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  • Linq to SQL DynamicInvoke(System.Object[])' has no supported translation to SQL.

    - by ewwwyn
    I have a class, Users. Users has a UserId property. I have a method that looks something like this: static IQueryable<User> FilterById(this IQueryable<User> p, Func<int, bool> sel) { return p.Where(m => sel(m)); } Inevitably, when I call the function: var users = Users.FilterById(m => m > 10); I get the following exception: Method 'System.Object DynamicInvoke(System.Object[])' has no supported translation to SQL. Is there any solution to this problem? How far down the rabbit hole of Expression.KillMeAndMyFamily() might I have to go? To clarify why I'm doing this: I'm using T4 templates to autogenerate a simple repository and a system of pipes. Within the pipes, instead of writing: new UserPipe().Where(m => m.UserId > 10 && m.UserName.Contains("oo") && m.LastName == "Wee"); I'd like to generate something like: new UserPipe() .UserId(m => m > 10) .UserName(m => m.Contains("oo")) .LastName("Wee");

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  • Collision Attacks, Message Digests and a Possible solution

    - by Dominar
    I've been doing some preliminary research in the area of message digests. Specifically collision attacks of cryptographic hash functions such as MD5 and SHA-1, such as the Postscript example and X.509 certificate duplicate. From what I can tell in the case of the postscript attack, specific data was generated and embedded within the header of the postscript (which is ignored during rendering) which brought about the internal state of the md5 to a state such that the modified wording of the document would lead to a final MD equivalent to the original. The X.509 took a similar approach where by data was injected within the comment/whitespace of the certificate. Ok so here is my question, and I can't seem to find anyone asking this question: Why isn't the length of ONLY the data being consumed added as a final block to the MD calculation? In the case of X.509 - Why is the whitespace and comments being taken into account as part of the MD? Wouldn't a simple processes such as one of the following be enough to resolve the proposed collision attacks: MD(M + |M|) = xyz MD(M + |M| + |M| * magicseed_0 +...+ |M| * magicseed_n) = xyz where : M : is the message |M| : size of the message MD : is the message digest function (eg: md5, sha, whirlpool etc) xyz : is the acutal message digest value for the message M magicseed_{i}: Is a set random values generated with seed based on the internal-state prior to the size being added. This technqiue should work, as to date all such collision attacks rely on adding more data to the original message. In short, the level of difficulty involved in generating a collision message such that: It not only generates the same MD But is also comprehensible/parsible/compliant and is also the same size as the original message, is immensely difficult if not near impossible. Has this approach ever been discussed? Any links to papers etc would be nice.

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  • 3 dimensional bin packing algorithms

    - by BuschnicK
    I'm faced with a 3 dimensional bin packing problem and am currently conducting some preliminary research as to which algorithms/heuristics are currently yielding the best results. Since the problem is NP hard I do not expect to find the optimal solution in every case, but I was wondering: 1) what are the best exact solvers? Branch and Bound? What problem instance sizes can I expect to solve with reasonable computing resources? 2) what are the best heuristic solvers? 3) What off-the-shelf solutions exist to conduct some experiments with?

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  • Regex to represent "NOT" in a group

    - by Joe Ijam
    I have this Regex; <(\d+)(\w+\s\d+\s\d+(?::\d+){2})\s([\w\/.-])(.) What I want to do is to return FALSE(Not matched) if the third group is "MSWinEventLog" and returning "matched" for the rest. <166Apr 28 10:46:34 AMC the remaining phrase <11Apr 28 10:46:34 MSWinEventLog the remaining phrase <170Apr 28 10:46:34 Avantail the remaining phrase <171Apr 28 10:46:34 Avantail the remaining phrase <172Apr 28 10:46:34 AMC the remaining phrase <173Apr 28 10:46:34 AMC the remaining phrase <174Apr 28 10:46:34 Avantail the remaining phrase <175Apr 28 10:46:34 AMC the remaining phrase <176Apr 28 10:46:34 AMC the remaining phrase <177Apr 28 10:46:34 Avantail the remaining phrase <178Apr 28 10:46:34 AMC the remaining phrase <179Apr 28 10:46:34 Avantail the remaining phrase <180Apr 28 10:46:34 Avantail the remaining phrase How to put " NOT 'MSWinEventLog' " in the regex group ([\w\/.-]*) ? Note : The second phrase above should return "not matched"

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  • How do you unit test a LINQ expression using Moq and Machine.Specifications?

