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  • SOAP call with query on result (SSRS, Sharepoint)

    - by Erik404
    Hi! I created a report in VS using a shared data source which is connected to a sharepoint list. In the report I created a dataset with a SOAP call to the data source so I get the result from the sharepoint list in a table. this is the soap call <Query> <SoapAction>http://schemas.microsoft.com/sharepoint/soap/GetListItems</SoapAction> <Method Namespace="http://schemas.microsoft.com/sharepoint/soap/" Name="GetListItems"> <Parameters> <Parameter Name="listName"> <DefaultValue>{BD8D39B7-FA0B-491D-AC6F-EC9B0978E0CE}</DefaultValue> </Parameter> <Parameter Name="viewName"> <DefaultValue>{E2168426-804F-4836-9BE4-DC5F8D08A54F}</DefaultValue> </Parameter> <Parameter Name="rowLimit"> <DefaultValue>9999</DefaultValue> </Parameter> </Parameters> </Method> <ElementPath IgnoreNamespaces="True">*</ElementPath> </Query> THis works fine, I have a result which I can show in a report, but I want to have the ability to select a parameter to filter the result on. I have created a parameter and when I preview the Report I see the dropdownbox which I can use to make a selection from the Title field, when I do this it still shows the first record, obviously it doens't work yet (DUH!) because I need to create a query somewhere, But! I have no idea where, I tried to include <Where> <Eq> <FieldRef Name="ows_Title" /> <Value Type="Text">testValue</Value> </Eq> </Where> in the the soap request but it didn't worked... I've searched teh intarwebz but couldn't find any simliar problems... kinda stuck now...any thoughts on this? EDIT Here's the query I used according to the blogpost Alex Angas linked. <Query> <SoapAction>http://schemas.microsoft.com/sharepoint/soap/GetListItems</SoapAction> <Method Namespace="http://schemas.microsoft.com/sharepoint/soap/" Name="GetListItems"> <queryOptions></queryOptions> <query><Query> <Where> <Eq> <FieldRef Name="ows_Title"/> <Value Type="Text">someValue</Value> </Eq> </Where> </Query></query> <Parameters> <Parameter Name="listName"> <DefaultValue>{BD8D39B7-FA0B-491D-AC6F-EC9B0978E0CE}</DefaultValue> </Parameter> <Parameter Name="viewName"> <DefaultValue>{E2168426-804F-4836-9BE4-DC5F8D08A54F}</DefaultValue> </Parameter> <Parameter Name="rowLimit"> <DefaultValue>9999</DefaultValue> </Parameter> </Parameters> </Method> <ElementPath IgnoreNamespaces="True">*</ElementPath> </Query> I tried to put the new query statement in every possible way in the existing, but it doesn't work at all, I do not get an error though so the code is valid, but I still get an unfiltered list as return... pulling my hair out here!

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  • Visual Studio Talk Show #118 is now online - Command-Query Responsibility Separation (French)

    http://www.visualstudiotalkshow.com Erik Renaud: La sparation des responsabilits entre les commandes et les requtes Nous discutons avec Erik Renaud de la sparation des responsabilits entre les commandes et les requtes (Command-Query Responsibility Separation - CQRS). La plupart des applications lisent les donnes beaucoup plus frquemment qu'ils font des critures. Sur la base de cette dclaration, une bonne ide consiste sparer le code qui est responsable de lcriture des donnes du code qui est...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Removing Duplicate Data From SQL Query Output For Display On A Web Page [migrated]

