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  • How can I extend DynamicQuery.cs to implement a .Single method?

    - by Yoenhofen
    I need to write some dynamic queries for a project I'm working on. I'm finding out that a significant amount of time is being spent by my program on the Count and First methods, so I started to change to .Single, only to find out that there is no such method. The code below was my first attempt at creating one (mostly copied from the Where method), but it's not working. Help? public static object Single(this IQueryable source, string predicate, params object[] values) { if (source == null) throw new ArgumentNullException("source"); if (predicate == null) throw new ArgumentNullException("predicate"); LambdaExpression lambda = DynamicExpression.ParseLambda(source.ElementType, typeof(bool), predicate, values); return source.Provider.CreateQuery( Expression.Call( typeof(Queryable), "Single", new Type[] { source.ElementType }, source.Expression, Expression.Quote(lambda))); }

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  • Why 32-bit color EGL configurations fail with EGL_BAD_MATCH on Moto Droid?

    - by Gilead
    I'm trying to figure out why certain EGL configurations cause eglMakeCurrent() call to return EGL_BAD_MATCH on Motorola Droid running Android 2.1u1. This is a full list of hardware-accelerated EGL configurations (those with EGL_CONFIG_CAVEAT == EGL_NONE) as there's a few others with EGL_CONFIG_CAVEAT == EGL_SLOW_CONFIG but those are backed by PixelFlinger 1.2 meaning they're using software renderer. ID: 0 RGB: 8, 8, 8 Alpha: 8 Depth: 24 Stencil: 8 // BAD MATCH ID: 1 RGB: 8, 8, 8 Alpha: 8 Depth: 0 Stencil: 0 // BAD MATCH ID: 2 RGB: 8, 8, 8 Alpha: 8 Depth: 24 Stencil: 8 // BAD MATCH ID: 3 RGB: 8, 8, 8 Alpha: 8 Depth: 24 Stencil: 8 // BAD MATCH ID: 4 RGB: 8, 8, 8 Alpha: 8 Depth: 0 Stencil: 0 // BAD MATCH ID: 5 RGB: 8, 8, 8 Alpha: 8 Depth: 24 Stencil: 8 // BAD MATCH ID: 6 RGB: 5, 6, 5 Alpha: 0 Depth: 24 Stencil: 8 ID: 7 RGB: 5, 6, 5 Alpha: 0 Depth: 0 Stencil: 0 ID: 8 RGB: 5, 6, 5 Alpha: 0 Depth: 24 Stencil: 8 Clearly, all configurations with 32-bit color depth fail and all 16-bit ones are OK but: 1. Why? 2. WHY?! :) 3. How do I tell which ones would fail before actually trying to use them? The code below is as simple as it can get. I put if (v[0] == 6) there to check different configs, normally they're chosen by half-clever config matcher :) private void createSurface(SurfaceHolder holder) { egl = (EGL10)EGLContext.getEGL(); eglDisplay = egl.eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY); egl.eglInitialize(eglDisplay, null); int[] numConfigs = new int[1]; egl.eglChooseConfig(eglDisplay, new int[] { EGL10.EGL_NONE }, null, 0, numConfigs); EGLConfig[] configs = new EGLConfig[numConfigs[0]]; egl.eglChooseConfig(eglDisplay, new int[] { EGL10.EGL_NONE }, configs, numConfigs[0], numConfigs); int[] v = new int[1]; for (EGLConfig c : configs) { egl.eglGetConfigAttrib(eglDisplay, c, EGL10.EGL_CONFIG_ID, v); if (v[0] == 6) { eglConfig = c; } } eglContext = egl.eglCreateContext(eglDisplay, eglConfig, EGL10.EGL_NO_CONTEXT, null); if (eglContext == null || eglContext == EGL10.EGL_NO_CONTEXT) { throw new RuntimeException("Unable to create EGL context"); } eglSurface = egl.eglCreateWindowSurface(eglDisplay, eglConfig, holder, null); if (eglSurface == null || eglSurface == EGL10.EGL_NO_SURFACE) { throw new RuntimeException("Unable to create EGL surface"); } if (!egl.eglMakeCurrent(eglDisplay, eglSurface, eglSurface, eglContext)) { throw new RuntimeException("Unable to make EGL current"); } gl = (GL10)eglContext.getGL(); }

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  • Custom Model binder not firing

