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  • Questions on Juval Lowy's IDesign C# Coding Standard

    - by Jan
    We are trying to use the IDesign C# Coding standard. Unfortunately, I found no comprehensive document to explain all the rules that it gives, and also his book does not always help. Here are the open questions that remain for me (from chapter 2, Coding Practices): No. 26: Avoid providing explicit values for enums unless they are integer powers of 2 No. 34: Always explicitly initialize an array of reference types using a for loop No. 50: Avoid events as interface members No. 52: Expose interfaces on class hierarchies No. 73: Do not define method-specific constraints in interfaces No. 74: Do not define constraints in delegates Here's what I think about those: I thought that providing explicit values would be especially useful when adding new enum members at a later point in time. If these members are added between other already existing members, I would provide explicit values to make sure the integer representation of existing members does not change. No idea why I would want to do this. I'd say this totally depends on the logic of my program. I see that there is alternative option of providing "Sink interfaces" (simply providing already all "OnXxxHappened" methods), but what is the reason to prefer one over the other? Unsure what he means here: Could this mean "When implementing an interface explicitly in a non-sealed class, consider providing the implementation in a protected virtual method that can be overridden"? (see Programming .NET Components 2nd Edition, end of chapter “Interfaces and Class Hierarchies”). I suppose this is about providing a "where" clause when using generics, but why is this bad on an interface? I suppose this is about providing a "where" clause when using generics, but why is this bad on a delegate?

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  • Pre-formatting text to prevent reflowing

    - by mattjn
    I've written a fairly simple script that will take elements (in this case, <p> elements are the main concern) and type their contents out like a typewriter, one by one. The problem is that as it types, when it reaches the edge of the container mid-word, it reflows the text and jumps to the next line (like word wrap in any text editor). This is, of course, expected behavior; however, I would like to pre-format the text so that this does not happen. I figure that inserting <br> before the word that will wrap would be the best solution, but I'm not quite sure what the best way to go about doing that is that supports all font sizes and container widths, while also keeping any HTML tags intact. I figure something involving a hidden <span> element, adding text to it gradually and checking its width against the container width might be on the right track, but I'm not quite sure how to actually put this together. Any help or suggestions on better methods would be appreciated.

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  • Database for managing large volumes of (system) metrics

    - by symcbean
    Hi, I'm looking at building a system for managing and reporting stats on web page performance. I'll be collecting a lot more stats than are available in the standard log formats (approx 20 metrics) but compared to most types of database applications, the base data structure will be very simple. My problem is that I'll be accumulating a lot of data - in the region of 100,000 records (i.e. sets of metrics) per hour. Of course, resources are very limited! So that its possible to sensibly interact with the data, I'd need to consolidate each metric into one minute bins, broken down by URL, then for anything more than 1 day old, consolidated into 10 minute bins, then at 1 week, hourly bins. At the front end, I want to provide a view (prefereably as plots) of the last hour of data, with the facility for users to drill up/down through defined hierarchies of URLs (which do not always map directly to the hierarchy expressed in the path of the URL) and to view different time frames. Rather than coding all this myself and using a relational database, I was wondering if there were tools available which would facilitate both the management of the data and the reporting. I had a look at Mondrian however I can't see from the documentation I've looked at whether it's possible to drop the more granular information while maintaining the consolidated views of the data. RRDTool looks promising in terms of managing the data consolidation, but seems to be rather limited in terms of querying the dataset as a multi-dimensional/relational database. What else whould I be looking at?

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  • Are there Windows API binaries for Subversion or do I have to build SVN to call the API from Windows

    - by JeffH
    I want to call a Subversion API from a Visual Studio 2003 C++ project. I know there are threads here, here, here, and here that tell how to get started with C#.NET on Windows (the consensus seems to be SharpSvn, which I've used easily and successfully on another project) but that's not what I want. I've read the chapter on using APIs in the red-bean book which says: Subversion is primarily a set of C libraries, with header (.h) files that live in the subversion/include directory of the source tree. These headers are copied into your system locations (e.g., /usr/local/include) when you build and install Subversion itself from source. These headers represent the entirety of the functions and types meant to be accessible by users of the Subversion libraries. I'd like to use CollabNet Subversion but there doesn't seem to be API binary downloads, and I'd just as soon not build the whole thing if I can avoid it. Considering another approach, I found RapidSVN's C++ API, but it doesn't appear to offer Windows API binaries either and seems to require building SVN (which I would be willing to do as a last choice if RapidSVN's API is higher-level than the stock SVN offering.) Does calling the API from C++ in Windows have to be this much more work compared to using SharpSvn under .NET, or is there something I haven't found that would help me achieve my goal?