    - by doubleJ
    I had asked a similar question on stackoverflow but didn't really get anywhere. This page shows the output that I'm currently getting from my MSSQL server. I have a table of venue information (name, address, etc...) that our events happen on. Separately, I have a table of the actual events that are scheduled (an event may happen multiple times in one day and/or over multiple days). I join those tables with this query: <?php try { $dbh = new PDO("sqlsrv:Server=localhost;Database=Sermons", "", ""); $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); $sql = "SELECT TOP (100) PERCENT dbo.TblSermon.Day, dbo.TblSermon.Date, dbo.TblSermon.Time, dbo.TblSermon.Speaker, dbo.TblSermon.Series, dbo.TblSermon.Sarasota, dbo.TblSermon.NonFlc, dbo.TblJoinSermonLocation.MeetingName, dbo.TblLocation.Location, dbo.TblLocation.Pastors, dbo.TblLocation.Address, dbo.TblLocation.City, dbo.TblLocation.State, dbo.TblLocation.Zip, dbo.TblLocation.Country, dbo.TblLocation.Phone, dbo.TblLocation.Email, dbo.TblLocation.WebAddress FROM dbo.TblLocation RIGHT OUTER JOIN dbo.TblJoinSermonLocation ON dbo.TblLocation.ID = dbo.TblJoinSermonLocation.Location RIGHT OUTER JOIN dbo.TblSermon ON dbo.TblJoinSermonLocation.Sermon = dbo.TblSermon.ID WHERE (dbo.TblSermon.Date >= { fn NOW() }) ORDER BY dbo.TblSermon.Date, dbo.TblSermon.Time"; $stmt = $dbh->prepare($sql); $stmt->execute(); $stmt->setFetchMode(PDO::FETCH_ASSOC); foreach ($stmt as $row) { echo "<pre>"; print_r($row); echo "</pre>"; } unset($row); $dbh = null; } catch(PDOException $e) { echo $e->getMessage(); } ?> So, as it loops through the query results, it creates an array for each record and ends up like this: Array ( [Day] => Tuesday [Date] => 2012-10-30 00:00:00.000 [Time] => 07:00 PM [Speaker] => Keith Moore [Location] => The Ark Church [Pastors] => Alan & Joy Clayton [Address] => 450 Humble Tank Rd. [City] => Conroe [State] => TX [Zip] => 77305.0 [Phone] => (936) 756-1988 [Email] => [email protected] [WebAddress] => http://www.thearkchurch.org ) Array ( [Day] => Wednesday [Date] => 2012-10-31 00:00:00.000 [Time] => 07:00 PM [Speaker] => Keith Moore [Location] => The Ark Church [Pastors] => Alan & Joy Clayton [Address] => 450 Humble Tank Rd. [City] => Conroe [State] => TX [Zip] => 77305.0 [Phone] => (936) 756-1988 [Email] => [email protected] [WebAddress] => http://www.thearkchurch.org ) Array ( [Day] => Tuesday [Date] => 2012-11-06 00:00:00.000 [Time] => 07:00 PM [Speaker] => Keith Moore [Location] => Fellowship Of Faith Christian Center [Pastors] => Michael & Joan Kalstrup [Address] => 18999 Hwy. 59 [City] => Oakland [State] => IA [Zip] => 51560.0 [Phone] => (712) 482-3455 [Email] => [email protected] [WebAddress] => http://www.fellowshipoffaith.cc ) Array ( [Day] => Wednesday [Date] => 2012-11-14 00:00:00.000 [Time] => 07:00 PM [Speaker] => Keith Moore [Location] => Faith Family Church [Pastors] => Michael & Barbara Cameneti [Address] => 8200 Freedom Ave NW [City] => Canton [State] => OH [Zip] => 44720.0 [Phone] => (330) 492-0925 [Email] => [WebAddress] => http://www.myfaithfamily.com ) As you can see, The Ark Church and its associated contact information is duplicated, so when I work with those arrays and output them to the page, I see a bunch of duplicate content. I'd like to remove the duplicate information so that I get results similar to this: The Ark Church Alan & Joy Clayton 450 Humble Tank Rd. Conroe, TX 77305 (936) 756-1988 [email protected] http://www.thearkchurch.org Meetings: Tuesday, 2012-10-30 07:00 PM Wednesday, 2012-10-31 07:00 PM Fellowship Of Faith Christian Center Michael & Joan Kalstrup 18999 Hwy. 59 Oakland, IA 51560 (712) 482-3455 [email protected] http://www.fellowshipoffaith.cc Meetings: Tuesday, 2012-11-06 07:00 PM Faith Family Church Michael & Barbara Cameneti 8200 Freedom Ave NW Canton, OH 44720 (330) 492-0925 http://www.myfaithfamily.com Meetings: Wednesday, 2012-11-14 07:00 PM It doesn't necessarily have to end up like that (I'm not looking for code specific for these results, but a concept of how to not show the duplicated information). I'm assuming that an additional foreach or while will do it, but I haven't figured out any logic that says <?php if ($location == $previouslocation) echo ""; ?>.