    - by mare
    This is my custom model binder. I have my breakpoint set at BindModel but does not get fired with this controller action: public ActionResult Create(TabGroup tabGroup) ... public class BaseContentObjectCommonPropertiesBinder : DefaultModelBinder { public new object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) { if (controllerContext == null) { throw new ArgumentNullException("controllerContext"); } if (bindingContext == null) { throw new ArgumentNullException("bindingContext"); } BaseContentObject obj = (BaseContentObject)base.BindModel(controllerContext, bindingContext); obj.Modified = DateTime.Now; obj.Created = DateTime.Now; obj.ModifiedBy = obj.CreatedBy = controllerContext.HttpContext.User.Identity.Name; return obj; } My registration: // tried both of these two lines ModelBinders.Binders[typeof(TabGroup)] = new BaseContentObjectCommonPropertiesBinder(); ModelBinders.Binders.Add(typeof(TabGroup), new BaseContentObjectCommonPropertiesBinder());

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  • How can I convert Perl one-liners into complete scripts?

    - by Stefan Lasiewski
    I find a lot of Perl one-liners online. Sometimes I want to convert these one-liners into a script, because otherwise I'll forget the syntax of the one-liner. For example, I'm using the following command (from nagios.com): tail -f /var/log/nagios/nagios.log | perl -pe 's/(\d+)/localtime($1)/e' I'd to replace it with something like this: tail -f /var/log/nagios/nagios.log | ~/bin/nagiostime.pl However, I can't figure out the best way to quickly throw this stuff into a script. Does anyone have a quick way to throw these one-liners into a Bash or Perl script?

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  • Facebook Graph API - authorization types?

    - by Alex Cook
    I'm struggling with the new Facebook Graph API, perhaps someone here can help. Here is what I want to do: provide a ‘login w/ FB’ button, throw to /authorize, get a code, throw to /access_token, get an access_token, and be able to hit https://graph.facebook.com/me for info about the user. When I try to use type=client_cred in the /authorize call, I get an access_token that lets me hit URLs with userIDs or names, but not /me. I receive an error stating I need a valid token. If I can't hit /me, how do I figure out who the current user is? What exactly should I use in the type param if I want a website to access a users data? I've seen posts with type=web_server, etc, but I can't seem to find a sure fire way to do, what I think, is pretty simple... Thanks ahead of time for any help thats provided...

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  • Method may fail to close stream on exception

    - by 01
    I get the critical error with finbugs The method creates an IO stream object, does not assign it to any fields, pass it to other methods, or return it, and does not appear to close it on all possible exception paths out of the method. This may result in a file descriptor leak. It is generally a good idea to use a finally block to ensure that streams are closed. try { ... stdError = new BufferedReader(new InputStreamReader(p.getErrorStream())); ... } catch (IOException e) { throw new RuntimeException(e); } finally { try { if (stdInput != null) { stdInput.close(); } if (stdError != null) { stdError.close(); } } catch (IOException e) { throw new RuntimeException(e); } } do i need to close also InputStreamReader or p.getErrorStream(it returns InputStream) ??

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  • Still getting duplicate token error after calling DuplicateTokenEx for impersonated token