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  • Javascript cloned object looses its prototype functions

    - by Jake M
    I am attempting to clone an object in Javascript. I have made my own 'class' that has prototype functions. My Problem: When I clone an object, the clone cant access/call any prototype functions. I get an error when I go to access a prototype function of the clone: clone.render is not a function Can you tell me how I can clone an object and keep its prototype functions This simple JSFiddle demonstrates the error I get: http://jsfiddle.net/VHEFb/1/ function cloneObject(obj) { // Handle the 3 simple types, and null or undefined if (null == obj || "object" != typeof obj) return obj; // Handle Date if (obj instanceof Date) { var copy = new Date(); copy.setTime(obj.getTime()); return copy; } // Handle Array if (obj instanceof Array) { var copy = []; for (var i = 0, len = obj.length; i < len; ++i) { copy[i] = cloneObject(obj[i]); } return copy; } // Handle Object if (obj instanceof Object) { var copy = {}; for (var attr in obj) { if (obj.hasOwnProperty(attr)) copy[attr] = cloneObject(obj[attr]); } return copy; } throw new Error("Unable to copy obj! Its type isn't supported."); } function MyObject(name) { this.name = name; // I have arrays stored in this object also so a simple cloneNode(true) call wont copy those // thus the need for the function cloneObject(); } MyObject.prototype.render = function() { alert("Render executing: "+this.name); } var base = new MyObject("base"); var clone = cloneObject(base); clone.name = "clone"; base.render(); clone.render(); // Error here: "clone.render is not a function"

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  • Problem with incomplete input when using Attoparsec

    - by Dan Dyer
    I am converting some functioning Haskell code that uses Parsec to instead use Attoparsec in the hope of getting better performance. I have made the changes and everything compiles but my parser does not work correctly. I am parsing a file that consists of various record types, one per line. Each of my individual functions for parsing a record or comment works correctly but when I try to write a function to compile a sequence of records the parser always returns a partial result because it is expecting more input. These are the two main variations that I've tried. Both have the same problem. items :: Parser [Item] items = sepBy (comment <|> recordType1 <|> recordType2) endOfLine For this second one I changed the record/comment parsers to consume the end-of-line characters. items :: Parser [Item] items = manyTill (comment <|> recordType1 <|> recordType2) endOfInput Is there anything wrong with my approach? Is there some other way to achieve what I am attempting?

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  • Reserve space for initially hidden widget in QVBoxLayout

    - by Skinniest Man
    I am using a QVBoxLayout to arrange a vertical stack of widgets. I want some of them to be initially hidden and only show up when a check box is checked. Here is an example of the code I'm using. MyWidget::MyWidget(QWidget *parent) : QWidget(parent) { QVBoxLayout *layout = new QVBoxLayout(this); QLabel *labelLogTypes = new QLabel(tr("Log Types")); m_checkBoxCsv = new QCheckBox(tr("&Delimited File (CSV)")); m_labelDelimiter = new QLabel(tr("Delimiter:")); m_lineEditDelimiter = new QLineEdit(","); checkBoxCsv_Toggled(m_checkBoxCsv-isChecked()); connect(m_checkBoxCsv, SIGNAL(toggled(bool)), SLOT(checkBoxCsv_Toggled(bool))); QHBoxLayout *layoutDelimitedChar = new QHBoxLayout(); layoutDelimitedChar-addWidget(m_labelDelimiter); layoutDelimitedChar-addWidget(m_lineEditDelimiter); m_checkBoxXml = new QCheckBox(tr("&XML File")); m_checkBoxText = new QCheckBox(tr("Plain &Text File")); // Now that everything is constructed, put it all together // in the main layout. layout-addWidget(labelLogTypes); layout-addWidget(m_checkBoxCsv); layout-addLayout(layoutDelimitedChar); layout-addWidget(m_checkBoxXml); layout-addWidget(m_checkBoxText); layout-addStretch(); } MyWidget::checkBoxCsv_Toggled(bool checked) { m_labelDelimiter-setVisible(checked); m_lineEditDelimiter-setVisible(checked); } I want m_labelDelimiter and m_lineEditDelimiter both to be initially invisible and I want their visibility to toggle with the state of m_checkBoxCsv. This code acheives the functionality I desire, but it doesn't seem to reserve space for the two initially hidden widgets. When I check the checkbox, they become visible, but everything is kind of scrunched to accomodate them. If I leave them initially visible, everything is laid out just the way I would like it. Is there any way to make the QVBoxLayout reserve space for these widgets even if they're initially invisible?

