Search Results

Search found 2498 results on 100 pages for 'unary operator'.

Page 89/100 | < Previous Page | 85 86 87 88 89 90 91 92 93 94 95 96  | Next Page >

  • 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;

    Read the article

  • Implicit Type Conversions in Reflection

    - by bradhe
    So I've written a quick bit of code to help quickly convert between business objects and view models. Not to pimp my own blog, but you can find the details here if you're interested or need to know. One issue I've run in to is that I have a custom collection type, ProductCollection, and I need to turn that in to a string[] in on my model. Obviously, since there is no default implicit cast, I'm getting an exception in my contract converter. So, I thought I would write the next little bit of code and that should solve the problem: public static implicit operator string[](ProductCollection collection) { var list = new List<string>(); foreach (var product in collection) { if (product.Id == null) { list.Add(null); } else { list.Add(product.Id.ToString()); } } return list.ToArray(); } However, it still fails with the same cast exception. I'm wondering if it has something to do with being in reflection? If so, is there anything that I can do here?? I'm open to architectural solutions, too!

    Read the article

  • How can click on a java show link programatically?

    - by Jules
    I'm trying to develop a new feature for our vb.net order entry system. At the moment I provide an assisted paypal login which loops through transactions and copies the transactions. My program then looks at this data and copies it into text boxes. The operator then approves and saves the record. So my code uses IHTMLFormElement and loops round form elements and adds values. However I only really use this to log in to paypal. See my code... Dim theObject As Object = Nothing theObject = "https://www.paypal.com/cgi-bin/webscr?cmd=_login-run" WebBrowPayPal.AxWebBrowser1.Navigate2(theObject) While WebBrowPayPal.AxWebBrowser1.ReadyState <> tagREADYSTATE.READYSTATE_COMPLETE Application.DoEvents() End While Dim HtmlDoc As IHTMLDocument2 = CType(WebBrowPayPal.AxWebBrowser1.Document, IHTMLDocument2) Dim FormCol As IHTMLElementCollection = HtmlDoc.forms Dim iForms As Integer = FormCol.length Dim i As Integer Dim x As Integer For i = 0 To iForms - 1 Dim oForm As IHTMLFormElement = CType(FormCol.item(CType(i, Object), CType(i, Object)), IHTMLFormElement) For x = 0 To oForm.length - 1 If oForm.elements(x).tagname = "INPUT" Then If oForm.elements(x).name = "login_email" Then oForm.elements(x).value = "[email protected]" End If If oForm.elements(x).name = "login_password" Then oForm.elements(x).value = "mypassword" End If If oForm.elements(x).type = "submit" Or _ oForm.elements(x).type = "SUBMIT" Then oForm.elements(x).click() End If End If Next Next i I'm now trying this page https://www.paypal.com/uk/cgi-bin/webscr?cmd=_history&nav=0.3.0 Which is the history page, which allows you to search on the paypal transaction id. Unfortunately you need to click on 'find a transaction' which then uses some javascript to shows the post fields. So the problem is that the fields I need to use are hidden. How can I click on this java link in code ?

    Read the article

  • Linq2Sql: query - subquery optimisation

    - by Budda
    I have the following query: IList<InfrStadium> stadiums = (from sector in DbContext.sectors where sector.Type=typeValue select new InfrStadium(sector.TeamId) ).ToList(); and InfrStadium class constructor: private InfrStadium(int teamId) { IList<Sector> teamSectors = (from sector in DbContext.sectors where sector.TeamId==teamId select sector) .ToList<>(); ... work with data } Current implementation perform 1+n queries, where n - number of records fetched the 1st time. I want to optimize that. And another one I would love to do using 'group' operator in way like this: IList<InfrStadium> stadiums = (from sector in DbContext.sectors group sector by sector.TeamId into team_sectors select new InfrStadium(team_sectors.Key, team_sectors) ).ToList(); with appropriate constructor: private InfrStadium(int iTeamId, IEnumerable<InfrStadiumSector> eSectors) { IList<Sector> teamSectors = eSectors.ToList(); ... work with data } But attempt to launch query causes the following error: Expression of type 'System.Int32' cannot be used for constructor parameter of type 'System.Collections.Generic.IEnumerable`1[InfrStadiumSector]' Question 1: Could you please explain, what is wrong here, I don't understand why 'team_sectors' is applied as 'System.Int32'? I've tried to change query a little (replace IEnumerable with IQueryeable): IList<InfrStadium> stadiums = (from sector in DbContext.sectors group sector by sector.TeamId into team_sectors select new InfrStadium(team_sectors.Key, team_sectors.AsQueryable()) ).ToList(); with appropriate constructor: private InfrStadium(int iTeamId, IQueryeable<InfrStadiumSector> eSectors) { IList<Sector> teamSectors = eSectors.ToList(); ... work with data } In this case I've received another but similar error: Expression of type 'System.Int32' cannot be used for parameter of type 'System.Collections.Generic.IEnumerable1[InfrStadiumSector]' of method 'System.Linq.IQueryable1[InfrStadiumSector] AsQueryableInfrStadiumSector' Question 2: Actually, the same question: can't understand at all what is going on here... P.S. I have another to optimize query idea (describe here: Linq2Sql: query optimisation) but I would love to find a solution with 1 request to DB).