    - by Phil.Wheeler
    I'm struggling to get my head around how to accommodate a mocked repository's method that only accepts a Linq expression as its argument. Specifically, the repository has a First() method that looks like this: public T First(Expression<Func<T, bool>> expression) { return All().Where(expression).FirstOrDefault(); } The difficulty I'm encountering is with my MSpec tests, where I'm (probably incorrectly) trying to mock that call: public abstract class with_userprofile_repository { protected static Mock<IRepository<UserProfile>> repository; Establish context = () => { repository = new Mock<IRepository<UserProfile>>(); repository.Setup<UserProfile>(x => x.First(up => up.OpenID == @"http://testuser.myopenid.com")).Returns(GetDummyUser()); }; protected static UserProfile GetDummyUser() { UserProfile p = new UserProfile(); p.OpenID = @"http://testuser.myopenid.com"; p.FirstName = "Joe"; p.LastLogin = DateTime.Now.Date.AddDays(-7); p.LastName = "Bloggs"; p.Email = "[email protected]"; return p; } } I run into trouble because it's not enjoying the Linq expression: System.NotSupportedException: Expression up = (up.OpenID = "http://testuser.myopenid.com") is not supported. So how does one test these sorts of scenarios?

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  • Using linq to combine objects

    - by DotnetDude
    I have 2 instances of a class that implements the IEnumerable interface. I would like to create a new object and combine both of them into one. I understand I can use the for..each to do this. Is there a linq/lambda expression way of doing this?

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  • Having trouble with Regular Expression and Ampersand

    - by ajax81
    Hi All, I'm having a bit of trouble with regex's (C#, ASP.NET), and I'm pretty sure I'm doing something fundamentally wrong. My task is to bind a dynamically created gridview to a datasource, and then iterate through a column in the grid, looking for the string "A&I". An example of what the data in the cell (in template column) looks like is: Name: John Doe Phone: 555-123-1234 Email: [email protected] Dept: DHS-A&I-MRB Here's the code I'm using to find the string value: foreach(GridViewRow gvrow in gv.Rows) { Match m = Regex.Match(gvrow.Cells[6].Text,"A&I"); if(m.Success) { gvrow.ForeColor = System.Drawing.Color.Red; } } I'm not having any luck with any of these variations: "A&I" "[A][&][I]" But when I strictly user "&", the row does turn red. Any suggestions? Thanks, Dan

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  • Regular expression help

    - by DJPB
    I there I'm working on a C# app, and I get a string with a date or part of a date and i need to take day, month and year for that string ex: string example='31-12-2010' string day = Regex.Match(example, "REGULAR EXPRESSION FOR DAY").ToString(); string month = Regex.Match(example, "REGULAR EXPRESSION FOR MONTH").ToString() string year = Regex.Match(example, "REGULAR EXPRESSION FOR YEAR").ToString() day = "31" month = "12" year = "2010" ex2: string example='12-2010' string month = Regex.Match(example, "REGULAR EXPRESSION FOR MONTH").ToString() string year = Regex.Match(example, "REGULAR EXPRESSION FOR YEAR").ToString() month = "12" year = "2010" any idea? tks

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  • Is there any free Equation Editor Control

    - by troy
    Hi am going to do some project there i need to show integral , sigma, pie , etc.. so is there any equation edtior controls available. so I have to integrate to my Asp.Net project I got one editor ie: LAtex Equation editor but it show the html format in the textbox ,and also it show his site name etc on the Equation popup editor, it not free at all. Any idea pls..

