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  • VB.net Dataset display different column

    - by Josh
    Hello, I am sure this has to a comon thing I just can't find it. I am making a combobox from my data source. Basically, This is a projects form and the user needs to select the the primary contact which is contrained by the customer id (GETbyCustomerID) set in another field. I have it working... mostly except the combobox only displays the contact ID which is completely useless to the user. I need to know how to display the First and Last name (both are seperate columns in the table). Any help? I am just using the designer.

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  • Does LINQ require significantly more processing cycles and memory than lower-level data iteration techniques?

    - by Matthew Patrick Cashatt
    Background I am recently in the process of enduring grueling tech interviews for positions that use the .NET stack, some of which include silly questions like this one, and some questions that are more valid. I recently came across an issue that may be valid but I want to check with the community here to be sure. When asked by an interviewer how I would count the frequency of words in a text document and rank the results, I answered that I would Use a stream object put the text file in memory as a string. Split the string into an array on spaces while ignoring punctuation. Use LINQ against the array to .GroupBy() and .Count(), then OrderBy() said count. I got this answer wrong for two reasons: Streaming an entire text file into memory could be disasterous. What if it was an entire encyclopedia? Instead I should stream one block at a time and begin building a hash table. LINQ is too expensive and requires too many processing cycles. I should have built a hash table instead and, for each iteration, only added a word to the hash table if it didn't otherwise exist and then increment it's count. The first reason seems, well, reasonable. But the second gives me more pause. I thought that one of the selling points of LINQ is that it simply abstracts away lower-level operations like hash tables but that, under the veil, it is still the same implementation. Question Aside from a few additional processing cycles to call any abstracted methods, does LINQ require significantly more processing cycles to accomplish a given data iteration task than a lower-level task (such as building a hash table) would?

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  • LINQ 4 XML - What is the proper way to query deep in the tree structure?