    Read the article

  • How do I send floats in window messages.

    - by yngvedh
    Hi, What is the best way to send a float in a windows message using c++ casting operators? The reason I ask is that the approach which first occurred to me did not work. For the record I'm using the standard win32 function to send messages: PostWindowMessage(UINT nMsg, WPARAM wParam, LPARAM lParam) What does not work: Using static_cast<WPARAM>() does not work since WPARAM is typedef'ed to UINT_PTR and will do a numeric conversion from float to int, effectively truncating the value of the float. Using reinterpret_cast<WPARAM>() does not work since it is meant for use with pointers and fails with a compilation error. I can think of two workarounds at the moment: Using reinterpret_cast in conjunction with the address of operator: float f = 42.0f; ::PostWindowMessage(WM_SOME_MESSAGE, *reinterpret_cast<WPARAM*>(&f), 0); Using an union: union { WPARAM wParam, float f }; f = 42.0f; ::PostWindowMessage(WM_SOME_MESSAGE, wParam, 0); Which of these are preffered? Are there any other more elegant way of accomplishing this?

    Read the article

  • Javascript Getting Objects to Fallback to One Another

    - by Ian
    Here's a ugly bit of Javascript it would be nice to find a workaround. Javascript has no classes, and that is a good thing. But it implements fallback between objects in a rather ugly way. The foundational construct should be to have one object that, when a property fails to be found, it falls back to another object. So if we want a to fall back to b we would want to do something like: a = {sun:1}; b = {dock:2}; a.__fallback__ = b; then a.dock == 2; But, Javascript instead provides a new operator and prototypes. So we do the far less elegant: function A(sun) { this.sun = sun; }; A.prototype.dock = 2; a = new A(1); a.dock == 2; But aside from elegance, this is also strictly less powerful, because it means that anything created with A gets the same fallback object. What I would like to do is liberate Javascript from this artificial limitation and have the ability to give any individual object any other individual object as its fallback. That way I could keep the current behavior when it makes sense, but use object-level inheritance when that makes sense. My initial approach is to create a dummy constructor function: function setFallback(from_obj, to_obj) { from_obj.constructor = function () {}; from_obj.constructor.prototype = to_obj; } a = {sun:1}; b = {dock:2}; setFallback(a, b); But unfortunately: a.dock == undefined; Any ideas why this doesn't work, or any solutions for an implementation of setFallback? (I'm running on V8, via node.js, in case this is platform dependent)

    Read the article

  • Is memory allocation in linux non-blocking?

    - by Mark
    I am curious to know if the allocating memory using a default new operator is a non-blocking operation. e.g. struct Node { int a,b; }; ... Node foo = new Node(); If multiple threads tried to create a new Node and if one of them was suspended by the OS in the middle of allocation, would it block other threads from making progress? The reason why I ask is because I had a concurrent data structure that created new nodes. I then modified the algorithm to recycle the nodes. The throughput performance of the two algorithms was virtually identical on a 24 core machine. However, I then created an interference program that ran on all the system cores in order to create as much OS pre-emption as possible. The throughput performance of the algorithm that created new nodes decreased by a factor of 5 relative the the algorithm that recycled nodes. I'm curious to know why this would occur. Thanks. *Edit : pointing me to the code for the c++ memory allocator for linux would be helpful as well. I tried looking before posting this question, but had trouble finding it.

