Solved

Focus issues when using DLL assemblies

Posted on 2004-08-20
5
201 Views
Last Modified: 2010-04-15
Firstly let me apologise for the rather vague title, the problem I am encountering is a little difficult to briefly describe.

I have just encountered an interesting focus problem, which after doing some testing & searching I am at a loss to explain (which is why I have allocated 500 points for a working solution)

I have a C# COM object that under certain circumstances will show a form. This is a simple form with 2 buttons (ok, cancel) and a listview. By default the OK button has focus (through code by setting .Focus(), and through design by setting its tab order to 0).

When the form is displayed the button has focus because if I press return the code behind the button is executed (I am not using the AcceptButton property on the form) - the curious problem is how the button is rendered.

Normally if a button has focus a dotted line is drawn just inside the buttons bounds and the button shadow is enhanced. On the COM launched form the shadow is drawn but the inner line is not, but if I tab around to the button again it does have the dotted line.

If I create a .NET assembly and call the function through the framework the button is also rendered incorrectly.

If I add a Main() function to the form and launch it directly then the button is rendered correctly (with the shadow and the dotted line)

Does anybody have any ideas of what direction I should go to find a solution to this problem?

More Info :
The assembly has a entry point function called (this function is marked as public so it can also be called in .NET via referencing):

IsValid(ref int errorcode, ref string errordesc, bool valid)

When using the assembly as COM (in Delphi), I instantiate the DLL (constructor does not perform any code) and then call

myComObj.IsValid(....)

Under certain circumstances this function will launch the dialog described above, using the following code :

if (blah blah blah)
{
 GetUserData gud = new GetUserData();
 gud.ShowDialog();
}
else
{
 ...
}

Simple enough, well I thought so until this focus issue appaeared
0
Comment
Question by:MrEyes
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
5 Comments
 
LVL 4

Expert Comment

by:somnatic
ID: 11850629
you might want to try to send a single tab when the form is loaded.

SendKeys.Send("{TAB}");

funnily, the dottet line will then be there (even if you switch controls around).

Don't know why .. but appearently it works ..
0
 

Author Comment

by:MrEyes
ID: 12097953
Firstly apologies for not replying earlier

The solution suggested by Somnatic is not feasible as in code review this would be considered a hack rather than a real solution.

I am either looking for a real solution or a presentable reason as to why this "feature" exisits.
0
 
LVL 4

Expert Comment

by:somnatic
ID: 12099493
of course it is ...

i checked petzold and co. but couldn't find an explanation for that dotted line ... since nobody else in the company could answer that question it was said to be ok (even if no beautiful).

anyway .. should you ever find out - please let me know :)
0
 
LVL 1

Accepted Solution

by:
DarthMod earned 0 total points
ID: 12142508
Submitted to PAQ with points refunded (500)

DarthMod
Community Support Moderator
0

Featured Post

Ready to get started with anonymous questions?

It's easy! Check out this step-by-step guide for asking an anonymous question on Experts Exchange.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Article by: Ivo
C# And Nullable Types Since 2.0 C# has Nullable(T) Generic Structure. The idea behind is to allow value type objects to have null values just like reference types have. This concerns scenarios where not all data sources have values (like a databa…
This article aims to explain the working of CircularLogArchiver. This tool was designed to solve the buildup of log file in cases where systems do not support circular logging or where circular logging is not enabled
There are cases when e.g. an IT administrator wants to have full access and view into selected mailboxes on Exchange server, directly from his own email account in Outlook or Outlook Web Access. This proves useful when for example administrator want…
Sometimes it takes a new vantage point, apart from our everyday security practices, to truly see our Active Directory (AD) vulnerabilities. We get used to implementing the same techniques and checking the same areas for a breach. This pattern can re…

624 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question