    - by atconway
    I'm trying to return a Sytem.IntPtr from a service call so that the client can use impersonation to call some code. My imersonation code works properly if not passing the token back from a WCF service. I'm not sure why this is not working. I get the following error: "Invalid token for impersonation - it cannot be duplicated." Here is my code that does work except when I try to pass the token back from a service to a WinForm C# client to then impersonate. [DllImport("advapi32.dll", EntryPoint = "DuplicateTokenEx")] public extern static bool DuplicateTokenEx(IntPtr ExistingTokenHandle, uint dwDesiredAccess, ref SECURITY_ATTRIBUTES lpThreadAttributes, int TokenType, int ImpersonationLevel, ref IntPtr DuplicateTokenHandle); private IntPtr tokenHandle = new IntPtr(0); private IntPtr dupeTokenHandle = new IntPtr(0); [StructLayout(LayoutKind.Sequential)] public struct SECURITY_ATTRIBUTES { public int Length; public IntPtr lpSecurityDescriptor; public bool bInheritHandle; } public enum SecurityImpersonationLevel { SecurityAnonymous = 0, SecurityIdentification = 1, SecurityImpersonation = 2, SecurityDelegation = 3 } public enum TokenType { TokenPrimary = 1, TokenImpersonation = 2 } private const int MAXIMUM_ALLOWED = 0x2000000; [PermissionSetAttribute(SecurityAction.Demand, Name = "FullTrust")] public System.IntPtr GetWindowsUserToken(string UserName, string Password, string DomainName) { IntPtr tokenHandle = new IntPtr(0); IntPtr dupTokenHandle = new IntPtr(0); const int LOGON32_PROVIDER_DEFAULT = 0; //This parameter causes LogonUser to create a primary token. const int LOGON32_LOGON_INTERACTIVE = 2; //Initialize the token handle tokenHandle = IntPtr.Zero; //Call LogonUser to obtain a handle to an access token for credentials supplied. bool returnValue = LogonUser(UserName, DomainName, Password, LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT, ref tokenHandle); //Make sure a token was returned; if no populate the ResultCode and throw an exception: int ResultCode = 0; if (false == returnValue) { ResultCode = Marshal.GetLastWin32Error(); throw new System.ComponentModel.Win32Exception(ResultCode, "API call to LogonUser failed with error code : " + ResultCode); } SECURITY_ATTRIBUTES sa = new SECURITY_ATTRIBUTES(); sa.bInheritHandle = true; sa.Length = Marshal.SizeOf(sa); sa.lpSecurityDescriptor = (IntPtr)0; bool dupReturnValue = DuplicateTokenEx(tokenHandle, MAXIMUM_ALLOWED, ref sa, (int)SecurityImpersonationLevel.SecurityDelegation, (int)TokenType.TokenImpersonation, ref dupTokenHandle); int ResultCodeDup = 0; if (false == dupReturnValue) { ResultCodeDup = Marshal.GetLastWin32Error(); throw new System.ComponentModel.Win32Exception(ResultCode, "API call to DuplicateToken failed with error code : " + ResultCode); } //Return the user token return dupTokenHandle; } Any idea if I'm not using the call to DuplicateTokenEx correctly? According to the MSDN documentation I read here I should be able to create a token valid for delegation and use across the context on remote systems. When 'SecurityDelegation' is used, the server process can impersonate the client's security context on remote systems. Thanks!

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  • Lock statement vs Monitor.Enter method.