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  • Best open source Mixed Integer Optimization Solver

    - by Mark
    I am using CPLEX for solving huge optimization models (more than 100k variables) now I'd like to see if I can find an open source alternative, I solve mixed integer problems (MILP) and CPLEX works great but it is very expensive if we want to scale so I really need to find an alternative or start writing our own ad-hoc optimization library (which will be painful) Any suggestion/insight would be much appreciated

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  • Problem in populating a dictionary using Enumerable.Range()

    - by Newbie
    If I do for (int i = 0; i < appSettings.Count; i++) { string key = appSettings.Keys[i]; euFileDictionary.Add(key, appSettings[i]); } It is working fine. When I am trying the same thing using Enumerable.Range(0, appSettings.Count).Select(i => { string Key = appSettings.Keys[i]; string Value = appSettings[i]; euFileDictionary.Add(Key, Value); }).ToDictionary<string,string>(); I am getting a compile time error The type arguments for method 'System.Linq.Enumerable.Select(System.Collections.Generic.IEnumerable, System.Func)' cannot be inferred from the usage. Try specifying the type arguments explicitly. Any idea? Using C#3.0 Thanks

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  • Rendering LaTeX on third-party websites

    - by A. Rex
    There are some sites on the web that render LaTeX into some more readable form, such as Wikipedia, some Wordpress blogs, and MathOverflow. They may use images, MathML, jsMath, or something like that. There are other sites on the web where LaTeX appears inline and is not rendered, such as the arXiv, various math forums, or my email. In fact, it is quite common to see an arXiv paper's abstract with raw LaTeX in it, e.g. this paper. Is there a plugin available for Firefox, or would it be possible to write one, that renders LaTeX within pages that do not provide a rendering mechanism themselves? Some notes: It may be impossible to render some of the code, because authors often copy-paste code directly from their source TeX files, which may contain things like "\cite{foo}" or undefined commands. These should be left alone. This question is a repost of a question from MathOverflow that was closed for not being related to math. I program a lot, but Javascript is not my specialty, so comments along the lines of "look at this library" are not particularly helpful to me (but may be to others).

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  • RegularExpression Validator doesn't display error message.

    - by Rudi Ramey
    I have a regular expression validation control initialized to validate a textbox control. I want users to be able to enter U.S. Currency values ($12,115.85 or 1500.22 etc.). I found a regular expression off of regexlib website that does the trick. The validation control seems to be working except for one crucial thing. If invalid data is entered, the validation text dispalys (a red "*" next to the textbox), but the page will still submit and the error message won't pop up... I thought that the error message is supposed to display and the page won't submit if the validation control detects invalid data. Isn't this automatic with ASP .NET? I have searched extensively on how to create validation controls, but haven't found anything different than what I am already doing. Can anyone tell me what I am doing wrong here? <asp:TextBox ID="txtActualCost" runat="server" Width="120px" CausesValidation="true"></asp:TextBox> <asp:RegularExpressionValidator ID="regExValActualCost" ControlToValidate="txtActualCost" Text="*" ValidationExpression="^\$?(\d{1,3}(\,\d{3})*|(\d+))(\.\d{2})?$" ErrorMessage="Please enter a valid currency value for 'Actual Cost'" Display="Dynamic" EnableClientScript="true" runat="server" />

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  • Func<sometype,bool> to Func<T,bool>

    - by user175528
    If i have: public static Func<SomeType, bool> GetQuery() { return a => a.Foo=="Bar"; } and a generic version public static Func<T, bool> GetQuery<T>() { return (Func<T,bool>)GetQuery(); } how can I do the case? The only way I have found so far is to try and combine it with a mock function: Func<T, bool> q=a => true; return (Func<T, bool>)Delegate.Combine(GetQuery(), q); I know how to do that with Expression.Lambda, but I need to work with plain functions, not expression trees

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  • How do you unit test a method containing a LINQ expression?

