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  • C# method to scale values?

    - by John S
    Hello, I have a value range from 0 to 255. There is a method that returns an array with a min and max values within this range, i.e: 13, 15, 20, 27, 50 ... 240 where 13 is the min and 240 is the max I need to scale these values so that 13 becomes 0 and 240 becomes 255 and scale all the other values between them proportionally. Is there any C# method that does that? thanks!

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  • How to convert image to bitmap code for bluetooth print in iphone

    - by John Patel
    I am interested to print image from iPhone programmatically using bluetooth printer device. In one of the sample code I have implemented code for Text print but in that sample I am not getting how to convert image into format, like unsigned char buffer3[796]={ 0x55 , 0x66 , 0x77 , 0x88 , 0x44 , 0x1B , 0x58 , 0x31 , 0x19, 0x20, 0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x80 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x01 ,0xC0 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x01 ,0x80 ,0x00 ,0x03 ,0x60 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x03 ,0xA0 ,0x00 ,0x07 ,0xB0 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x05 ,0x60 ,0x00 ,0x07 ,0xD8 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x05 ,0xA0 ,0x00 ,0x13 ,0xEC ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x04 ,0x20 ,0x00 ,0x29 ,0xF4 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x03 ,0xC0 ,0x00 ,0x64 ,0xF9 ,0x00 ,0x0F ,0xFF ,0x9C ,0x01 ,0xC0 ,0x19 ,0xFF ,0xC0 ,0x7F ,0xFC ,0x7F ,0xF9 ,0xC0 ,0x3D ,0xFF ,0xF1 ,0xFF ,0xE3 ,0xFF ,0xC0 ,0x00 ,0x00 ,0xF2 ,0x73 ,0x80 ,0x0F ,0xFF ,0x9C ,0x01 ,0xC0 ,0x19 ,0xFF ,0xC0 ,0x7F ,0xFE ,0x7F ,0xFD ,0xE0 ,0x3D ,0xFF ,0xF1 ,0xFF ,0xE3 ,0xFF ,0xC0 ,0x00 ,0x00 ,0x79 ,0x26 ,0xC0 ,0x0F ,0xFF ,0xDC ,0x01 ,0xC0 ,0x19 ,0xFF ,0xC0 ,0x7F ,0xFE ,0xFF ,0xFD ,0xF0 ,0x7D ,0xFF ,0xFB ,0xFF ,0xF7 ,0xFF ,0xE0 ,0x00 ,0x03 ,0x3C ,0x8F ,0x60 ,0x0C ,0x01 ,0xDC ,0x01 ,0xC0 ,0x19 ,0x80 ,0x00 ,0x70 ,0x0E ,0xE0 ,0x1D ,0xF0 ,0x7D ,0x80 ,0x3B ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x04 ,0x9E ,0x8F ,0xB0 ,0x0E ,0x01 ,0xDC ,0x01 ,0xC0 ,0x19 ,0x80 ,0x00 ,0x70 ,0x0E ,0xE0 ,0x1D ,0xF8 ,0xFD ,0x80 ,0x33 ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x0E ,0x4F ,0x27 ,0xD8 ,0x0F ,0xFF ,0x9C ,0x01 ,0xC0 ,0x19 ,0xFF ,0xC0 ,0x7F ,0xFC ,0xE0 ,0x1D ,0xF9 ,0xFD ,0xFF ,0xF3 ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x0F ,0x26 ,0x53 ,0xC8 ,0x0F ,0xFF ,0x9C ,0x01 ,0xC0 ,0x19 ,0xFF ,0xC0 ,0x7F ,0xFC ,0xEF ,0xFD ,0xDD ,0xDD ,0xFF ,0xF3 ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x07 ,0x90 ,0xC9 ,0xF0 ,0x0F ,0xFF ,0xDC ,0x01 ,0xC0 ,0x19 ,0xFF ,0xC0 ,0x7F ,0xFE ,0xEF ,0xFD ,0xDF ,0x9D ,0xFF ,0xFB ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x03 ,0xC9 ,0xE4 ,0xE0 ,0x0C ,0x00 ,0xDC ,0x01 ,0xC0 ,0x19 ,0x80 ,0x00 ,0x70 ,0x06 ,0xE7 ,0xFD ,0xCF ,0x9D ,0x80 ,0x3B ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x01 ,0xF0 ,0xF2 ,0x40 ,0x0E ,0x01 ,0xDC ,0x00 ,0xC0 ,0x19 ,0x80 ,0x00 ,0x70 ,0x0E ,0xE0 ,0x1D ,0xCF ,0x1D ,0x80 ,0x3B ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x00 ,0xE6 ,0x79 ,0x00 ,0x0F ,0xFF ,0xDF ,0xFC ,0xFF ,0xF9 ,0xFF ,0xC0 ,0x7F ,0xFE ,0xE0 ,0x1D ,0xC7 ,0x1D ,0xFF ,0xFB ,0xFF ,0xF7 ,0xFF ,0xE0 ,0x00 ,0x00 ,0x49 ,0x3D ,0x00 ,0x0F ,0xFF ,0x9F ,0xFC ,0xFF ,0xF9 ,0xFF ,0xC0 ,0x7F ,0xFE ,0xE0 ,0x1D ,0xC2 ,0x1D ,0xFF ,0xF1 ,0xFF ,0xE3 ,0xFF ,0xC0 ,0x00 ,0x00 ,0x1C ,0x9E ,0x00 ,0x0F ,0xFF ,0x1F ,0xFC ,0x7F ,0xE1 ,0xFF ,0xC0 ,0x7F ,0xFC ,0xE0 ,0x1D ,0xC0 ,0x1D ,0xFF ,0xE0 ,0xFF ,0xC1 ,0xFF ,0x80 ,0x00 ,0x00 ,0x1E ,0x4C ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x0F ,0x20 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x07 ,0x90 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x03 ,0xE0 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x01 ,0xC0 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x80 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 }; //[self addLabel:@"buffer3 is selected"]; [[session outputStream] write:(const uint8_t *)buffer3 maxLength:796];//send print package*/ This is sample code for Image print I am not able to print any other image because I am not having idea how to convert UIImage or NSData to the below mentioned Bit code. If any proper step by step method to do Image to bitmap conversion, then please let me know this.