    Read the article

  • Quicksort / vector / partition issue

    - by xxx
    Hi, I have an issue with the following code : class quicksort { private: void _sort(double_it begin, double_it end) { if ( begin == end ) { return ; } double_it it = partition(begin, end, bind2nd(less<double>(), *begin)) ; iter_swap(begin, it-1); _sort(begin, it-1); _sort(it, end); } public: quicksort (){} void operator()(vector<double> & data) { double_it begin = data.begin(); double_it end = data.end() ; _sort(begin, end); } }; However, this won't work for too large a number of elements (it works with 10 000 elements, but not with 100 000). Example code : int main() { vector<double>v ; for(int i = n-1; i >= 0 ; --i) v.push_back(rand()); quicksort f; f(v); return 0; } Doesn't the STL partition function works for such sizes ? Or am I missing something ? Many thanks for your help.

    Read the article

  • C++ find multiple keys from a std::multimap

    - by sch0ck9
    I have a STL::multimap and I search to populate a std::list with value which key is duplicated. Can I find/insert to a std::list the value of elements for all key where count 1 without counting them one by one? std::multimap<int, std::string> mm ; mm[0] = "a" ; mm[1] = "b" ; mm[0] = "c" ; mm[2] = "j" ; mm[2] = "k" ; std::list<std::string> lst ; lst might contains "a" ,"c","j","k" ; I try this template <class K, class V> class extract_value { private: K last_key_ ; std::list<V> m_list_value ; std::pair<K, V> first_elem ; public: extract_value(const K& k_): last_key_(k_) { } void operator() (std::pair<const K, V> elem) { if (last_key_ == elem.first) { m_list_value.push_back(elem.second) ; } else { // First entry last_key_ = elem.first; first_elem= elem ; } } std::list<V> get_value() { return m_list_value ; } }; ex_ = for_each(mm.begin(),mm.end(), extract_value<int, std::string>(0)) ; std::list<std::string> lst = ex_.get_value() ; I'm not sure that this code compile.

    Read the article

  • LINQ to SQL: Reusable expression for property?

    - by coenvdwel
    Pardon me for being unable to phrase the title more exact. Basically, I have three LINQ objects linked to tables. One is Product, the other is Company and the last is a mapping table Mapping to store what Company sells which products and by which ID this Company refers to this Product. I am now retrieving a list of products as follows: var options = new DataLoadOptions(); options.LoadWith<Product>(p => p.Mappings); context.LoadOptions = options; var products = ( from p in context.Products select new { ProductID = p.ProductID, //BackendProductID = p.BackendProductID, BackendProductID = (p.Mappings.Count == 0) ? "None" : (p.Mappings.Count > 1) ? "Multiple" : p.Mappings.First().BackendProductID, Description = p.Description } ).ToList(); This does a single query retrieving the information I want. But I want to be able to move the logic behind the BackendProductID into the LINQ object so I can use the commented line instead of the annoyingly nested ternary operator statements for neatness and re-usability. So I added the following property to the Product object: public string BackendProductID { get { if (Mappings.Count == 0) return "None"; if (Mappings.Count > 1) return "Multiple"; return Mappings.First().BackendProductID; } } The list is still the same, but it now does a query for every single Product to get it's BackendProductID. The code is neater and re-usable, but the performance now is terrible. What I need is some kind of Expression or Delegate but I couldn't get my head around writing one. It always ended up querying for every single product, still. Any help would be appreciated!

    Read the article

  • How do the operators < and > work with pointers?

    - by Øystein
    Just for fun, I had a std::list of const char*, each element pointing to a null-terminated text string, and ran a std::list::sort() on it. As it happens, it sort of (no pun intended) did not sort the strings. Considering that it was working on pointers, that makes sense. According to the documentation of std::list::sort(), it (by default) uses the operator < between the elements to compare. Forgetting about the list for a moment, my actual question is: How do these (, <, =, <=) operators work on pointers in C++ and C? Do they simply compare the actual memory addresses? char* p1 = (char*) 0xDAB0BC47; char* p2 = (char*) 0xBABEC475; e.g. on a 32-bit, little-endian system, p1 p2 because 0xDAB0BC47 0xBABEC475? Testing seems to confirm this, but I thought it'd be good to put it on StackOverflow for future reference. C and C++ both do some weird things to pointers, so you never really know...