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  • Performance Tuning and Query Optimisation–SQLBits Training Day

    - by simonsabin
    I will be doing a training day at SQLbits in April on Performance Tuning and Query Optimisation. This is the outline for the day. Its going to be an intense day, I look forward to seeing you there. To register go to http://www. sqlbits .com/information/registration.aspx . Places are limited so make sure you register soon. Outline of the day. Most database performance issues are due to a combination of bad queries, bad database design or poor indexing. All of them are related to each other. In this...(read more)

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  • How to deal with transactions when creating a database connection for each query

    - by webnoob
    In line with this post here I am going to change my website to create a connection per query to take advantage of .NET's connection pooling. With this in mind, I don't know how I should deal with transactions. At the moment I do something like (psuedo code): GlobalTransaction = GlobalDBConnection.BeginTransaction(); try { ExecSQL("insert into table ..") ExecSQL("update some_table ..") .... GlobalTransaction.Commit(); }catch{ GlobalTransaction.Rollback(); throw; } ExecSQL would be like this: using (SqlCommand Command = GlobalDBConnection.CreateCommand()) { Command.Connection = GlobalDBConnection; Command.Transaction = GlobalTransaction; Command.CommandText = SQLStr; Command.ExecuteNonQuery(); } I'm not quite sure how to change this concept to deal with transactions if the connection is created within ExecSQL because I would want the transaction to be shared between both the insert and update routines.

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  • A Christmas Query

    - by Gilles Haro
    Let’s celebrate Christmas with this absolutely useless query ! with Mx as (select 60 as MaxWidth from dual) select decode          ( sign(floor(MaxWidth /2)-rownum)          , 1          , lpad( ' ', floor(MaxWidth /2)-(rownum-1)) || rpad( '*', 2*(rownum-1)+1, ' *')          , lpad( '* * *', floor(MaxWidth/2)+3)         )    from all_tables, Mx  where rownum < floor(MaxWidth /2) + 6; Merry Christmas !   Gilles Haro Technical Expert - Core Technology, Oracle Consulting

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  • The orientation media query

    Right now Jason Grigby’s excellent summary of the orientation media query is making the round of blogs and tweets, and that’s well deserved. Media queries will become extremely important in the near future, when we have to build websites that work on any device resolution from 300px to 1280px or more.Still, there’s one tiny nitpick I’d like to make, so that you fully understand when to use orientation and when to use device-width.orientation is supported by Android 2, Bolt, MicroB, and Firefox. And...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • GA tracking utm query params after hashbang

    - by hybrid9
    We currently use a hashbang for the portion of our site that generates dynamic content which can also be deep linked. Our analytics team wants to use utm params to track the referral traffic from social networks. We are using Universal Analytics (analytics.js) as well as GTM. Will GA pick up the query parameters after the hashbang or does it always have to go before? For example: example.com/#!/some/content?utm_source=foo&utm_campaign=bar example.com?utm_source=foo&utm_campaign=bar/#!/some/content In #1, I'm concerned that the utm params won't be recorded and in #2 the page will break or the url could be incorrectly written. How does GA pull in those parameters - location.search? regex? Can I get away with using either?

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  • SQLAuthority News Microsoft SQL Server 2005/2008 Query Optimization & Performance Tuning Training

    Last 3 days to register for the courses. This is one time offer with big discount. The deadline for the course registration is 5th May, 2010. There are two different courses are offered by Solid Quality Mentors 1) Microsoft SQL Server 2005/2008 Query Optimization & Performance Tuning – Pinal Dave Date: May 12-14, 2010 Price: [...]...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Can I make query strings produce separate pages?

    - by John Smith
    I have a profile page with a URL like so: localhost/profile.php/?username=Bob I was wondering, if I had a separate <title> which changed according to the username, would they produce separate pages in the google search results? How do I tell Google to only use the username string or does it search within the title? On a similar note, how would I create a separate page with the username like so: localhost/bob instead of a query string like facebook does. Do that make a new file for each user?

