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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘Delphi’ Category

Delphi; on my research list `Error creating form: Root class not found: “”.`

Posted by jpluimers on 2019/10/03

On my Delphi research list:

[Window Title]
Error

[Content]
Error creating form: Root class not found: "".

[OK]

I think it has to do with form inheritance, but a quick glance didn’t raise any warning signs.

–jeroen

Posted in Conference Topics, Conferences, Delphi, Development, Event, Software Development | 1 Comment »

Terminate threads during application or not?

Posted by jpluimers on 2019/10/02

I got an interesting question a while ago: should an application terminate (anonymous) threads or not?

A problem is that a thread might not execute unless you call WaitFor before Terminate is called. The reason is that the internal function ThreadProc does not start Execute if the thread is already terminated.

The ThreadProc in the System.Classes unit is an ideal place to set breakpoints in order to see which threads might start.

Other useful places to set breakpoints:

  • TAnonymousThread.Execute
  • TExternalThread.Execute

Execute not being called by ThreadProc is a bug, but it is not documented because QC is gone (taking the below entry with it), it is not in QP and the docwiki never got updated.

Given QC has so much information, I am still baffled that Embarcadero took it down.

Sergey Kasandrov (a.k.a. serg or sergworks) wrote in [WayBack] Sleep sort and TThread corner case | The Programming Works about this bug and refers to WayBack: QualityCentral 35451 – TThread implementation doesn’t guarantee that thread’s Execute method will be called at all .

The really bad thing are the WayBack: QualityCentral Resolution Entries for Report #35451 Resolution “As Designed” implying the design is wrong.

In his post, sergworks implemented the Sleep sorting in Delphi. Related:

Note that application shutdown is a much debated topic. Best is to do as little cleanup as possible: your process is going to terminate soon anyway. No need to close handles or free memory: Windows will do that for you anyway. See for instance:

 

Related to waiting:

Related to executing:

–jeroen

Posted in Conference Topics, Conferences, Delphi, Development, Event, Multi-Threading / Concurrency, Software Development, The Old New Thing, Windows Development | Leave a Comment »

Soap Delphi Client end with a timeout for a 1MB call – Stack Overflow

Posted by jpluimers on 2019/09/26

This was a change between IE6 and IE7 on the default time-out decreasing from 3600 seconds to 30 seconds: [WayBack] Soap Delphi Client end with a timeout for a 1MB call – Stack Overflow.

If you want to increase the timeout, then use InternetSetOption. You can get the current value using InternetQueryOption.

In Delphi, THTTPReqResp.Send supports this by setting the various time out options right after creating the request:

    Request := HttpOpenRequest(FInetConnect, 'POST', PChar(FURLSite), nil,
                               nil, nil, Flags, 0{Integer(Self)});
    Check(not Assigned(Request));

    { Timeouts }
    if FConnectTimeout > 0 then
      Check(not InternetSetOption(Request, INTERNET_OPTION_CONNECT_TIMEOUT, Pointer(@FConnectTimeout), SizeOf(FConnectTimeout)));
    if FSendTimeout > 0 then
      Check(not InternetSetOption(Request, INTERNET_OPTION_SEND_TIMEOUT, Pointer(@FSendTimeout), SizeOf(FSendTimeout)));
    if FReceiveTimeout > 0 then
      Check(not InternetSetOption(Request, INTERNET_OPTION_RECEIVE_TIMEOUT, Pointer(@FReceiveTimeout), SizeOf(FReceiveTimeout)));

Related:

–jeroen

Posted in Conference Topics, Conferences, Delphi, Development, Event, SOAP/WebServices, Software Development | Leave a Comment »

does anyone know of any Spring.Container examples (preferably non trivial) th…

Posted by jpluimers on 2019/09/26

Via [WayBack] does anyone know of any Spring.Container examples (preferably non trivial) that show how to build an app with a container just referenced from the Compo… – Russell Weetch – Google+:

Stefan Glienke:

The principle of having a composition root has nothing to do with a particular DI container. Its what you eventually get when following the principle if DI: ask for dependencies – don’t create or look for them yourself (aka service locator).

You did not mention it but I guess you mean a VCL application – now the design of the VCL is not particularly built with DI in mind and thus it can be a bit tricky to hook up the application MainForm to the container to get it injected everything. However there are several examples how to achieve that (mainly by using DelegateTo and doing the Application.CreateForm there).

An example explaining this is for instance in [WayBack] How to initialize main application form in Spring4D GlobalContainer?

Many more can be found through Spring4d DelegateTo and Spring4d DelegateTo CreateForm and

–jeroen

Posted in Delphi, Development, Software Development, Spring4D | Leave a Comment »

How to expose a Delphi set type via Soap – Stack Overflow

Posted by jpluimers on 2019/09/25

Marjan Venema had a great answer at [WayBack] How to expose a Delphi set type via Soap – Stack Overflow.

–jeroen

Posted in Conference Topics, Conferences, Delphi, Development, Event, SOAP/WebServices, Software Development | Leave a Comment »

 
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