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  • how to refactor user-permission system?

    - by John
    Sorry for lengthy question. I can't tell if this should be a programming question or a project management question. Any advice will help. I inherited a reasonably large web project (1 year old) from a solo freelancer who architected it then abandoned it. The project was a mess, but I cleaned up what I could, and now the system is more maintainable. I need suggestions on how to extend the user-permission system. As it is now, the database has a t_user table with the column t_user.membership_type. Currently, there are 4 membership types with the following properties: 3 of the membership types are almost functionally the same, except for the different monthly fees each must pay 1 of the membership type is a "fake-user" type which has limited access ( different business logic also applies) With regards to the fake-user type, if you look in the system's business logic files, you will see a lot of hard-coded IF statements that do something like if (fake-user) { // do something } else { // a paid member of type 1,2 or 3 // proceed normally } My client asked me to add 3 more membership types to the system, each of them with unique features to be implemented this month, and substantive "to-be-determined" features next month. My first reaction is that I need to refactor the user-permission system. But it concerns me that I don't have enough information on the "to-be-determined" membership type features for next month. Refactoring the user-permission system will take a substantive amount of time. I don't want to refactor something and throw it out the following month. I get substantive feature requests on a monthly basis that come out of the blue. There is no project road map. I've asked my client to provide me with a roadmap of what they intend to do with the new membership types, but their answer is along the lines of "We just want to do [feature here] this month. We'll think of something new next month." So questions that come to mind are: 1) Is it dangerous for me to refactor the user permission system not knowing what membership type features exist beyond a month from now? 2) Should I refactor the user permission system regardless? Or just continue adding IF statements as needed in all my controller files? Or can you recommend a different approach to user permission systems? Maybe role-based ? 3) Should this project have a road map? For a 1 year old project like mine, how far into the future should this roadmap project? 4) Any general advice on the best way to add 3 new membership types?

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  • Model a Zero or One to Many Relationship

    - by John
    How should I model a zero or one to a many relationship in the database? For example, a user record may or may not have a parent. So should my user table have a t_user.parent_id or should I have an associative table called t_user_hierarchy with the columns t_user_hierarchy.parent_id and t_user_hierarchy.user_id?