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  • [nHibernate] casting string to bool using nHibernate Criteria

    - by code-zoop
    I have an nHibernate query using Criteria, and I am trying to cast a string to bool in the query itself. I have done the same with casting a string to int, and that works well (the "DataField" property is "1" as a string): var result = Session .CreateCriteria<Car>() .Add(Restrictions.Eq((Projections.Cast(NHibernateUtil.Int32, Projections.Property("DataField"), 1)) .List<Car>(); tx.Commit(); But I am trying to do the same with bool, but I do not get the expected result: var result = Session .CreateCriteria<Car>() .Add(Restrictions.Eq((Projections.Cast(NHibernateUtil.bool, Projections.Property("DataField"), true)) .List<Car>(); tx.Commit(); "DataField" is the string "True", but the result in an empty list, where it should contain 100 elements with the "DataField" property string set to "True". I have tried with the string "true", and "1", but the result is still an empty List. [EDIT] As Commented below, I could check for the string "True" or "False", but I would say this is a more general question than just for the Boolean. Note that the idea is to have some sort of key value representation of the data, where the value can be different data types. I need the value table to contain all data, so storing the data as string seems like the cleanest solution! I have been able to use the method above to store both int and double as string, and to the cast in the query, but I have not succeeded using the same method for DateDime and Boolean. And for DateTime it is crucial to have the actual DateTime object. How can I make the cast from string to bool, and string to DateTime work in the queries? Thanks

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  • create a class attribute without going through __setattr__

    - by eric.frederich
    Hello, What I have below is a class I made to easily store a bunch of data as attributes. They wind up getting stored in a dictionary. I override __getattr__ and __setattr__ to store and retrieve the values back in different types of units. When I started overriding __setattr__ I was having trouble creating that initial dicionary in the 2nd line of __init__ like so... super(MyDataFile, self).__setattr__('_data', {}) My question... Is there an easier way to create a class level attribute with going through __setattr__? Also, should I be concerned about keeping a separate dictionary or should I just store everything in self.__dict__? #!/usr/bin/env python from unitconverter import convert import re special_attribute_re = re.compile(r'(.+)__(.+)') class MyDataFile(object): def __init__(self, *args, **kwargs): super(MyDataFile, self).__init__(*args, **kwargs) super(MyDataFile, self).__setattr__('_data', {}) # # For attribute type access # def __setattr__(self, name, value): self._data[name] = value def __getattr__(self, name): if name in self._data: return self._data[name] match = special_attribute_re.match(name) if match: varname, units = match.groups() if varname in self._data: return self.getvaras(varname, units) raise AttributeError # # other methods # def getvaras(self, name, units): from_val, from_units = self._data[name] if from_units == units: return from_val return convert(from_val, from_units, units), units def __str__(self): return str(self._data) d = MyDataFile() print d # set like a dictionary or an attribute d.XYZ = 12.34, 'in' d.ABC = 76.54, 'ft' # get it back like a dictionary or an attribute print d.XYZ print d.ABC # get conversions using getvaras or using a specially formed attribute print d.getvaras('ABC', 'cm') print d.XYZ__mm

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  • C: socket connection timeout