    - by Vokinneberg
    I suppose it is an interesting code example. We have a class, let's call it Test with Finalize method. In Main method here is two code blocks where i am using lock statement and Monitor.Enter call. Also i have two instances of class Test here. The experiment is pretty simple - nulling Test variable within locking block and try to collect it manually with GC.Collect method call. So, to see the Finilaze call i am calling GC.WaitForPendingFinalizers method. Everything is very simple as you can see. By defenition of lock statement it's opens by compiler to try{...}finally{..} block with Minitor.Enter call inside of try block and Monitor.Exit in finally block. I've tryed to implement try-finally block manually. I've expected the same behaviour in both cases. in case of using lock and in case of unsing Monitor.Enter. But, surprize, surprize - it is different as you can see below. public class Test : IDisposable { private string name; public Test(string name) { this.name = name; } ~Test() { Console.WriteLine(string.Format("Finalizing class name {0}.", name)); } } class Program { static void Main(string[] args) { var test1 = new Test("Test1"); var test2 = new Test("Tesst2"); lock (test1) { test1 = null; Console.WriteLine("Manual collect 1."); GC.Collect(); GC.WaitForPendingFinalizers(); Console.WriteLine("Manual collect 2."); GC.Collect(); } var lockTaken = false; System.Threading.Monitor.Enter(test2, ref lockTaken); try { test2 = null; Console.WriteLine("Manual collect 3."); GC.Collect(); GC.WaitForPendingFinalizers(); Console.WriteLine("Manual collect 4."); GC.Collect(); } finally { System.Threading.Monitor.Exit(test2); } Console.ReadLine(); } } Output of this example is Manual collect 1. Manual collect 2. Manual collect 3. Finalizing class name Test2. Manual collect 4. And null reference exception in last finally block because test2 is null reference. I've was surprised and disasembly my code into IL. So, here is IL dump of Main method. .entrypoint .maxstack 2 .locals init ( [0] class ConsoleApplication2.Test test1, [1] class ConsoleApplication2.Test test2, [2] bool lockTaken, [3] bool <>s__LockTaken0, [4] class ConsoleApplication2.Test CS$2$0000, [5] bool CS$4$0001) L_0000: nop L_0001: ldstr "Test1" L_0006: newobj instance void ConsoleApplication2.Test::.ctor(string) L_000b: stloc.0 L_000c: ldstr "Tesst2" L_0011: newobj instance void ConsoleApplication2.Test::.ctor(string) L_0016: stloc.1 L_0017: ldc.i4.0 L_0018: stloc.3 L_0019: ldloc.0 L_001a: dup L_001b: stloc.s CS$2$0000 L_001d: ldloca.s <>s__LockTaken0 L_001f: call void [mscorlib]System.Threading.Monitor::Enter(object, bool&) L_0024: nop L_0025: nop L_0026: ldnull L_0027: stloc.0 L_0028: ldstr "Manual collect." L_002d: call void [mscorlib]System.Console::WriteLine(string) L_0032: nop L_0033: call void [mscorlib]System.GC::Collect() L_0038: nop L_0039: call void [mscorlib]System.GC::WaitForPendingFinalizers() L_003e: nop L_003f: ldstr "Manual collect." L_0044: call void [mscorlib]System.Console::WriteLine(string) L_0049: nop L_004a: call void [mscorlib]System.GC::Collect() L_004f: nop L_0050: nop L_0051: leave.s L_0066 L_0053: ldloc.3 L_0054: ldc.i4.0 L_0055: ceq L_0057: stloc.s CS$4$0001 L_0059: ldloc.s CS$4$0001 L_005b: brtrue.s L_0065 L_005d: ldloc.s CS$2$0000 L_005f: call void [mscorlib]System.Threading.Monitor::Exit(object) L_0064: nop L_0065: endfinally L_0066: nop L_0067: ldc.i4.0 L_0068: stloc.2 L_0069: ldloc.1 L_006a: ldloca.s lockTaken L_006c: call void [mscorlib]System.Threading.Monitor::Enter(object, bool&) L_0071: nop L_0072: nop L_0073: ldnull L_0074: stloc.1 L_0075: ldstr "Manual collect." L_007a: call void [mscorlib]System.Console::WriteLine(string) L_007f: nop L_0080: call void [mscorlib]System.GC::Collect() L_0085: nop L_0086: call void [mscorlib]System.GC::WaitForPendingFinalizers() L_008b: nop L_008c: ldstr "Manual collect." L_0091: call void [mscorlib]System.Console::WriteLine(string) L_0096: nop L_0097: call void [mscorlib]System.GC::Collect() L_009c: nop L_009d: nop L_009e: leave.s L_00aa L_00a0: nop L_00a1: ldloc.1 L_00a2: call void [mscorlib]System.Threading.Monitor::Exit(object) L_00a7: nop L_00a8: nop L_00a9: endfinally L_00aa: nop L_00ab: call string [mscorlib]System.Console::ReadLine() L_00b0: pop L_00b1: ret .try L_0019 to L_0053 finally handler L_0053 to L_0066 .try L_0072 to L_00a0 finally handler L_00a0 to L_00aa I does not see any difference between lock statement and Monitor.Enter call. So, why i steel have a reference to the instance of test1 in case of lock, and object is not collected by GC, but in case of using Monitor.Enter it is collected and finilized?

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  • When to log exception?

    - by Rune
    try { // Code } catch (Exception ex) { Logger.Log("Message", ex); throw; } In the case of a library, should I even log the exception? Should I just throw it and allow the application to log it? My concern is that if I log the exception in the library, there will be many duplicates (because the library layer will log it, the application layer will log it, and anything in between), but if I don't log it in the library, it'll be hard to track down bugs. Is there a best practices for this?

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  • Accessing a Service from within an XNA Content Pipeline Extension