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  • Django User "per project" group assignation

    - by Ben G
    Hi, Here's my problem : my site has users, which can create projects, and access other user's projects. Each project can assign different rights to users. So, i could have Project A : user "John" is in group "manager" , and Project "B" user "John" is in group "worker". How could I use the Django User authentication model to do that ? From a SQL point a view, what i would like is to be able to add "project_id" in the primary key for the "auth_user_groups" table. I don't think profile is of any help here. Any advice ? UPDATE : "worker" and "manager" are just two examples of the permission group (or "roles") that my application defines. There will be more in the future. Eg : i will probably also have "admin", "reporting", etc...

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  • Lack of security in many PHP applications?

    - by John
    Over the past year of freelancing, I inherited two web projects, both of them built in PHP, both of them with sensitive information like credit card info, bank info, etc... In one application, when I typed http://thecompany.com/admin/, and without being asked for a username and password, I saw every user's sensitive information, including credit card numbers, bank account numbers etc... In another application, I was able to bypass the login screen by simply typing http://the2ndcompany.com/customer.php?user_id=777, and again, without any prompts for username and password, i was able to see user 777's credit card info. I cycled through a few more user_ids (any integer) and saw each person's credit card info. Is something wrong here? Or is this the quality of work that the "average" programmer produces? Because if this is what the average programmer produces, does that means I'm an...gasp...elite programmer?? No..that can't be right....something doesn't make sense. So my question is, is it just coincidence that I inherited two applications both of which are dangerously lacking in security? Or are there are a lot of bad PHP programmers out there?

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  • Is there a way to morph / convert a circular sprite into a square programmatically?

    - by John
    I have a sprite which is basically just an image of a circle and some content inside. Is there a way that I can programmatically stretch / distort it into something like: I don't care so much about the distortion. The original circular image is 100x100px, and the modified image should also be 100x100px. So its really the content that is being distorted. Can this be done using shaders or some other programmatic way ? The initial circular image is most likely determined at run time, which is why I need to programmatically convert the circular sprite to square. Please do not edit the tags, as the question applies to both versions of cocos2d (iPhone & x), and the solution will most likely work in both regardless of whether one uses C or C++ since the apis are similar, and OpenGL commands work similarly.

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  • fetch only first row from oracle - is it faster?

    - by john
    My main goal with this question is optimization and faster run time. After doing lot of processing in the Stored Proc I finally return a count like below: OPEN cv_1 FOR SELECT COUNT(*) num_of_members FROM HOUSEHOLD_MEMBER a, HOUSEHOLD b WHERE RTRIM(LTRIM(a.mbr_last_name)) LIKE v_MBR_LAST_NAME || '%' AND a.number = '01' AND a.code = v_CODE AND a.ssn_head = v_SSN_HEAD AND TO_CHAR( a.mbr_dob, 'MM/DD/YYYY') = v_DOB; But in my code that is calling the SP does not need the actual count. It just cares that count is greater than 1. Question: How can I change this to return just 1 or 0. 1 when count is 0 and 0 when count 1. Will it be faster to do this rather than returning the whole count?

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  • Ignoring unclosed tags from another <div>?

    - by Mike
    I have a website where members can input text using a limited subset of HTML. When a page is displayed that contains a user's text, if they have any unclosed tags, the formatting "bleeds" across into the next area. For example, if the user entered: Hi, my name is <b>John Then, the rest of the page will be bold. Ideally, there'd be someting I could do that would be this simple: <div contained>Hi, my name is <b>John</div> And no tags could bleed out of that div. Assuming there isn't anything this simple, how would I accomplish a similar effect? Or, is there something this easy? Importantly, I do not want to validate the user's input and return an error if they have unclosed tags, since I want to provide the "easiest" user interface possible for my users. Thanks!

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  • How to package AIR 2 native installer?

    - by John Isaacks
    I have made an AIR 2.0 app that uses NativeProcess so it needs to be packaged as a native installer (.exe) rather than a .air file. I first tried using Package Assistant but I kept getting an error telling me it cannot load keystore file. so I tried using the command line I use: pathToAirSDK>adt -args but I get an error telling me that "adt" is not a known command so I try: pathToAirSDK>adt.jar -args but I get a pop up telling me windows does not know how to open adt.jar files. Has anyone packaged a native installer for an AIR 2.0 app? How did you do it? edit forgot to mention I am doing this in windows using the windows command line.