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  • Cannot Install mysql-query-browser in Ubuntu 12.04

    - by doy
    Please help..... I tried to install mysql-query-browser in my Ubuntu 12.04 GUI, I get the error message: Updating mysql-administrator installation paths... ./mysql-administrator: 59: ./mysql-administrator: cannot create /opt/mysql-gui-tools-5.0/lib/pangorc.bak: Permission denied Error updating files for new installation path. Please make sure mysql-administrator is installed correctly and you have proper write permissions in the installation directory. Tried the ..... /opt/mysql-gui-tools-5.0$ ./mysql-administrator --update-paths . and /opt/mysql-gui-tools-5.0$ ./mysql-administrator --update-paths but still no success.........

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  • Search Engine Query Word Order

    - by EoghanM
    I've pages with titles like 'Alpha with Beta'. For every such page, there is an inverse page 'Beta with Alpha'. Both pages link to each other. When someone on Google searches for 'Beta with Alpha', I'd like them to land on the correct page, but sometimes 'Alpha with Beta' ranks higher (or vice versa). I was thinking of inspecting the referral link when a visitor arrives on my site, and silently redirecting them to the correct page based on what they actually searched for. Just wondering if this could be penalized by Google as 'cloaking/sneaky redirects'? Or is there a better way to ensure that the correct page on my site ranks higher for the matching query?

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  • SQL SERVER Get Latest SQL Query for Sessions DMV

    In recent SQL Training I was asked, how can one figure out what was the last SQL Statement executed in sessions. The query for this is very simple. It uses two DMVs and created following quick script for the same. SELECT session_id, TEXT FROM sys.dm_exec_connections CROSS APPLYsys.dm_exec_sql_text(most_recent_sql_handle) AS ST While working with DMVs if you [...]...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Using UNION in a query with PHP [migrated]

    - by work
    I have an SQL query which links 3 tables using UNION: $sql ="(SELECT Drive.DriveID,Ram.Memory from Drive,Ram where Drive.DriveID = Ram.RamID) UNION (SELECT Drive.DriveID,External.Memory from Drive, External where Drive.DriveID = External.ExtID)"; Suppose I want to get Ram.Name as well. How do I do this? If I use Ram.Name in the first SELECT statement it would not produce the correct result. Any method for tackling this? I want to do it using UNION.

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  • Learning MySQL Query optimization

    - by recluze
    I've been doing web/desktop/server development for a while and have worked with many databases (mysql mostly). I've come to the point in my career when I need to have someone look at my queries because they're 'kind of slow'. I believe it's now time to start learning query optimization. While I know the basics of index and joins etc., I'm not familiar with how to use, say, the EXPLAIN output to improve performance of my queries. I have not been able to find any online material that starts with the basics and takes me to application. Getting a book is not an option right now so I'm looking for tips about how to proceed with this. I hope this question is general enough not to get closed.

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  • lambda expression based reflection vs normal reflection

    - by bitbonk
    What is the difference between normal reflection and the reflection that can be done with lambda expressions such as this (taken form build your own MVVM): public void NotifyOfPropertyChange<TProperty>(Expression<Func<TProperty>> property) { var lambda = (LambdaExpression)property; MemberExpression memberExpression; if (lambda.Body is UnaryExpression) { var unaryExpression = (UnaryExpression)lambda.Body; memberExpression = (MemberExpression)unaryExpression.Operand; } else memberExpression = (MemberExpression)lambda.Body; NotifyOfPropertyChange(memberExpression.Member.Name); } Is the lambda based reflection just using the normal reflection APIs internally? Or is this something significantly different. What is ther perfomance difference?

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  • Lambda Contains in SimpleRepository.Find

    - by Anton
    In SubSonic 3.04's SimpleRepository, I cannot seem to perform a Contains operation within a lambda expression. Here's a trivial example: SimpleRepository repo = new SimpleRepository("ConnectionString"); List<int> userIds = new List<int>(); userIds.Add(1); userIds.Add(3); List<User> users = repo.Find<User>(x => userIds.Contains(x.Id)).ToList(); I get the error message: variable 'x' of type 'User' referenced from scope '', but it is not defined Am I missing something here, or does SubSonic not support Contains in lambda expressions? If not, how would this be done?