    Read the article

  • How can variadic char template arguments from user defined literals be converted back into numeric types?

    - by Pubby
    This question is being asked because of this one. C++11 allows you to define literals like this for numeric literals: template<char...> OutputType operator "" _suffix(); Which means that 503_suffix would become <'5','0','3'> This is nice, although it isn't very useful in the form it's in. How can I transform this back into a numeric type? This would turn <'5','0','3'> into a constexpr 503. Additionally, it must also work on floating point literals. <'5','.','3> would turn into int 5 or float 5.3 A partial solution was found in the previous question, but it doesn't work on non-integers: template <typename t> constexpr t pow(t base, int exp) { return (exp > 0) ? base * pow(base, exp-1) : 1; }; template <char...> struct literal; template <> struct literal<> { static const unsigned int to_int = 0; }; template <char c, char ...cv> struct literal<c, cv...> { static const unsigned int to_int = (c - '0') * pow(10, sizeof...(cv)) + literal<cv...>::to_int; }; // use: literal<...>::to_int // literal<'1','.','5'>::to_int doesn't work // literal<'1','.','5'>::to_float not implemented

    Read the article

  • Determine if a Range contains a value

    - by Brad Dwyer
    I'm trying to figure out a way to determine if a value falls within a Range in Swift. Basically what I'm trying to do is adapt one of the examples switch statement examples to do something like this: let point = (1, -1) switch point { case let (x, y) where (0..5).contains(x): println("(\(x), \(y)) has an x val between 0 and 5.") default: println("This point has an x val outside 0 and 5.") } As far as I can tell, there isn't any built in way to do what my imaginary .contains method above does. So I tried to extend the Range class. I ended up running into issues with generics though. I can't extend Range<Int> so I had to try to extend Range itself. The closest I got was this but it doesn't work since >= and <= aren't defined for ForwardIndex extension Range { func contains(val:ForwardIndex) -> Bool { return val >= self.startIndex && val <= self.endIndex } } How would I go about adding a .contains method to Range? Or is there a better way to determine whether a value falls within a range? Edit2: This seems to work to extend Range extension Range { func contains(val:T) -> Bool { for x in self { if(x == val) { return true } } return false } } var a = 0..5 a.contains(3) // true a.contains(6) // false a.contains(-5) // false I am very interested in the ~= operator mentioned below though; looking into that now.

    Read the article

  • How to improve multi-threaded access to Cache (custom implementation)

    - by Andy
    I have a custom Cache implementation, which allows to cache TCacheable<TKey> descendants using LRU (Least Recently Used) cache replacement algorithm. Every time an element is accessed, it is bubbled up to the top of the LRU queue using the following synchronized function: // a single instance is created to handle all TCacheable<T> elements public class Cache() { private object syncQueue = new object(); private void topQueue(TCacheable<T> el) { lock (syncQueue) if (newest != el) { if (el.elder != null) el.elder.newer = el.newer; if (el.newer != null) el.newer.elder = el.elder; if (oldest == el) oldest = el.newer; if (oldest == null) oldest = el; if (newest != null) newest.newer = el; el.newer = null; el.elder = newest; newest = el; } } } The bottleneck in this function is the lock() operator, which limits cache access to just one thread at a time. Question: Is it possible to get rid of lock(syncQueue) in this function while still preserving the queue integrity?

    Read the article

  • What does it mean to pass a &variable to a function? E.g., string& insert ( size_t pos1, const strin

    - by Bob Montgomery
    I understand passing a pointer, and returning a pointer: char * strcat ( char * destination, const char * source ); You're passing a variable that contains the address to a char; returning the same. But what does it mean to pass something using the reference operator? Or to return it? string& insert ( size_t pos1, const string& str ); I mean, I understand what actually happens, I just don't understand the notation. Why isn't the notation this instead: string * insert ( size_t pos1, const string * str ); //made up I presume it has something to do with passing/returning the instance of a class, but what? Is this syntax valid; if not why not and if so what does it mean? char & strcat ( char & destination, const char & source ); //made up (all of the function declarations, except the last made-up two, are from http://www.cplusplus.com )