    - by David Wallace
    I need to allow my content pipeline extension to use a pattern similar to a factory. I start with a dictionary type: public delegate T Mapper<T>(MapFactory<T> mf, XElement d); public class MapFactory<T> { Dictionary<string, Mapper<T>> map = new Dictionary<string, Mapper<T>>(); public void Add(string s, Mapper<T> m) { map.Add(s, m); } public T Get(XElement xe) { if (xe == null) throw new ArgumentNullException( "Invalid document"); var key = xe.Name.ToString(); if (!map.ContainsKey(key)) throw new ArgumentException( key + " is not a valid key."); return map[key](this, xe); } public IEnumerable<T> GetAll(XElement xe) { if (xe == null) throw new ArgumentNullException( "Invalid document"); foreach (var e in xe.Elements()) { var val = e.Name.ToString(); if (map.ContainsKey(val)) yield return map[val](this, e); } } } Here is one type of object I want to store: public partial class TestContent { // Test type public string title; // Once test if true public bool once; // Parameters public Dictionary<string, object> args; public TestContent() { title = string.Empty; args = new Dictionary<string, object>(); } public TestContent(XElement xe) { title = xe.Name.ToString(); args = new Dictionary<string, object>(); xe.ParseAttribute("once", once); } } XElement.ParseAttribute is an extension method that works as one might expect. It returns a boolean that is true if successful. The issue is that I have many different types of tests, each of which populates the object in a way unique to the specific test. The element name is the key to MapFactory's dictionary. This type of test, while atypical, illustrates my problem. public class LogicTest : TestBase { string opkey; List<TestBase> items; public override bool Test(BehaviorArgs args) { if (items == null) return false; if (items.Count == 0) return false; bool result = items[0].Test(args); for (int i = 1; i < items.Count; i++) { bool other = items[i].Test(args); switch (opkey) { case "And": result &= other; if (!result) return false; break; case "Or": result |= other; if (result) return true; break; case "Xor": result ^= other; break; case "Nand": result = !(result & other); break; case "Nor": result = !(result | other); break; default: result = false; break; } } return result; } public static TestContent Build(MapFactory<TestContent> mf, XElement xe) { var result = new TestContent(xe); string key = "Or"; xe.GetAttribute("op", key); result.args.Add("key", key); var names = mf.GetAll(xe).ToList(); if (names.Count() < 2) throw new ArgumentException( "LogicTest requires at least two entries."); result.args.Add("items", names); return result; } } My actual code is more involved as the factory has two dictionaries, one that turns an XElement into a content type to write and another used by the reader to create the actual game objects. I need to build these factories in code because they map strings to delegates. I have a service that contains several of these factories. The mission is to make these factory classes available to a content processor. Neither the processor itself nor the context it uses as a parameter have any known hooks to attach an IServiceProvider or equivalent. Any ideas?

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  • Exercise 26 of The Pragmatic Programmer

    - by _ande_turner_
    There is a code snippet presented in The Pragmatic Programmer on page 143 as: public class Colada { private Blender myBlender; private Vector myStuff; public Colada() { myBlender = new Blender(); myStuff = new Vector(); } private doSomething() { myBlender.addIngredients(myStuff.elements()); } } This obeys the Law of Demeter / Principle of Least Knowledge. Is it preferable to, and are there any caveats for, replacing it with the following, which utilises Dependency Injection? public class Colada throws IllegalArgumentException { private Blender myBlender; private Vector myStuff; public Colada(Blender blender, Vector stuff) { blender == null ? throw new IllegalArgumentException() : myBlender = blender; stuff == null ? throw new IllegalArgumentException() : myStuff = stuff; } public getInstance() { Blender blender = new Blender(); Vector stuff = new Vector(); return new Colada(blender, stuff); } private doSomething() { myBlender.addIngredients(myStuff.elements()); } }

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  • Perl equivalent to Java's "throws" clausule.

    - by Konerak
    Is there a way in Perl to declare that a method can throw an error (or die)? I always loved how in Java, a method could handle an Exception and/or throw it. The method signature allows to put "throws MyException", so a good IDE/compiler would know that if you use said method somewhere in your code, you'd have to check for the Exception or declare your function to "throws" the Exception further. I'm unable to find something alike in Perl. A collegue of mine wrote a method which "dies" on incorrect input, but I forget to eval-if($@) it... offcourse the error was only discovered while a user was running the application. (offcourse I doubt if there is any existing IDE that could find these kind of things for Perl, but atleast perl -cw should be able to, no?)

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  • List all possible combinations of k integers between 1...n (n choose k)

    - by Asaf R
    Hi, Out of no particular reason I decided to look for an algorithm that produces all possible choices of k integers between 1...n, where the order amongst the k integer doesn't matter (the n choose k thingy). From the exact same reason, which is no reason at all, I also implemented it in C#. My question is: Do you see any mistake in my algorithm or code? And, more importantly, can you suggest a better algorithm? Please pay more attention to the algorithm than the code itself. It's not the prettiest code I've ever written, although do tell if you see an error. EDIT: Alogirthm explained - We hold k indices. This creates k nested for loops, where loop i's index is indices[i]. It simulates k for loops where indices[i+1] belongs to a loop nested within the loop of indices[i]. indices[i] runs from indices[i - 1] + 1 to n - k + i + 1. CODE: public class AllPossibleCombination { int n, k; int[] indices; List<int[]> combinations = null; public AllPossibleCombination(int n_, int k_) { if (n_ <= 0) { throw new ArgumentException("n_ must be in N+"); } if (k_ <= 0) { throw new ArgumentException("k_ must be in N+"); } if (k_ > n_) { throw new ArgumentException("k_ can be at most n_"); } n = n_; k = k_; indices = new int[k]; indices[0] = 1; } /// <summary> /// Returns all possible k combination of 0..n-1 /// </summary> /// <returns></returns> public List<int[]> GetCombinations() { if (combinations == null) { combinations = new List<int[]>(); Iterate(0); } return combinations; } private void Iterate(int ii) { // // Initialize // if (ii > 0) { indices[ii] = indices[ii - 1] + 1; } for (; indices[ii] <= (n - k + ii + 1); indices[ii]++) { if (ii < k - 1) { Iterate(ii + 1); } else { int[] combination = new int[k]; indices.CopyTo(combination, 0); combinations.Add(combination); } } } } I apologize for the long question, it might be fit for a blog post, but I do want the community's opinion here. Thanks, Asaf

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  • How do I auto size columns through the Excel interop objects?