    - by The.Anti.9
    I have a simple program to check if a port is open, but I want to shorten the timeout length on the socket connection because the default is far too long. I'm not sure how to do this though. Here's the code: #include <sys/socket.h> #include <sys/time.h> #include <sys/types.h> #include <arpa/inet.h> #include <netinet/in.h> #include <errno.h> #include <fcntl.h> #include <stdio.h> #include <netdb.h> #include <stdlib.h> #include <string.h> #include <unistd.h> int main(int argc, char **argv) { u_short port; /* user specified port number */ char addr[1023]; /* will be a copy of the address entered by u */ struct sockaddr_in address; /* the libc network address data structure */ short int sock = -1; /* file descriptor for the network socket */ if (argc != 3) { fprintf(stderr, "Usage %s <port_num> <address>", argv[0]); return EXIT_FAILURE; } address.sin_addr.s_addr = inet_addr(argv[2]); /* assign the address */ address.sin_port = htons(atoi(argv[2])); /* translate int2port num */ sock = socket(AF_INET, SOCK_STREAM, 0); if (connect(sock,(struct sockaddr *)&address,sizeof(address)) == 0) { printf("%i is open\n", port); } close(sock); return 0; }

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  • How to work with CTE. There is some error related to anchor.

    - by Shantanu Gupta
    I am creating a hierarchy representaion of a column. But an error occurs Details are Msg 240, Level 16, State 1, Line 1 Types don't match between the anchor and the recursive part in column "DISPLAY" of recursive query "CTE". I know there is some typecasting error. But I dont know how to remove error. Please just dont only sort out my error. I need explanation why this error is coming. When this error occurs. I am trying to sort table on the basis of sort col that i m introducing. I want to add '-' at every level and want to sort accordingly. Please help WITH CTE (PK_CATEGORY_ID, [DESCRIPTION], FK_CATEGORY_ID, DISPLAY, SORT, DEPTH) AS ( SELECT PK_CATEGORY_ID, [DESCRIPTION], FK_CATEGORY_ID, '-' AS DISPLAY, '--' AS SORT, 0 AS DEPTH FROM dbo.L_CATEGORY_TYPE WHERE FK_CATEGORY_ID IS NULL UNION ALL SELECT T.PK_CATEGORY_ID, T.[DESCRIPTION], T.FK_CATEGORY_ID, CAST(DISPLAY+T.[DESCRIPTION] AS VARCHAR(1000)), '--' AS SORT, C.DEPTH +1 FROM dbo.L_CATEGORY_TYPE T JOIN CTE C ON C.PK_CATEGORY_ID = T.FK_CATEGORY_ID --SELECT T.PK_CATEGORY_ID, C.SORT+T.[DESCRIPTION], T.FK_CATEGORY_ID --, CAST('--' + C.SORT AS VARCHAR(1000)) AS SORT, CAST(DEPTH +1 AS INT) AS DEPTH --FROM dbo.L_CATEGORY_TYPE T JOIN CTE C ON C.FK_CATEGORY_ID = T.PK_CATEGORY_ID ) SELECT PK_CATEGORY_ID, [DESCRIPTION], FK_CATEGORY_ID, DISPLAY, SORT, DEPTH FROM CTE ORDER BY SORT

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  • ant conditions problem

    - by senzacionale
    I have problem with ant. I woul dlike to use conditions in ant. But i get error of: BUILD FAILED C:\Projekti\Projekt ANT\build.xml:412: Problem: failed to create task or type Cause: The name is undefined. Action: Check the spelling. Action: Check that any custom tasks/types have been declared. Action: Check that any / declarations have taken place. and this is code: <target name="test"> <input message="Write some text: " addproperty="foo" /> <if> <equals arg1="${foo}" arg2="bar" /> <then> <echo message="The value of property foo is 'bar'" /> </then> <elseif> <equals arg1="${foo}" arg2="foo" /> <then> <echo message="The value of property foo is 'foo'" /> </then> </elseif> <else> <echo message="The value of property foo is not 'foo' or 'bar'" /> </else> </if> </target>

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  • Why can't I extract a C++ type from a Python type using boost::python::extractor?