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  • Splitting a string according to a delimiter when elements in the string can contain the delimiter

    - by Vivin Paliath
    I have a string that looks like this: "#Text() #SomeMoreText() #TextThatContainsDelimiter(#blah) #SomethingElse()" I'd like to get back [#Text(), #SomeMoreText(), #TextThatContainsDelimiter(#blah), #SomethingElse()] One way I thought about doing this was to require that the # to be escaped into \#, which makes the input string: "#Text() #SomeMoreText() #TextThatContainsDelimiter(\#blah) #SomethingElse()" I can then split it using /[^\\]#/ which gives me: [#Text(), SomeMoreText, TextThatContainsDelimiter(\#blah), SomethingElse()] The first element will contain # but I can strip it out. However, is there a cleaner way to do this without having to escape the #, and which ensures that the first element will not contain a #? Basically I'd like it to split by # only if the # is not enclosed by parentheses. My hunch is that since the # is context-sensitive and and regular expressions are only suited for context-free strings, this may not be the right tool. If so, would I have to write a grammar for this and roll my own parser/lexer?

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  • How can I combine sequential expression trees into a fast method?

    - by chillitom
    Suppose I have the following expressions: Expression<Action<T, StringBuilder>> expr1 = (t, sb) => sb.Append(t.Name); Expression<Action<T, StringBuilder>> expr2 = (t, sb) => sb.Append(", "); Expression<Action<T, StringBuilder>> expr3 = (t, sb) => sb.Append(t.Description); I'd like to be able to compile these into a method/delegate equivalent to the following: void Method(T t, StringBuilder sb) { sb.Append(t.Name); sb.Append(", "); sb.Append(t.Description); } What is the best way to approach this? I'd like it to perform well, ideally with performance equivalent to the above method.

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  • C# Lambda Expression Speed

    - by Nathan
    I have not used many lambda expressions before and I ran into a case where I thought I could make slick use of one. I have a custom list of ~19,000 records and I need to find out if a record exists or not in the list so instead of writing a bunch of loops or using linq to go through the list I decided to try this: for (int i = MinX; i <= MaxX; ++i) { tempY = MinY; while (tempY <= MaxY) { bool exists = myList.Exists(item => item.XCoord == i && item.YCoord == tempY); ++tempY; } } Only problem is it take ~9 - 11 seconds to execute. Am I doing something wrong is this just a case of where I shouldn't be using an expression like this? Thanks.

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  • Mutating the expression tree of a predicate to target another type