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  • Deployment of a .NET application making use of SQL Server 2008

    - by Victor John Saliba
    I have searched the internet thoroughly for this type of issue, there were responses but hasn't really found a concrete solution yet. I have an application which makes use of SQL Server 2008 R2 and thus it makes connections with a database file which I have set up. The application executes successfully, makes connections with the database and retrieves/inserts/updates data to and fro the database. However when I come to create a deployment project i.e. a setup project, I fail to transfer my database files to other computers and make database connections. I have checked the SQL Server 2008 prerequisite in the publish settings of the application and has also included the database files. Can anyone suggest the best way to this type of setup? Thanks

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  • Working with EnumSet class in GWT

    - by zenmonkey
    I am having trouble using EnumSet on the client side. I get this runtime error message: java.util.EnumSet.EnumSetImpl is not default instantiable (it must have a zero-argument constructor or no constructors at all) and has no custom serializer. Is this is a known issue? Here is what I am doing (basically a hello world app) Service: String echo (EnumSet<Names> name) throws IllegalArgumentException; Client: echoServ.echo (EnumSet.of(Names.JOHN), new AsyncCallback<String>() { ....... }); Shared enum class enum Names { JOHN, NUMAN, OBAMA }

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  • Emacs How to redefine Shift-R for expected use

    - by John Bellone
    I've checked my elisp files to make sure that I do not have any bindings that contain Shift+R (and I have not found any). I expect SHIFT+R to print an uppercase character, but instead I get R R undefined inside of the Emacs command line. This is only in C/C++ major modes. Any suggestions? Update: Describing the key shows that it is undefined. How would I define it for the normal, expected use (capitalizing the letter R)?

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  • How to process XML sernt via POST?

    - by John Conde
    I'm receiving XML sent via POST. Naturally I need to parse this XML to get at the goodies it holds for me. However, when I receive the XML is seems that PHP is parsing it like a query string. For example, this xml: <?xml version="1.0" encoding="utf-8"?> <ForgotPassword> <version>1.0</version> <authentication> <login>myresllerid</login> <apikey>1234567890abcdef</apikey> </authentication> <parameters> <emailAddress>[email protected]</emailAddress> </parameters> </ForgotPassword> Becomes this (from print_r($_REQUEST)): Array ( [ <?xml_version] => "1.0" encoding="utf-8"?> <IDCForgotPassword> <version>1.0</version> <authentication> <login>myresllerid</login> <apikey>1234567890abcdef</apikey> </authentication> <parameters> <emailAddress>[email protected]</emailAddress> </parameters> </IDCForgotPassword> ) You can see the XML is being broken up at the first equals sign (=) in the XML into a key/value pair. How do I avoid this?

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  • Data model for timesheet to task and/or timesheet to project?

    - by John
    Let's say I want to make a simple project tracking system. A manager can create a project. Then he can create tasks for that project. Team members can record the hours they work for each task or for the project as a whole. Is the following design for the t_timesheet table a good idea? timesheet_id - primary key, autoincrement project_id - not null, foreign key constraint to t_project task_id - nullable, foreign key constraint to t_task user_id - not null, foreign key constraint to t_user hours - decimal Or should I do something like this: timesheet_id - primary key, autoincrement task_id - not null, foreign key constraint to t_task user_id - not null, foreign key constraint to t_user hours - decimal In the second option, I intend to always have a record in t_task labelled "miscellaneous items" with a foreign key to the relevant t_project record. Then I'll be able to track all hours for a project that aren't for any particular task. Are any of the ideas above good? What would be better?

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  • Extract data from PostgreSQL DB without using pg_dump

    - by John Horton
    There is a PostgreSQL database on which I only have limited access (e.g, I can't use pg_dump). I am trying to create a local "mirror" by exporting certain tables from the database. I do not have the permissions needed to just dump a table as SQL from within psql. Right now, I just have a Python script that iterates through my table_names, selects all fields and then exports them as a CSV: for table_name, file_name in zip(table_names, file_names): cmd = """echo "\\\copy (select * from %s)" to stdout WITH CSV HEADER | psql -d remote_db | gzip > ./%s/%s.gz"""%(table_name,dir_name,file_name) os.system(cmd) I would like to not use CSV if possible, as I lose the field types and the encoding can get messed up. First best would probably be some way of getting the generating SQL code for the table using \copy. Next best would be XML, ideally with some way of preserving the field types. If that doesn't work, I think the final option might be two queries---one to get the field data types, the other to get the actual data. Any thoughts or advice would be greatly appreciated - thanks!