    - by Robin
    I've wrapped a C++ class using Py++ and everything is working great in Python. I can instantiate the c++ class, call methods, etc. I'm now trying to embed some Python into a C++ application. This is also working fine for the most-part. I can call functions on a Python module, get return values, etc. The python code I'm calling returns one of the classes that I wrapped: import _myextension as myext def run_script(arg): my_cpp_class = myext.MyClass() return my_cpp_class I'm calling this function from C++ like this: // ... excluding error checking, ref counting, etc. for brevity ... PyObject *pModule, *pFunc, *pArgs, *pReturnValue; Py_Initialize(); pModule = PyImport_Import(PyString_FromString("cpp_interface")); pFunc = PyObject_GetAttrString(pModule, "run_script"); pArgs = PyTuple_New(1); PyTuple_SetItem(pArgs, 0, PyString_FromString("an arg")); pReturnValue = PyObject_CallObject(pFunc, pArgs); bp::extract< MyClass& > extractor(pReturnValue); // PROBLEM IS HERE if (extractor.check()) { // This check is always false MyClass& cls = extractor(); } The problem is the extractor never actually extracts/converts the PyObject* to MyClass (i.e. extractor.check() is always false). According to the docs this is the correct way to extract a wrapped C++ class. I've tried returning basic data types (ints/floats/dicts) from the Python function and all of them are extracted properly. Is there something I'm missing? Is there another way to get the data and cast to MyClass?

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  • Java: Typecasting to Generics

    - by bguiz
    This method that uses method-level generics, that parses the values from a custom POJO, JXlistOfKeyValuePairs (which is exactly that). The only thing is that both the keys and values in JXlistOfKeyValuePairs are Strings. This method wants to taken in, in addition to the JXlistOfKeyValuePairs instance, a Class<T> that defines which data type to convert the values to (assume that only Boolean, Integer and Float are possible). It then outputs a HashMap with the specified type for the values in its entries. This is the code that I have got, and it is obviously broken. private <T extends Object> Map<String, T> fromListOfKeyValuePairs(JXlistOfKeyValuePairs jxval, Class<T> clasz) { Map<String, T> val = new HashMap<String, T>(); List<Entry> jxents = jxval.getEntry(); T value; String str; for (Entry jxent : jxents) { str = jxent.getValue(); value = null; if (clasz.isAssignableFrom(Boolean.class)) { value = (T)(Boolean.parseBoolean(str)); } else if (clasz.isAssignableFrom(Integer.class)) { value = (T)(Integer.parseInt(str)); } else if (clasz.isAssignableFrom(Float.class)) { value = (T)(Float.parseFloat(str)); } else { logger.warn("Unsupported value type encountered in key-value pairs, continuing anyway: " + clasz.getName()); } val.put(jxent.getKey(), value); } return val; } This is the bit that I want to solve: if (clasz.isAssignableFrom(Boolean.class)) { value = (T)(Boolean.parseBoolean(str)); } else if (clasz.isAssignableFrom(Integer.class)) { value = (T)(Integer.parseInt(str)); } I get: Inconvertible types required: T found: Boolean Also, if possible, I would like to be able to do this with more elegant code, avoiding Class#isAssignableFrom. Any suggestions? Sample method invocation: Map<String, Boolean> foo = fromListOfKeyValuePairs(bar, Boolean.class);

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  • MS Exam 70-536 - How to throw and handle exception from thread?

    - by Max Gontar
    Hello! In MS Exam 70-536 .Net Foundation, Chapter 7 "Threading" in Lesson 1 Creating Threads there is a text: Be aware that because the WorkWithParameter method takes an object, Thread.Start could be called with any object instead of the string it expects. Being careful in choosing your starting method for a thread to deal with unknown types is crucial to good threading code. Instead of blindly casting the method parameter into our string, it is a better practice to test the type of the object, as shown in the following example: ' VB Dim info As String = o as String If info Is Nothing Then Throw InvalidProgramException("Parameter for thread must be a string") End If // C# string info = o as string; if (info == null) { throw InvalidProgramException("Parameter for thread must be a string"); } So, I've tried this but exception is not handled properly (no console exception entry, program is terminated), what is wrong with my code (below)? class Program { static void Main(string[] args) { Thread thread = new Thread(SomeWork); try { thread.Start(null); thread.Join(); } catch (InvalidProgramException ex) { Console.WriteLine(ex.Message); } finally { Console.ReadKey(); } } private static void SomeWork(Object o) { String value = (String)o; if (value == null) { throw new InvalidProgramException("Parameter for "+ "thread must be a string"); } } } Thanks for your time!