    - by Jon
    Intro In the application I 'm currently working on, there are two kinds of each business object: the "ActiveRecord" type, and the "DataContract" type. So for example, we have: namespace ActiveRecord { class Widget { public int Id { get; set; } } } namespace DataContracts { class Widget { public int Id { get; set; } } } The database access layer takes care of "translating" between hierarchies: you can tell it to update a DataContracts.Widget, and it will magically create an ActiveRecord.Widget with the same property values and save that. The problem I have surfaced when attempting to refactor this database access layer. The Problem I want to add methods like the following to the database access layer: // Widget is DataContract.Widget interface DbAccessLayer { IEnumerable<Widget> GetMany(Expression<Func<Widget, bool>> predicate); } The above is a simple general-use "get" method with custom predicate. The only point of interest is that I 'm not passing in an anonymous function but rather an expression tree. This is done because inside DbAccessLayer we have to query ActiveRecord.Widget efficiently (LINQ to SQL) and not have the database return all ActiveRecord.Widget instances and then filter the enumerable collection. We need to pass in an expression tree, so we ask for one as the parameter for GetMany. The snag: the parameter we have needs to be magically transformed from an Expression<Func<DataContract.Widget, bool>> to an Expression<Func<ActiveRecord.Widget, bool>>. This is where I haven't managed to pull it off... Attempted Solution What we 'd like to do inside GetMany is: IEnumerable<DataContract.Widget> GetMany( Expression<Func<DataContract.Widget, bool>> predicate) { var lambda = Expression.Lambda<Func<ActiveRecord.Widget, bool>>( predicate.Body, predicate.Parameters); // use lambda to query ActiveRecord.Widget and return some value } This won't work because in a typical scenario, for example if: predicate == w => w.Id == 0; ...the expression tree contains a MemberAccessExpression instance which has a MemberInfo property (named Member) that point to members of DataContract.Widget. There are also ParameterExpression instances both in the expression tree and in its parameter expression collection (predicate.Parameters); After searching a bit, I found System.Linq.Expressions.ExpressionVisitor (its source can be found here in the context of a how-to, very helpful) which is a convenient way to modify an expression tree. Armed with this, I implemented a visitor. This simple visitor only takes care of changing the types in member access and parameter expressions. It may not be complete, but it's fine for the expression w => w.Id == 0. internal class Visitor : ExpressionVisitor { private readonly Func<Type, Type> dataContractToActiveRecordTypeConverter; public Visitor(Func<Type, Type> dataContractToActiveRecordTypeConverter) { this.dataContractToActiveRecordTypeConverter = dataContractToActiveRecordTypeConverter; } protected override Expression VisitMember(MemberExpression node) { var dataContractType = node.Member.ReflectedType; var activeRecordType = this.dataContractToActiveRecordTypeConverter(dataContractType); var converted = Expression.MakeMemberAccess( base.Visit(node.Expression), activeRecordType.GetProperty(node.Member.Name)); return converted; } protected override Expression VisitParameter(ParameterExpression node) { var dataContractType = node.Type; var activeRecordType = this.dataContractToActiveRecordTypeConverter(dataContractType); return Expression.Parameter(activeRecordType, node.Name); } } With this visitor, GetMany becomes: IEnumerable<DataContract.Widget> GetMany( Expression<Func<DataContract.Widget, bool>> predicate) { var visitor = new Visitor(...); var lambda = Expression.Lambda<Func<ActiveRecord.Widget, bool>>( visitor.Visit(predicate.Body), predicate.Parameters.Select(p => visitor.Visit(p)); var widgets = ActiveRecord.Widget.Repository().Where(lambda); // This is just for reference, see below Expression<Func<ActiveRecord.Widget, bool>> referenceLambda = w => w.Id == 0; // Here we 'd convert the widgets to instances of DataContract.Widget and // return them -- this has nothing to do with the question though. } Results The good news is that lambda is constructed just fine. The bad news is that it isn't working; it's blowing up on me when I try to use it (the exception messages are really not helpful at all). I have examined the lambda my code produces and a hardcoded lambda with the same expression; they look exactly the same. I spent hours in the debugger trying to find some difference, but I can't. When predicate is w => w.Id == 0, lambda looks exactly like referenceLambda. But the latter works with e.g. IQueryable<T>.Where, while the former does not (I have tried this in the immediate window of the debugger). I should also mention that when predicate is w => true, it all works just fine. Therefore I am assuming that I 'm not doing enough work in Visitor, but I can't find any more leads to follow on. Can someone point me in the right direction? Thanks in advance for your help!

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  • LINQ Expression<Func<T, bool>> equavalent of .Contains()

    - by BK
    Has anybody got an idea of how to create a .Contains(string) function using Linq Expressions, or even create a predicate to accomplish this public static Expression<Func<T, bool>> Or<T>(this Expression<Func<T, bool>> expr1, Expression<Func<T, bool>> expr2) { var invokedExpr = Expression.Invoke(expr2, expr1.Parameters.Cast<Expression>()); return Expression.Lambda<Func<T, bool>> (Expression.OrElse(expr1.Body, invokedExpr), expr1.Parameters); } Something simular to this would be ideal?

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  • Get the property, as a string, from an Expression<Func<TModel,TProperty>>