    - by norlando02
    Below is the code I'm using to load the data into an Excel worksheet, but I'm look to auto size the column after the data is loaded. Does anyone know the best way to auto size the columns? using Microsoft.Office.Interop; public class ExportReport { public void Export() { Excel.Application excelApp = new Microsoft.Office.Interop.Excel.Application(); Excel.Workbook wb; Excel.Worksheet ws; Excel.Range aRange; object m = Type.Missing; string[,] data; string errorMessage = string.Empty; try { if (excelApp == null) throw new Exception("EXCEL could not be started."); // Create the workbook and worksheet. wb = excelApp.Workbooks.Add(Office.Excel.XlWBATemplate.xlWBATWorksheet); ws = (Office.Excel.Worksheet)wb.Worksheets[1]; if (ws == null) throw new Exception("Could not create worksheet."); // Set the range to fill. aRange = ws.get_Range("A1", "E100"); if (aRange == null) throw new Exception("Could not get a range."); // Load the column headers. data = new string[100, 5]; data[0, 0] = "Column 1"; data[0, 1] = "Column 2"; data[0, 2] = "Column 3"; data[0, 3] = "Column 4"; data[0, 4] = "Column 5"; // Load the data. for (int row = 1; row < 100; row++) { for (int col = 0; col < 5; col++) { data[row, col] = "STUFF"; } } // Save all data to the worksheet. aRange.set_Value(m, data); // Atuo size columns // TODO: Add Code to auto size columns. // Save the file. wb.SaveAs("C:\Test.xls", Office.Excel.XlFileFormat.xlExcel8, m, m, m, m, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlNoChange, m, m, m, m, m); // Close the file. wb.Close(false, false, m); } catch (Exception) { } finally { // Close the connection. cmd.Close(); // Close Excel. excelApp.Quit(); } } }

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  • How can arguments to variadic functions be passed by reference in PHP?

    - by outis
    Assuming it's possible, how would one pass arguments by reference to a variadic function without generating a warning in PHP? We can no longer use the '&' operator in a function call, otherwise I'd accept that (even though it would be error prone, should a coder forget it). What inspired this is are old MySQLi wrapper classes that I unearthed (these days, I'd just use PDO). The only difference between the wrappers and the MySQLi classes is the wrappers throw exceptions rather than returning FALSE. class DBException extends RuntimeException {} ... class MySQLi_throwing extends mysqli { ... function prepare($query) { $stmt = parent::prepare($query); if (!$stmt) { throw new DBException($this->error, $this->errno); } return new MySQLi_stmt_throwing($this, $query, $stmt); } } // I don't remember why I switched from extension to composition, but // it shouldn't matter for this question. class MySQLi_stmt_throwing /* extends MySQLi_stmt */ { protected $_link, $_query, $_delegate; public function __construct($link, $query, $prepared) { //parent::__construct($link, $query); $this->_link = $link; $this->_query = $query; $this->_delegate = $prepared; } function bind_param($name, &$var) { return $this->_delegate->bind_param($name, $var); } function __call($name, $args) { //$rslt = call_user_func_array(array($this, 'parent::' . $name), $args); $rslt = call_user_func_array(array($this->_delegate, $name), $args); if (False === $rslt) { throw new DBException($this->_link->error, $this->errno); } return $rslt; } } The difficulty lies in calling methods such as bind_result on the wrapper. Constant-arity functions (e.g. bind_param) can be explicitly defined, allowing for pass-by-reference. bind_result, however, needs all arguments to be pass-by-reference. If you call bind_result on an instance of MySQLi_stmt_throwing as-is, the arguments are passed by value and the binding won't take. try { $id = Null; $stmt = $db->prepare('SELECT id FROM tbl WHERE ...'); $stmt->execute() $stmt->bind_result($id); // $id is still null at this point ... } catch (DBException $exc) { ... } Since the above classes are no longer in use, this question is merely a matter of curiosity. Alternate approaches to the wrapper classes are not relevant. Defining a method with a bunch of arguments taking Null default values is not correct (what if you define 20 arguments, but the function is called with 21?). Answers don't even need to be written in terms of MySQL_stmt_throwing; it exists simply to provide a concrete example.