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  • How should important terms be emphasized in documentation?

    - by John Rasch
    Software will often introduce and formalize concepts that may have ambiguous definitions in the real world. For example, in an attendance tracking system, an Occurrence refers to an Excused Absence, an Unexcused Absence, or a Tardy. In technical documentation (both in helper text and in user guides, etc), should these concepts be proper nouns, and as such, should they be capitalized in usage? In other words, which of the following examples is more appropriate: After an Occurrence has been created, it may be converted into an Excused Absence once the Approval Form has been uploaded. or After an occurrence has been created, it may be converted into an excused absence once the approval form has been uploaded.

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  • Is there a way to sort by more than one field in Crystal Reports?

    - by John at CashCommons
    I'm using Crystal Report with VB.NET in Visual Studio 2005. I have report that works if I pass in a list of List(Of Stuff). I had been sorting the report by one of the members of Stuff but a need now to sort first by one member, like Stuff.StatusCode and then by another member, like Stuff.ItemNumber. Can I do this just be having more than one SortField member, or do I need to do it some other way? Thanks as always!

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  • Should I use IDisposable for purely managed resources?

    - by John Gietzen
    Here is the scenario: I have an object called a Transaction that needs to make sure that only one entity has permission to edit it at any given time. In order to facilitate a long-lived lock, I have the class generating a token object that can be used to make the edits. You would use it like this: var transaction = new Transaction(); using (var tlock = transaction.Lock()) { transaction.Update(data, tlock); } Now, I want the TransactionLock class to implement IDisposable so that its usage can be clear. But, I don't have any unmanaged resources to dispose. however, the TransctionLock object itself is a sort of "unmanaged resource" in the sense that the CLR doesn't know how to properly finalize it. All of this would be fine and dandy, I would just use IDisposable and be done with it. However, my issue comes when I try to do this in the finalizer: ~TransactionLock() { this.Dispose(false); } I want the finalizer to release the transaction from the lock, if possible. How, in the finalizer, do I detect if the parent transaction (this.transaction) has already been finalized? Is there a better pattern I should be using? The Transaction class looks something like this: public sealed class Transaction { private readonly object lockMutex = new object(); private TransactionLock currentLock; public TransactionLock Lock() { lock (this.lockMutex) { if (this.currentLock != null) throw new InvalidOperationException(/* ... */); this.currentLock = new TransactionLock(this); return this.currentLock; } } public void Update(object data, TransactionLock tlock) { lock (this.lockMutex) { this.ValidateLock(tlock); // ... } } internal void ValidateLock(TransactionLock tlock) { if (this.currentLock == null) throw new InvalidOperationException(/* ... */); if (this.currentLock != tlock) throw new InvalidOperationException(/* ... */); } internal void Unlock(TransactionLock tlock) { lock (this.lockMutex) { this.ValidateLock(tlock); this.currentLock = null; } } }

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  • R: How to pass a list of selection expressions (strings in this case) to the subset function?

    - by John
    Here is some example data: data = data.frame(series = c("1a", "1b", "1e"), reading = c(0.1, 0.4, 0.6)) > data series reading 1 1a 0.1 2 1b 0.4 3 1e 0.6 Which I can pull out selective single rows using subset: > subset (data, series == "1a") series reading 1 1a 0.1 And pull out multiple rows using a logical OR > subset (data, series == "1a" | series == "1e") series reading 1 1a 0.1 3 1e 0.6 But if I have a long list of series expressions, this gets really annoying to input, so I'd prefer to define them in a better way, something like this: series_you_want = c("1a", "1e") (although even this sucks a little) and be able to do something like this, subset (data, series == series_you_want) The above obviously fails, I'm just not sure what the best way to do this is?

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  • Error in my OO Generics design. How do I workaround it?

    - by John
    I get "E2511 Type parameter 'T' must be a class type" on the third class. type TSomeClass=class end; ParentParentClass<T>=class end; ParentClass<T: class> = class(ParentParentClass<T>) end; ChildClass<T: TSomeClass> = class(ParentClass<T>) end; I'm trying to write a lite Generic Array wrapper for any data type(ParentParentClass) ,but because I'm unable to free type idenitifiers( if T is TObject then Tobject(T).Free) , I created the second class, which is useful for class types, so I can free the objects. The third class is where I use my wrapper, but the compiler throws that error. How do I make it compile?

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