    - by Jaxidian
    I use some strongly-typed expressions that get serialized to allow my UI code to have strongly-typed sorting and searching expressions. These are of type Expression<Func<TModel,TProperty>> and are used as such: SortOption.Field = (p => p.FirstName);. I've gotten this working perfectly for this simple case. The code that I'm using for parsing the "FirstName" property out of there is actually reusing some existing functionality in a third-party product that we use and it works great, until we start working with deeply-nested properties(SortOption.Field = (p => p.Address.State.Abbreviation);). This code has some very different assumptions in the need to support deeply-nested properties. As for what this code does, I don't really understand it and rather than changing that code, I figured I should just write from scratch this functionality. However, I don't know of a good way to do this. I suspect we can do something better than doing a ToString() and performing string parsing. So what's a good way to do this to handle the trivial and deeply-nested cases? Requirements: Given the expression p => p.FirstName I need a string of "FirstName". Given the expression p => p.Address.State.Abbreviation I need a string of "Address.State.Abbreviation" While it's not important for an answer to my question, I suspect my serialization/deserialization code could be useful to somebody else who finds this question in the future, so it is below. Again, this code is not important to the question - I just thought it might help somebody. Note that DynamicExpression.ParseLambda comes from the Dynamic LINQ stuff and Property.PropertyToString() is what this question is about. /// <summary> /// This defines a framework to pass, across serialized tiers, sorting logic to be performed. /// </summary> /// <typeparam name="TModel">This is the object type that you are filtering.</typeparam> /// <typeparam name="TProperty">This is the property on the object that you are filtering.</typeparam> [Serializable] public class SortOption<TModel, TProperty> : ISerializable where TModel : class { /// <summary> /// Convenience constructor. /// </summary> /// <param name="property">The property to sort.</param> /// <param name="isAscending">Indicates if the sorting should be ascending or descending</param> /// <param name="priority">Indicates the sorting priority where 0 is a higher priority than 10.</param> public SortOption(Expression<Func<TModel, TProperty>> property, bool isAscending = true, int priority = 0) { Property = property; IsAscending = isAscending; Priority = priority; } /// <summary> /// Default Constructor. /// </summary> public SortOption() : this(null) { } /// <summary> /// This is the field on the object to filter. /// </summary> public Expression<Func<TModel, TProperty>> Property { get; set; } /// <summary> /// This indicates if the sorting should be ascending or descending. /// </summary> public bool IsAscending { get; set; } /// <summary> /// This indicates the sorting priority where 0 is a higher priority than 10. /// </summary> public int Priority { get; set; } #region Implementation of ISerializable /// <summary> /// This is the constructor called when deserializing a SortOption. /// </summary> protected SortOption(SerializationInfo info, StreamingContext context) { IsAscending = info.GetBoolean("IsAscending"); Priority = info.GetInt32("Priority"); // We just persisted this by the PropertyName. So let's rebuild the Lambda Expression from that. Property = DynamicExpression.ParseLambda<TModel, TProperty>(info.GetString("Property"), default(TModel), default(TProperty)); } /// <summary> /// Populates a <see cref="T:System.Runtime.Serialization.SerializationInfo"/> with the data needed to serialize the target object. /// </summary> /// <param name="info">The <see cref="T:System.Runtime.Serialization.SerializationInfo"/> to populate with data. </param> /// <param name="context">The destination (see <see cref="T:System.Runtime.Serialization.StreamingContext"/>) for this serialization. </param> public void GetObjectData(SerializationInfo info, StreamingContext context) { // Just stick the property name in there. We'll rebuild the expression based on that on the other end. info.AddValue("Property", Property.PropertyToString()); info.AddValue("IsAscending", IsAscending); info.AddValue("Priority", Priority); } #endregion }

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  • How To? Use an Expression Tree to call a Generic Method when the Type is only known at runtime.

    - by David Williams
    Please bear with me; I am very new to expression trees and lambda expressions, but trying to learn. This is something that I solved using reflection, but would like to see how to do it using expression trees. I have a generic function: private void DoSomeThing<T>( param object[] args ) { // Some work is done here. } that I need to call from else where in my class. Now, normally, this would be be simple: DoSomeThing<int>( blah ); but only if I know, at design time that I am working with an int. When I do not know the type until runtime is where I need the help. Like I said, I know how to do it via reflection, but I would like to do it via expression trees, as my (very limited) understanding is that I can do so. Any suggestions or points to sites where I can get this understanding, preferably with sample code?

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  • How do I use a Lambda expression to sort INTEGERS inside a object?

    - by punkouter
    I have a collection of objects and I know that I can sort by NAME (string type) by saying collEquipment.Sort((x, y) = string.Compare(x.ItemName, y.ItemName)); that WORKS. But I want to sort by a ID (integer type) and there is no such thing as Int32.Compare So how do I do this? This doesnt work collEquipment.Sort((x, y) = (x.ID < y.ID); //error I know the answer is going to be really simple. Lambda expressions confuse me.

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