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  • Multiple "ObjectChangeTracker" getting created, can it be avoided?

    - by user555937
    Hi, We are working on a POC where we have following architecture (MVVM), WPF(Client) + WCF + Model(DataAccess)+ ADO.Net Entity Framework 4.0 (with SQL Server 2008 R2 as DB) All are different projects. In the DataAccess layer we have created different Entity Models(edmx) based on the functionality. The tables under perticular flow are grouped and created different entity models. We are using self tracking entities to and fro to communicate with the WPF client through wcf service. For Single model everything works fine. But when we created a Multiple models then few issues started coming. Mutliple models have few duplicate tables/entities. Two probels are, 1) When we try to access entities from different models mutiple objects "ObjectChangeTracker" are getting created. E.g. CompanyModel(edmx) - Company(Entity) - ObjectChangeTracker, ObjectState ProductModel(edmx) - Customer(Entity) - ObjectChangeTracker1, ObjectState1 OrderModel(edmx) - Oder(Entity) - ObjectChangeTracker2, ObjectState2 Is there any way to avoid this? 2) There are few tables which shared across the Models, E.g. Company(Entity) is used in All above mdoels. During compile time it does not thow any error. But run time It gives error saying "Schema specified is not valid. Errors: The mapping of CLR type to EDM type is ambiguous because multiple CLR types match the EDM type "Company"".. To resolve this, we renamed the entities with some prefix to make them Unique. Is there any other way we can resolve this without changing the name of the entity in the same assembly? Thanks in advance and appreciate if anyone has approach for these issues. Thanks, Kiran

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  • OpenGL ES and real world development

    - by Mark
    Hi Guys, I'm trying to learn OpenGL ES quickly (I know, I know, but these are the pressures that have been thrusted upon me) and I have been read around a fair bit, which lots of success at rendering basic models, some basic lighting and 'some' texturing success too. But this is CONSTANTLY the point at which all OpenGL ES tutorials end, they never say more of what a real life app may need. So I have a few questions that Im hoping arent too difficult. How do people get 3d models from their favorite 3d modeling tool into the iPhone/iPad application? I have seen a couple of blog posts where people have written some python scripts for tools like Blender which create .h files that you can use, is this what people seem to do everytime? Or do the "big" tooling suites (3DS, Maya, etc...) have exporting features? Say I have my model in a nice .h file, all the vertexes, texture points, etc.. are lined up, how to I make my model (say of a basic person) walk? Or to be more general, how do you animate "part" of a model (legs only, turn head, etc...)? Do they need to be a massive mash-up of many different tiny models, or can you pre-bake animations these days "into" models (somehow) Truely great 3D games for the iPhone are (im sure) unbelievably complex, but how do people (game dev firms) seem to manage that designer/developer workflow? Surely not all the animations, textures, etc... are done programatically. I hope these are not stupid questions, and in actual fact, my app that Im trying to investigate how to make is really quite simple, just a basic 3D model that I want to be able to pan/tilt around using touch. Has anyone ever done/seen anything like this that I might be able to read up on? Thanks for any help you can give, I appreciate all types of response big or small :) Cheers, Mark

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  • MMGR Questions, code use and thread-saftey

    - by chadb
    1) Is MMGR thread safe? 2) I was hoping someone could help me understand some code. I am looking at something where a macro is used, but I don't understand the macro. I know it contains a function call and an if check, however, the function is a void function. How does wrapping "(m_setOwner (FILE,_LINE_,FUNCTION),false)" ever change return types? #define someMacro (m_setOwner(__FILE__,__LINE__,__FUNCTION__),false) ? NULL : new ... void m_setOwner(const char *file, const unsigned int line, const char *func); 3) What is the point of the reservoir? 4) On line 770 ("void *operator new(size_t reportedSize)" there is the line "// ANSI says: allocation requests of 0 bytes will still return a valid value" Who/what is ANSI in this context? Do they mean the standards? 5) This is more of C++ standards, but where does "reportedSize" come from for "void *operator new(size_t reportedSize)"? 6) Is this the code that is actually doing the allocation needed? "au-actualAddress = malloc(au-actualSize);"