    - by Phil.Wheeler
    I'm struggling to get my head around how to accommodate a mocked method that only accepts a Linq expression as its argument. Specifically, the repository I'm using has a First() method that looks like this: public T First(Expression<Func<T, bool>> expression) { return All().Where(expression).FirstOrDefault(); } The difficulty I'm encountering is with my MSpec tests, where I'm (probably incorrectly) trying to mock that call: public abstract class with_userprofile_repository { protected static Mock<IRepository<UserProfile>> repository; Establish context = () => { repository = new Mock<IRepository<UserProfile>>(); repository.Setup<UserProfile>(x => x.First(up => up.OpenID == @"http://testuser.myopenid.com")).Returns(GetDummyUser()); }; protected static UserProfile GetDummyUser() { UserProfile p = new UserProfile(); p.OpenID = @"http://testuser.myopenid.com"; p.FirstName = "Joe"; p.LastLogin = DateTime.Now.Date.AddDays(-7); p.LastName = "Bloggs"; p.Email = "[email protected]"; return p; } } I run into trouble because it's not enjoying the Linq expression: System.NotSupportedException: Expression up = (up.OpenID = "http://testuser.myopenid.com") is not supported. So how does one test these sorts of scenarios?

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  • Optimizing mathematics on arrays of floats in Ada 95 with GNATC

    - by mat_geek
    Consider the bellow code. This code is supposed to be processing data at a fixed rate, in one second batches, It is part of an overal system and can't take up too much time. When running over 100 lots of 1 seconds worth of data the program takes 35 seconds; or 35%. How do I improce the code to get the processing time down to a minimum? The code will be running on an Intel Pentium-M which is a P3 with SSE2. package FF is new Ada.Numerics.Generic_Elementary_Functions(Float); N : constant Integer := 820; type A is array(1 .. N) of Float; type A3 is array(1 .. 3) of A; procedure F(state : in out A3; result : out A3; l : in A; r : in A) is s : Float; t : Float; begin for i in 1 .. N loop t := l(i) + r(i); t := t / 2.0; state(1)(i) := t; state(2)(i) := t * 0.25 + state(2)(i) * 0.75; state(3)(i) := t * 1.0 /64.0 + state(2)(i) * 63.0 /64.0; for r in 1 .. 3 loop s := state(r)(i); t := FF."**"(s, 6.0) + 14.0; if t > MAX then t := MAX; elsif t < MIN then t := MIN; end if; result(r)(i) := FF.Log(t, 2.0); end loop; end loop; end;

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  • OSLO, ANTLR or other parser grammar, for parsing QUERY EXPRESSION

    - by Jay Allard
    Greetings I'm working on a project that requires me to write queries in text form, then convert them to some easily processed nodes to be processed by some abiguous repository. Of everything there, the part I'm least interested is the part that converts the text to nodes. I'm hoping it's already done somewhere. Because I'm making stuff up as I go, I chose to use a LINQish expression syntax. from m in Movie select m.A, m.B I started parsing it manually and got the basics, but it's pretty cheesy. I'm looking for the better solution. I made some progress using MGrammar, but it would be nice if such a thing already existed. Does anyone know of anything that already does this? I looked for existing ANTLR templates, but no luck. Thanks for the help.

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  • How can I make this work with deep properties

