in Excel.
That's a working single item DDE server without any code written by you.
I generally find that I create the conversations and the items at runtime, instead of at designtime, in a real world scenario that is more useful for me.
For older (non unicode) Delphi versions there is also a full featured commercial product called Django that helps a lot with DDE work.
I think also you might be looking for information on how to write a "DDE Poke" command handler on the delphi side. I don't have a demo for that. I tried it, and the obvious things didn' quite work right for me (the item on your server has an OnPoke event, I wrote a simple client, called PokeData, and it didn't work).
I have a form and I've passed its handle to the OpenGL class to draw. I want to get keyboard commands from the user but it seems the procedures for getting the keys doesn't run (I've tested it). Although, I am using OnMouseDown with no problem at all.
Is there anything I am missing here? Anyone has a solution?
It's been ages since I used VCL (with C++Builder 3), but if it's still the same as in the old days, you might want to set KeyPreview on your form to True. That will cause the form to receive events that normally would only go to controls.
I put a TLinkLabel on my form, filled it in with a caption including a valid HTML link, and got some nice blue underlined text. When I ran the program, I expected it to invoke Firefox (my default browser) and open the link automatically. Apparently that's not the case.
The helpfile says I have to code this in an OnLinkClick event handler. It doesn't say anything about how to do that, though. It'll pass in a string value called "Link". How do I say "invoke the default browser and have it open Link"?
You can call ShellExecute.
I wrote this method for generic calls, and should works in your case.
procedure ShellOpen(const Url: string; const Params: string = '');
begin
ShellAPI.ShellExecute(0, 'Open', PChar(Url), PChar(Params), nil, SW_SHOWNORMAL);
end;
In your code you should call this
procedure TForm1.LinkLabelClick(Sender: TObject);
begin
ShellOpen(LinkLabel.Caption);
end;
I have all sorts of problems with TLinkLabel that ships with delphi 2010.
a) The control does not render as a hyperlink but as a simple label text on the form. b) the cursor does not change to point out this is a link even though I set the Cursor property. c) the OnLinkClick event does not fire at all.
I am working on windows 7.
So, as far as I am concerned, TLinkLabel does nothing as it should and is useless. ShellExecute is the only solution and must be placed in the OnClick event.
TLinkLabel provides a label that looks like a link. It's your job as the programmer to make it act like a link because only you can know what links are supposed to act like in your program. You wanted the label to automatically open the user's default Web browser using the URL in the label, but that's not the only thing links do. For example:
Internet Explorer is not my default browser, but when I click a link in Internet Explorer, I do not expect the linked page to open in Firefox.
When I click a link in the help program, I expect the linked topic to appear in the help program, not in any Web browser at all.
The preference pages in Eclipse are very complicated. Settings on one page are sometimes related to settings on another page. There are links on those pages that take the user directly to the related page. There is no URL and no HTML involved in this case, and yet they're still labels with underlined text.
Some programs try to offer a choice between opening links in new windows versus re-using old windows. You can't implement that feature without knowing which browser is in use. Your program might offer the user a choice to ignore the default browser setting and always use a specific one. To do that, your UI control can't make too many assumptions about what the program is supposed to do.
I'm guessing you're referring to a TLinkLabel control that comes with Delphi. (My versions don't have such a component.) I imagine that the Delphi control is meant to mimic the one in the .Net class library. It can hold multiple links, and each link can do something different.
If you want a control that always does the shell's default action for URLs, then consider using a different TLinkLabel; the one by Alexander Bach does exactly what you expected. It's from Delphi 3, but it should work unmodified in all later versions as well, including Delphi 2009. If you look at the code, you'll see how it works. It simply calls ShellExecute, as Cesar's answer demonstrates.
LOL, it's funny. So instead of setting crHandPoint as cursor, colored and underlined font and filling the OnClick event to standard TLabel we have component that knows link tag and which at all I need to supply with same On(Link)Click event :))
Only thing it is good for is that it makes easier to embed link into some text and that it is using system style of link...
p.s.: really you have to put Some text with link into the Caption and setup OnLinkClick to that ShellExecute...
I use a control called TInternetLabel instead. It does exactly what you want: on click it opens the browser so you don't have to put code in the OnClick event.
I tried this solution but it still gave problems in Delphi XE4, probably becasue ShellOpen does not understand the HTML-code in the Caption.
What worked for me was a combination of Cesar Romero (the basic code), Adam Feistner (The HTML-code in the Caption) and an older solution:
Put the URL in the HINT field.
Change the line: ShellOpen(LinkLabel.Caption);
to
ShellOpen(LinkLabel.Hint);
This worked for me.