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  • SQLDependency thread

    - by user171523
    i am in the process implementing SQLdepenency i would like to know in case of Dependency Handler exeuctues will it spun a different thred from main Process ? What will happen when the event handler triggers? Do i need to worry about any multithreds issues? public void CreateSqlDependency() { try { using (SqlConnection connection = (SqlConnection)DBFactory.GetDBFactoryConnection(Constants.SQL_PROVIDER_NAME)) { SqlCommand command = (SqlCommand)DBFactory.GetCommand(Constants.SQL_PROVIDER_NAME); command.CommandText = watchQuery; command.CommandType = CommandType.Text; SqlDependency dependency = new SqlDependency(command); //Create the callback object dependency.OnChange += new OnChangeEventHandler(this.QueueChangeNotificationHandler); SqlDependency.Start(connectionString); DataTable dataTable = DBFactory.ExecuteSPReDT(command); } } catch (SqlException sqlExp) { throw sqlExp; } catch (Exception ex) { throw ex; } } public void QueueChangeNotificationHandler(object caller, SqlNotificationEventArgs e) { if(e.Info == SqlNotificationInfo.Insert) Fire(); }

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  • To call SelectMany dynamically in the way of System.Linq.Dynamic

    - by user341127
    In System.Linq.Dynamic, there are a few methods to form Select, Where and other Linq statements dynamically. But there is no for SelectMany. The method for Select is as the following: public static IQueryable Select(this IQueryable source, string selector, params object[] values) { if (source == null) throw new ArgumentNullException("source"); if (selector == null) throw new ArgumentNullException("selector"); LambdaExpression lambda = DynamicExpression.ParseLambda(source.ElementType, null, selector, values); IQueryable result = source.Provider.CreateQuery( Expression.Call( typeof(Queryable), "Select", new Type[] { source.ElementType, lambda.Body.Type }, source.Expression, Expression.Quote(lambda))); return result; } I tried to modify the above code, after hours working, I couldn't find a way out. Any suggestions are welcome. Ying

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  • Generic List<T> as IEnumerable<object>

    - by Avi
    I'm trying to do cast a List to an IEnumerable, so I can verify that different lists are not null or empty: Suppose myList is a List < T . Then in the caller code I wanted: Validator.VerifyNotNullOrEmpty(myList as IEnumerable<object>, @"myList", @"ClassName.MethodName"); The valdiating code would be: public static void VerifyNotNullOrEmpty(IEnumerable<object> theIEnumerable, string theIEnumerableName, string theVerifyingPosition) { string errMsg = theVerifyingPosition + " " + theIEnumerableName; if (theIEnumerable == null) { errMsg += @" is null"; Debug.Assert(false); throw new ApplicationException(errMsg); } else if (theIEnumerable.Count() == 0) { errMsg += @" is empty"; Debug.Assert(false); throw new ApplicationException(errMsg); } } However, this doens't work. It compiles, but theIEnumerable is null! Why?

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  • Static analysis of multiple if statements (conditions)

    - by koppernickus
    I have code similar to: if conditionA(x, y, z) then doA() else if conditionB(x, y, z) then doB() ... else if conditionZ(x, y, z) then doZ() else throw ShouldNeverHappenException I would like to validate two things (using static analysis): If all conditions conditionA, conditionB, ..., conditionZ are mutually exclusive (i.e. it is not possible that two or more conditions are true in the same time). All possible cases are covered, i.e. "else throw" statement will never be called. Could you recommend me a tool and/or a way I could (easily) do this? I would appreciate more detailed informations than "use Prolog" or "use Mathematica"... ;-)

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  • I am getting exception in main thread...even when i am handling the exception

    - by fari
    public KalaGame(KeyBoardPlayer player1,KeyBoardPlayer player2) { //super(0); int key=0; try { do{ System.out.println("Enter the number of stones to play with: "); BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); key = Integer.parseInt(br.readLine()); if(key<0 || key>10) throw new InvalidStartingStonesException(key); } while(key<0 || key>10); player1=new KeyBoardPlayer(); player2 = new KeyBoardPlayer(); this.player1=player1; this.player2=player2; state=new KalaGameState(key); } catch(IOException e) { System.out.println(e); } } when i enter an invalid number of stones i get this error Exception in thread "main" InvalidStartingStonesException: The number of starting stones must be greater than 0 and less than or equal to 10 (attempted 22) why isn't the exception handled by the throw i defined at KalaGame.<init>(KalaGame.java:27) at PlayKala.main(PlayKala.java:10)