    - by Martin Robins
    Given the following code... class Program { static void Main(string[] args) { Foo foo = new Foo { Bar = new Bar { Name = "Martin" }, Name = "Martin" }; DoLambdaStuff(foo, f => f.Name); DoLambdaStuff(foo, f => f.Bar.Name); } static void DoLambdaStuff<TObject, TValue>(TObject obj, Expression<Func<TObject, TValue>> expression) { // Set up and test "getter"... Func<TObject, TValue> getValue = expression.Compile(); TValue stuff = getValue(obj); // Set up and test "setter"... ParameterExpression objectParameterExpression = Expression.Parameter(typeof(TObject)), valueParameterExpression = Expression.Parameter(typeof(TValue)); Expression<Action<TObject, TValue>> setValueExpression = Expression.Lambda<Action<TObject, TValue>>( Expression.Block( Expression.Assign(Expression.Property(objectParameterExpression, ((MemberExpression)expression.Body).Member.Name), valueParameterExpression) ), objectParameterExpression, valueParameterExpression ); Action<TObject, TValue> setValue = setValueExpression.Compile(); setValue(obj, stuff); } } class Foo { public Bar Bar { get; set; } public string Name { get; set; } } class Bar { public string Name { get; set; } } The call to DoLambdaStuff(foo, f => f.Name) works ok because I am accessing a shallow property, however the call to DoLambdaStuff(foo, f => f.Bar.Name) fails - although the creation of the getValue function works fine, the creation of the setValueExpression fails because I am attempting to access a deep property of the object. Can anybody please help me to modify this so that I can create the setValueExpression for deep properties as well as shallow? Thanks.

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  • Dynamic Linq Property Converting to Sql

    - by Matthew Hood
    I am trying to understand dynamic linq and expression trees. Very basically trying to do an equals supplying the column and value as strings. Here is what I have so far private IQueryable<tblTest> filterTest(string column, string value) { TestDataContext db = new TestDataContext(); // The IQueryable data to query. IQueryable<tblTest> queryableData = db.tblTests.AsQueryable(); // Compose the expression tree that represents the parameter to the predicate. ParameterExpression pe = Expression.Parameter(typeof(tblTest), "item"); Expression left = Expression.Property(pe, column); Expression right = Expression.Constant(value); Expression e1 = Expression.Equal(left, right); MethodCallExpression whereCallExpression = Expression.Call( typeof(Queryable), "Where", new Type[] { queryableData.ElementType }, queryableData.Expression, Expression.Lambda<Func<tblTest, bool>>(e1, new ParameterExpression[] { pe })); // Create an executable query from the expression tree. IQueryable<tblTest> results = queryableData.Provider.CreateQuery<tblTest>(whereCallExpression); return results; } That works fine for columns in the DB. But fails for properties in my code eg public partial class tblTest { public string name_test { get { return name; } } } Giving an error cannot be that it cannot be converted into SQL. I have tried rewriting the property as a Expression<Func but with no luck, how can I convert simple properties so they can be used with linq in this dynamic way? Many Thanks

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  • String replacement in PHP

    - by [email protected]
    This is my first question on this wonderful website. Lets say I have a string $a="some text..%PROD% more text" There will be just one %..% in the string. I need to replace PROD between the % with another variable content. So I used to do: $a = str_replace('%PROD%',$var,$a); but now the PROD between % started coming in different cases. So I could expect prod or Prod. So I made the entire string uppercase before doing replacement. But the side effect is that other letters in the original string also became uppercase. Someone suggested me to use regular expression. But how ? Thanks, Rohan

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  • other way to add item do List<>

    - by netmajor
    In my other ask You can see code of my arr structure and PriorityQueue collection. I normally add items to this collection like that: arr.PriorityQueue.Add(new element((value(item, endPoint) + value(startPoint, item)),item)); I am curious that is other way to do this (add element(which is struct) object to List) ? In lambda way for example ? I just eager for knowledge :)

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  • .NET Lambda Pass Method Parameter

    - by RM
    Hi All, I hope i'm missing something obvious, but I'm having some troubles defining a method that takes a parameter of a method to fetch the method information for the passed method. I do NOT want actually execute the method. I want to be able to do: busObject.SetResolverMethod<ISomeInterface>(x=>x.GetNameById); Where GetNameById is a method defined on the interface ISomeInterface. In this case, an example of the method being passed in's signature would be: MyVarA GetNameById(int id){ .... } In the above example, the SetResolverMethod's body should be able to return / store the string "GetNameById". There is no standard signature the method being passed in will conform to (except that it will always return an object of some kind). Currently I'm setting the method as a string (i.e. "GetNameById"), but I want it to be compile time checked, hence this question.

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