    Read the article

  • Combining two data sets and plotting in matlab

    - by bautrey
    I am doing experiments with different operational amplifier circuits and I need to plot my measured results onto a graph. I have two data sets: freq1 = [.1 .2 .5 .7 1 3 4 6 10 20 35 45 60 75 90 100]; %kHz Vo1 = [1.2 1.6 1.2 2 2 2.4 14.8 20.4 26.4 30.4 53.6 68.8 90 114 140 152]; %mV V1 = 19.6; Acm = Vo1/(1000*V1); And: freq2 = [.1 .5 1 30 60 70 85 100]; %kHz Vo1 = [3.96 3.96 3.96 3.84 3.86 3.88 3.88 3.88]; %V V1 = .96; Ad = Vo1/(2*V1); (I would show my plots but apparently I need more reps for that) I need to plot the equation, CMRR vs freq: CMRR = 20*log10(abs(Ad/Acm)); The size of Ad and Acm are different and the frequency points do not match up, but the boundaries of both of these is the same, 100Hz to 100kHz (x-axis). On the line of CMRR, Matlab says that Ad and Acm matrix dimensions do not agree. How I think I would solve this is using freq1 as the x-axis for CMRR and then taking approximated points from Ad according to the value on freq1. Or I could do function approximations of Ad and Acm and then do the divide operator on those. I do not know how I would code up this two ideas. Any other ideas would helpful, especially simpler ones. Thanks

    Read the article

  • LINQ to Entites - Left Outer Join - SQL 2000

    - by user255234
    Hi! I'm using Linq to Entities. I have the following query in my code, it includes left outer Join: var surgeonList = (from item in context.T1_STM_Surgeon.Include("T1_STM_SurgeonTitle") .Include("OTER").Include("OSLP") join reptable in context.OSLP on item.Rep equals reptable.SlpCode into surgRepresentative where item.ID == surgeonId select new { ID = item.ID, First = item.First, Last = item.Last, Rep = (surgRepresentative.FirstOrDefault() != null) ? surgRepresentative.FirstOrDefault().SlpName : "N/A", Reg = item.OTER.descript, PrimClinic = item.T1_STM_ClinicalCenter.Name, Titles = item.T1_STM_SurgeonTitle, Phone = item.Phone, Email = item.Email, Address1 = item.Address1, Address2 = item.Address2, City = item.City, State = item.State, Zip = item.Zip, Comments = item.Comments, Active = item.Active, DateEntered = item.DateEntered }) .ToList(); My DEV server has SQL 2008, so the code works just fine. When I moved this code to client's production server - they use SQL 2000, I started getting "Incorrect syntax near '(' ". I've tried changing the ProviderManifestToken to 2000 in my .edmx file, then I started getting "The execution of this query requires the APPLY operator, which is not supported in versions of SQL Server earlier than SQL Server 2005." I tied changing the token to 2005, the "Incorrect syntax near '(' " is back. Can anybody help me to find a workaround for this? Thank you very much in advance!

    Read the article

  • GUID or int entity key with SQL Compact/EF4?

    - by David Veeneman
    This is a follow-up to an earlier question I posted on EF4 entity keys with SQL Compact. SQL Compact doesn't allow server-generated identity keys, so I am left with creating my own keys as objects are added to the ObjectContext. My first choice would be an integer key, and the previous answer linked to a blog post that shows an extension method that uses the Max operator with a selector expression to find the next available key: public static TResult NextId<TSource, TResult>(this ObjectSet<TSource> table, Expression<Func<TSource, TResult>> selector) where TSource : class { TResult lastId = table.Any() ? table.Max(selector) : default(TResult); if (lastId is int) { lastId = (TResult)(object)(((int)(object)lastId) + 1); } return lastId; } Here's my take on the extension method: It will work fine if the ObjectContext that I am working with has an unfiltered entity set. In that case, the ObjectContext will contain all rows from the data table, and I will get an accurate result. But if the entity set is the result of a query filter, the method will return the last entity key in the filtered entity set, which will not necessarily be the last key in the data table. So I think the extension method won't really work. At this point, the obvious solution seems to be to simply use a GUID as the entity key. That way, I only need to call Guid.NewGuid() method to set the ID property before I add a new entity to my ObjectContext. Here is my question: Is there a simple way of getting the last primary key in the data store from EF4 (without having to create a second ObjectContext for that purpose)? Any other reason not to take the easy way out and simply use a GUID? Thanks for your help.