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  • Contracts vs Exceptions

    - by devoured elysium
    Let's assume I have the following code: public class MainClass { public static void main(String[] args) { System.out.println(sumNumbers(10, 10)); } //@requires a >= 10; //@ensures \result < 0; public static int sumNumbers(int a, int b) { return a+b; } } I can make 2 things here: Use Code Contracts (in this case, what is in comments). When sumNumbers is run and a < 10, it will throw immediatly an exception (although it doesn't seem to be very descriptive): Exception in thread "main" org.jmlspecs.jmlrac.runtime.JMLInternalNormalPostconditionError: by method MainClass.sumNumbers at MainClass.sumNumbers(MainClass.java:500) at MainClass.internal$main(MainClass.java:9) at MainClass.main(MainClass.java:286) or... Throw an exception. The exception can be as descriptive as I want. I'd also to check in the end of the function to see whenever the post conditions are true or not. Which would you use here and why?

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  • Perl equivalent to Java's "throws" clause

    - by Konerak
    Is there a way in Perl to declare that a method can throw an error (or die)? EDIT: What interests me the most is a way to get the compiler or IDE to tell me I have an unchecked exception somewhere in my code. I always loved how in Java, a method could handle an Exception and/or throw it. The method signature allows to put "throws MyException", so a good IDE/compiler would know that if you use said method somewhere in your code, you'd have to check for the Exception or declare your function to "throws" the Exception further. I'm unable to find something alike in Perl. A collegue of mine wrote a method which "dies" on incorrect input, but I forget to eval-if($@) it... offcourse the error was only discovered while a user was running the application. (offcourse I doubt if there is any existing IDE that could find these kind of things for Perl, but atleast perl -cw should be able to, no?)

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  • ASP.net MVC [HandleError] not catching exceptions.

    - by Eric
    In two different application, one a custom the other the sample MVC application you get with a new VS2008 MVC project, [HandleError] is not catching exceptions. In the sample application I have: [HandleError] public class HomeController : Controller { public ActionResult Index() { ViewData["Message"] = "Welcome to ASP.NET MVC!"; throw new Exception(); return View(); } public ActionResult About() { return View(); } } which is just the default controller with an exception being thrown for testing. But it doesn't work. Instead of going to the default error.aspx page it shows the debug information in the browser. The problem first cropped up in a custom application I'm working on which led me to test it with the sample application. Thinking it had something to do with changes I made in the custom application, I left the sample application completely unchanged with the exception (yuck) of the throw in the index method. I'm stumped. What am I missing?

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  • Remove a keyboard shortcut binding in Visual Studio using Macros

    - by Pete
    Hi. I have a lot of custom keyboard shortcuts set up. To avoid having to set them up every time I install a new visual studio (happens quite a lot currectly, with VS2010 being in beta/RC) I have created a macro, that sets up all my custom commands, like this: DTE.Commands.Item("ReSharper.ReSharper_UnitTest_RunSolution").Bindings = "Global::Ctrl+T, Ctrl+A" My main problem is that Ctrl+T is set up to map to the transpose char command by default. So I want to remove that default value in my macro. I have tried the following two lines, but both throw an exception DTE.Commands.Item("Edit.CharTranspose").Bindings = "" DTE.Commands.Item("Edit.CharTranspose").Bindings = Nothing Although they kind of work, because they actually remove the binding ;) But I would prefer the solution that doesn't throw an exception. How is that done?

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  • Can the Perl compiler tell me if I have an unchecked exception in my code?

    - by Konerak
    Is there a way in Perl to declare that a method can throw an error (or die)? EDIT: What interests me the most is a way to get the compiler or IDE to tell me I have an unchecked exception somewhere in my code. I always loved how in Java, a method could handle an Exception and/or throw it. The method signature allows to put "throws MyException", so a good IDE/compiler would know that if you use said method somewhere in your code, you'd have to check for the Exception or declare your function to "throws" the Exception further. I'm unable to find something alike in Perl. A collegue of mine wrote a method which "dies" on incorrect input, but I forget to eval-if($@) it... offcourse the error was only discovered while a user was running the application. (offcourse I doubt if there is any existing IDE that could find these kind of things for Perl, but atleast perl -cw should be able to, no?)

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