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  • C# Type conversion between two similar Datatable objects

    - by Ali
    I have .NET project with sync framework and two separate Datasets for MS SQL and Compact SQL. in my base class I have a generic DataTable object. in my derived classed I assign Typed DataTable to the generic object based on whether the application is operating online or offline: example: if (online) _dataTable = new MSSQLDataSet.Customer; else _dataTable = new CompactSQLDataSet.Customer; Now every where in my code i have to check and do a cast based on the current network mode like this: public void changeCustomerID(int ID) { if (online) (MSSQLDataSet.CustomerDataTable)_dataTable)[i].CustomerID = value; else (CompactMSSQLDataSet.CustomerDataTable)_dataTable)[i].CustomerID = value; } but I don't think this is very efficient and I believe it can be done in a smarter way to only use one line of code by dynamically getting the Type of _dataTable on the run time. my problem is at the design time, in order to acess datatable porperties such as "CustomerID" it has to be casted to either MSSQLDataSet.CustomerDataTable or CompactMSSQLDataSet.CustomerDataTable. Is there a way to have a function or a operator to convert the _datatable to its runtime type but still be able to use it's design time properties which are the same between the two types? something like: ((aType)_dataTable)[i].CustomerID = value; //or GetRuntimeType(_dataTable)[i].CustomerID = value;

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  • MySQL - What is wrong with this query or my database? Terrible performance.

    - by Moss
    SELECT * from `employees` a LEFT JOIN (SELECT phone1 p1, count(*) c, FROM `employees` GROUP BY phone1) b ON a.phone1 = b.p1; I'm not sure if it is this query in particular that has the problem. I have been getting terrible performance in general with this database. The table in question has 120,000 rows. I have tried this particular query remotely and locally with the MyISAM and InnoDB engines, with different types of joins, and with and without an index on phone1. I can get this to complete in about 4 minutes on a 10,000 row table successfully but performance drops exponentially with larger tables. Remotely it will lose connection to the server and locally it brings my system to its knees and seems to go on forever. This query is only a smaller step I was trying to do when a larger query couldn't complete. Maybe I should explain the whole scenario. I have one big flat ugly table that lists a bunch of people and their contact info and the info of the companies they work for. I'm trying to normalize the database and intelligently determine which phone numbers apply to individual people and which apply to an office location. My reasoning is that if a phone number occurs multiple times and the number of occurrence equals the number of times that the street address it is attached to occurs then it must be an office number. So the first step is to count each phone number grouping by phone number. Normally if you just use COUNT()...GROUP BY it will only list the first record it finds in that group so I figured I have to join the full table to the count table where the phone number matches. This does work but as I said I can't successfully complete it on any table much larger than 10,000 rows. This seems pathetic and this doesn't seem like a crazy query to do. Is there a better way to achieve what I want or do I have to break my large table into 12 pieces or is there something wrong with the table or db?

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  • Starting an STA thread, but with parameters to the final function

    - by DRapp
    I'm a bit weak on how some delegates behave, such as passing a method as the parameter to be invoked. While trying to do some NUnit test scripts, I have something that I need to run many test with. Each of these tests requires a GUI created and thus the need for an STA thread. So, I have something like public class MyTest { // the Delegate "ThreadStart" is part of the System.Threading namespace and is defined as // public delegate void ThreadStart(); protected void Start_STA_Thread(ThreadStart whichMethod) { Thread thread = new Thread(whichMethod); thread.SetApartmentState(ApartmentState.STA); //Set the thread to STA thread.Start(); thread.Join(); } [Test] public void Test101() { // Since the thread issues an INVOKE of a method, I'm having it call the // corresponding "FromSTAThread" method, such as Start_STA_Thread( Test101FromSTAThread ); } protected void Test101FromSTAThread() { MySTA_RequiredClass oTmp = new MySTA_RequiredClass(); Assert.IsTrue( oTmp.DoSomething() ); } } This part all works fine... Now the next step. I now have a different set of tests that ALSO require an STA thread. However, each "thing" I need to do requires two parameters... both strings (for this case). How do I go about declaring proper delegate so I can pass in the method I need to invoke, AND the two string parameters in one shot... I may have 20+ tests to run with in this pattern and may have future of other similar tests with different parameter counts and types of parameters too. Thanks.