    Read the article

  • Using an ActiveX control without a form/dialog/window in C++, VS 2008

    - by younevertell
    an ActiveX control generated by Visual Basic 6, very old stuff, it has a couple of methods and one event. now I have to use the control in C++, visual studio 2008, but I don't like to generate a form/dialog/window as constainer. I add some MFC class From ActiveX Control. Now the wrap class has all the methods defined in the ActiveX control. I definitely need add event handler to take care of the event fired by ActiveX control. With a form/dialgue/window, it could be done by below BEGIN_EVENTSINK_MAP ON_EVENT. My questions are 1. how to add the event handler without a form/dialgue/window. Is this impossible? 2. Could I manually add constructor in the ActiveX control wrap class, so I could use new operator to get an instance on the heap? Thanks Add the Event Sinks Map near the start of the definition (.cpp) file. The BEGIN_EVENTSINK_MAP macro takes the container's Class name, then the base class name as parameters. The container's class name is used again in the AFX_EVENTSINK_MAP macro and the ON_EVENT macro.

    Read the article

  • PDFParsing & extracting the images only in iPhone application.

    - by sagar
    Hello - Every one. ** : My Query : ** I want to extract only images from entire pdf document. ( Using Objective C - for iPhone Application ) : My Efforts : I have gone through this link which has details regarding different operators of PDF Document. ( http://mail-archives.apache.org/mod_mbox/pdfbox-commits/200912.mbox/%[email protected]%3E ) I also studied this document - ( http://developer.apple.com/mac/library/documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_pdf_scan/dq_pdf_scan.html#//apple_ref/doc/uid/TP30001066-CH220-TPXREF101 ) I also have gone through entire document of PDFReference.pdf ( From original Adobe Site ) PDFReference.pdf (Adobe Document - says that - for image there are following operators ) q Q BI EI I have placed following table get the image myTable = CGPDFOperatorTableCreate(); CGPDFOperatorTableSetCallback(myTable, "q", arrayCallback2); CGPDFOperatorTableSetCallback(myTable, "TJ", arrayCallback); CGPDFOperatorTableSetCallback(myTable, "Tj", stringCallback); I have following arrayCallback2 method for getting image void arrayCallback2(CGPDFScannerRef inScanner, void *userInfo) { // how to extract image from this code // means I have tried too many different ways. following is incorrect way & not giving image // CGPDFStreamRef stream; // represents a sequence of bytes // if (CGPDFDictionaryGetStream (d, "BI", &stream)){ // CGPDFDataFormat t=CGPDFDataFormatJPEG2000; // CFDataRef data = CGPDFStreamCopyData (stream, &t); // } } above arrayCallback2 method is called for operator "q", But I don't know How to extract the image from it. In short. What should be the solution for extracting the images from the pdf documents? Thanks in advance for your kind help. Sagar kothari.

    Read the article

  • Databinding expression for retrieving value of related collection using LINQ

    - by joshb
    I have a GridView that is bound to a LINQDataSource control that is returning a collection of customers. Within my DataGrid I need to display the home phone number of a customer, if they have one. The phone numbers of a customer are stored in a separate table with a foreign key pointing to the customer table. The following binding expression gets me the first phone number for a customer: <asp:TemplateField HeaderText="LastName" SortExpression="LastName"> <ItemTemplate> <asp:Label ID="PhoneLabel" runat="server" Text='<%# Eval("Phones[0].PhoneNumber") %>'></asp:Label> </ItemTemplate> </asp:TemplateField> I need to figure out how to get the home phone number specifically (filter based on phone type) and handle the scenario where the customer does not have a home phone in the database. Right now it's throwing an out of range exception if the customer does not have any phone numbers. I've tried using the Where operator with a lambda expression to filter the phone type but it doesn't work: <%# Eval("Phones.Where(p => p.PhoneTypeId == 2).PhoneNumber") %> Solutions or links to any good articles on the subject would be much appreciated.