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  • IPad SQLite Push and Pull Data from external MS SQL Server DB

    - by MattyD
    This carries on from my previous post (http://stackoverflow.com/questions/4182664/ipad-app-pull-and-push-relational-data). My plan is that when the ipad application starts I am going to pull data (config data i.e. Departments, Types etc etc relational data that is used across the system) from a webhosted MS SQL Server DB via a webservice and populate it into an SQL Lite DB on the IPad. Then when I load a listing I will pull the data over the line again via a webservice and populate it into the SQL Lite db on the ipad (than just run select commands to populate the listing). My questions are: 1. What is the most efficient way to transfer data across the line via the web? Everyone seems to do it a different way. My idea is that I will have a webService for each type of data pull (e.g. RetrieveContactListing) that will query the db and than convert that data into "something" to send across the line. My question really is what is the "something" that it should be converting into? 2. Everyone talks about odata services. Is this suited for applications where complex read and writes are needed? Ive created a simple iphone app before that talked to an sql server db (i just sent my own structured xml across the line) but now with this app the data calls are going to be a lot larger so efficiency is key.

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  • Java: using generic wildcards with subclassing

    - by gibberish
    Say I have a class Foo, a class A and some subclass B of A. Foo accepts A and its sublclasses as the generic type. A and B both require a Foo instance in their constructor. I want A's Foo to be of type A , and B's Foo to be of type B or a superclass of B. So in effect, So I only want this: Foo<X> bar = new Foo<X>; new B(bar); to be possible if X is either A, B, or a both subclass of A and superclass of B. So far this is what I have: class Foo<? extends A>{ //construct } class A(Foo<A> bar){ //construct } class B(Foo<? super B> bar){ super(bar); //construct } The call to super(...) doesn't work, because <A> is stricter than <? super B>. Is it somehow possible to use the constructor (or avoid code duplication by another means) while enforcing these types? Edit: Foo keeps a collection of elements of the generic parameter type, and these elements and Foo have a bidirectional link. It should therefore not be possible to link an A to a Foo.

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  • Java string to double conversion.

    - by wretrOvian
    Hi, I've been reading up on the net about the issues with handling float and double types in java. Unfortunately, the image is still not clear. Hence, i'm asking here direct. :( My MySQL table has various DECIMAL(m,d) columns. The m may range from 5 to 30. d stays a constant at 2. Question 1. What equivalent data-type should i be using in Java to work (i.e store, retrieve, and process) with the size of the values in my table? (I've settled with double - hence this post). Question 2. While trying to parse a double from a string, i'm getting errors Double dpu = new Double(dpuField.getText()); for example - "1" -> java.lang.NumberFormatException: empty String "10" -> 1.0 "101" -> 10.0 "101." -> 101.0 "101.1" -> 101.0 "101.19" -> 101.1 What am i doing wrong? What is the correct way to convert a string to a double value? And what measures should i take to perform operations on such values?

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  • Java/JAXB: Accessing property of object in a list

    - by Mark Lewis
    Hello Using JAXB I've created a series of classes which represent my XML schema. Validating against the schema an XML file has thus become a 'tree' of java objects representing the XML. Now I'd like to access, delete and add an object of one the created types in my tree. If I've got classes' methods arranged like this: RootType class has: public List<FQType> getFq() { // and setter return fq; } FQType class has: public RemapType getRemap() { // and setter return remap; } RemapType class has: public String getSource() { // and setter return source; } What's the most concise way to code reading and writing of the 'source' member of a RemapType instance in an FQType instance with, say, fqtypeID=1, in an array of type RootType (in which RootType instances also each have rootID)? Currently I'm using a for loop Iterator in which is an if rootID = mySelectedRootID. In the if I nest a second for loop Iterator over the contained FQType instances and in that a second if fqTypeID = mySelectedFQTypeID. IE for loop iterator/if statement pairs to recognise the object of desire. With all the bells and whistles this way is nearly 15 lines of code to access a data type - can I do this in one line? Thanks

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