    Read the article

  • [C++] My First Go With Function Templates

    - by bobber205
    Thought it was pretty straight forward. But I get a "iterator not dereferencable" errro when running the below code. What's wrong? template<typename T> struct SumsTo : public std::binary_function<T, T, bool> { int myInt; SumsTo(int a) { myInt = a; } bool operator()(const T& l, const T& r) { cout << l << " + " << r; if ((l + r) == myInt) { cout << " does add to " << myInt; } else { cout << " DOES NOT add to " << myInt; } return true; } }; void main() { list<int> l1; l1.push_back(1); l1.push_back(2); l1.push_back(3); l1.push_back(4); list<int> l2; l2.push_back(9); l2.push_back(8); l2.push_back(7); l2.push_back(6); transform(l1.begin(), l1.end(), l2.begin(), l2.end(), SumsTo<int>(10) ); }

    Read the article

  • Modify passed, nested dict/list

    - by Gerenuk
    I was thinking of writing a function to normalize some data. A simple approach is def normalize(l, aggregate=sum, norm_by=operator.truediv): aggregated=aggregate(l) for i in range(len(l)): l[i]=norm_by(l[i], aggregated) l=[1,2,3,4] normalize(l) l -> [0.1, 0.2, 0.3, 0.4] However for nested lists and dicts where I want to normalize over an inner index this doesnt work. I mean I'd like to get l=[[1,100],[2,100],[3,100],[4,100]] normalize(l, ?? ) l -> [[0.1,100],[0.2,100],[0.3,100],[0.4,100]] Any ideas how I could implement such a normalize function? Maybe it would be crazy cool to write normalize(l[...][0]) Is it possible to make this work?? Or any other ideas? Also not only lists but also dict could be nested. Hmm... EDIT: I just found out that numpy offers such a syntax (for lists however). Anyone know how I would implement the ellipsis trick myself?

    Read the article

  • How to write a custom predicate for multi_index_containder with composite_key?

    - by Titan
    I googled and searched in the boost's man, but didn't find any examples. May be it's a stupid question...anyway. So we have the famous phonebook from the man: typedef multi_index_container< phonebook_entry, indexed_by< ordered_non_unique< composite_key< phonebook_entry, member<phonebook_entry,std::string,&phonebook_entry::family_name>, member<phonebook_entry,std::string,&phonebook_entry::given_name> >, composite_key_compare< std::less<std::string>, // family names sorted as by default std::greater<std::string> // given names reversed > >, ordered_unique< member<phonebook_entry,std::string,&phonebook_entry::phone_number> > > > phonebook; phonebook pb; ... // look for all Whites std::pair<phonebook::iterator,phonebook::iterator> p= pb.equal_range(boost::make_tuple("White"), my_custom_comp()); How should my_custom_comp() look like? I mean it's clear for me then it takes boost::multi_index::composite_key_result<CompositeKey> as an argumen (due to compilation errors :) ), but what is CompositeKey in that particular case? struct my_custom_comp { bool operator()( ?? boost::multi_index::composite_key_result<CompositeKey> ?? ) const { return blah_blah_blah; } }; Thanks in advance.

    Read the article

  • Template trick to optimize out allocations

    - by anon
    I have: struct DoubleVec { std::vector<double> data; }; DoubleVec operator+(const DoubleVec& lhs, const DoubleVec& rhs) { DoubleVec ans(lhs.size()); for(int i = 0; i < lhs.size(); ++i) { ans[i] = lhs[i]] + rhs[i]; // assume lhs.size() == rhs.size() } return ans; } DoubleVec someFunc(DoubleVec a, DoubleVec b, DoubleVec c, DoubleVec d) { DoubleVec ans = a + b + c + d; } Now, in the above, the "a + b + c + d" will cause the creation of 3 temporary DoubleVec's -- is there a way to optimize this away with some type of template magic ... i.e. to optimize it down to something equivalent to: DoubleVec ans(a.size()); for(int i = 0; i < ans.size(); i++) ans[i] = a[i] + b[i] + c[i] + d[i]; You can assume all DoubleVec's have the same # of elements. The high level idea is to have do some type of templateied magic on "+", which "delays the computation" until the =, at which point it looks into itself, goes hmm ... I'm just adding thes numbers, and syntheizes a[i] + b[i] + c[i] + d[i] ... instead of all the temporaries. Thanks!

    Read the article

< Previous Page | 85 86 87 88 89 90 91 92 93 94 95 96  | Next Page >