    - by Keith Barrows
    I have an XML structure that is 4 deep: <?xml version="1.0" encoding="utf-8"?> <EmailRuleList xmlns:xsd="EmailRules.xsd"> <TargetPST name="Tech Communities"> <Parse emailAsList="true" useJustDomain="false" fromAddress="false" toAddress="true"> <EmailRule address="@aspadvice.com" folder="Lists, ASP" saveAttachments="false" /> <EmailRule address="@sqladvice.com" folder="Lists, SQL" saveAttachments="false" /> <EmailRule address="@xmladvice.com" folder="Lists, XML" saveAttachments="false" /> </Parse> <Parse emailAsList="false" useJustDomain="false" fromAddress="false" toAddress="true"> <EmailRule address="[email protected]" folder="Special Interest Groups|Northern Colorado Architects Group" saveAttachments="false" /> <EmailRule address="[email protected]" folder="Support|SpamBayes" saveAttachments="false" /> </Parse> <Parse emailAsList="false" useJustDomain="false" fromAddress="true" toAddress="false"> <EmailRule address="[email protected]" folder="Support|GoDaddy" saveAttachments="false" /> <EmailRule address="[email protected]" folder="Support|No-IP.com" saveAttachments="false" /> <EmailRule address="[email protected]" folder="Discussions|Orchard Project" saveAttachments="false" /> </Parse> <Parse emailAsList="false" useJustDomain="true" fromAddress="true" toAddress="false"> <EmailRule address="@agilejournal.com" folder="Newsletters|Agile Journal" saveAttachments="false"/> <EmailRule address="@axosoft.ccsend.com" folder="Newsletters|Axosoft Newsletter" saveAttachments="false"/> <EmailRule address="@axosoft.com" folder="Newsletters|Axosoft Newsletter" saveAttachments="false"/> <EmailRule address="@cmcrossroads.com" folder="Newsletters|CM Crossroads" saveAttachments="false" /> <EmailRule address="@urbancode.com" folder="Newsletters|Urbancode" saveAttachments="false" /> <EmailRule address="@urbancode.ccsend.com" folder="Newsletters|Urbancode" saveAttachments="false" /> <EmailRule address="@Infragistics.com" folder="Newsletters|Infragistics" saveAttachments="false" /> <EmailRule address="@zdnet.online.com" folder="Newsletters|ZDNet Tech Update Today" saveAttachments="false" /> <EmailRule address="@sqlservercentral.com" folder="Newsletters|SQLServerCentral.com" saveAttachments="false" /> <EmailRule address="@simple-talk.com" folder="Newsletters|Simple-Talk Newsletter" saveAttachments="false" /> </Parse> </TargetPST> <TargetPST name="[Sharpen the Saw]"> <Parse emailAsList="false" useJustDomain="false" fromAddress="false" toAddress="true"> <EmailRule address="[email protected]" folder="Head Geek|Job Alerts" saveAttachments="false" /> <EmailRule address="[email protected]" folder="Social|LinkedIn USMC" saveAttachments="false"/> </Parse> <Parse emailAsList="false" useJustDomain="false" fromAddress="true" toAddress="false"> <EmailRule address="[email protected]" folder="Head Geek|Job Alerts" saveAttachments="false" /> <EmailRule address="[email protected]" folder="Head Geek|Job Alerts" saveAttachments="false" /> <EmailRule address="[email protected]" folder="Social|Cruise Critic" saveAttachments="false"/> </Parse> <Parse emailAsList="false" useJustDomain="true" fromAddress="true" toAddress="false"> <EmailRule address="@moody.edu" folder="Social|5 Love Languages" saveAttachments="false" /> <EmailRule address="@postmaster.twitter.com" folder="Social|Twitter" saveAttachments="false"/> <EmailRule address="@diabetes.org" folder="Physical|American Diabetes Association" saveAttachments="false"/> <EmailRule address="@membership.webshots.com" folder="Social|Webshots" saveAttachments="false"/> </Parse> </TargetPST> </EmailRuleList> Now, I have both an FromAddress and a ToAddress that is parsed from an incoming email. I would like to do a LINQ query against a class set that was deserialized from this XML. For instance: ToAddress = [email protected] FromAddress = [email protected] Query: Get EmailRule.Include(Parse).Include(TargetPST) where address == ToAddress AND Parse.ToAddress==true AND Parse.useJustDomain==false Get EmailRule.Include(Parse).Include(TargetPST) where address == [ToAddress Domain Only] AND Parse.ToAddress==true AND Parse.useJustDomain==true Get EmailRule.Include(Parse).Include(TargetPST) where address == FromAddress AND Parse.FromAddress==true AND Parse.useJustDomain==false Get EmailRule.Include(Parse).Include(TargetPST) where address == [FromAddress Domain Only] AND Parse.FromAddress==true AND Parse.useJustDomain==true I am having a hard time figuring this LINQ query out. I can, of course, loop on all the bits in the XML like so (includes deserialization into objects): XmlSerializer s = new XmlSerializer(typeof(EmailRuleList)); TextReader r = new StreamReader(path); _emailRuleList = (EmailRuleList)s.Deserialize(r); TargetPST[] PSTList = _emailRuleList.Items; foreach (TargetPST targetPST in PSTList) { olRoot = GetRootFolder(targetPST.name); if (olRoot != null) { Parse[] ParseList = targetPST.Items; foreach (Parse parseRules in ParseList) { EmailRule[] EmailRuleList = parseRules.Items; foreach (EmailRule targetFolders in EmailRuleList) { } } } } However, this means going through all these loops for each and every address. It makes more sense to me to query against the Objects. Any tips appreciated!

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  • linq query - The method or operation is not implemented.

    - by Dejan.S
    I'm doing the Rob Conery mvc storefront and at one place I'm suppose to get categories but I get an error with this linq query and I can not get why. It's exactly the same as his. var culturedName = from ct in ReadOnlyContext.CategoryCultureDetails where ct.Culture.LanguageCode == System.Globalization.CultureInfo.CurrentUICulture.TwoLetterISOLanguageName select new { ct.CategoryName, ct.CategoryId }; return from c in ReadOnlyContext.Categories join cn in culturedName on c.CategoryId equals cn.CategoryId select new Core.Model.Category { Id = c.CategoryId, Name = cn.CategoryName, ParentId = c.ParentId ?? 0, Products = new LazyList<Core.Model.Product>(from p in GetProducts() join cp in ReadOnlyContext.Categories_Products on p.Id equals cp.ProductId where cp.CategoryId == c.CategoryId select p) }; its the return query that mess things up. I have checked and the culturename actually gets data from the database. Appricate your help

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  • ASP.NET MVC <OutputCache> SqlDependency (CommandNotification?) with LINQ queries

    - by sinni800
    Hello, I use LINQ queries in my ASP.NET MVC application and want to use OutputCache in some of my Actions. I hear this should be possible with CommandNotifications. But those seem to only go for self-created SQLCommands, or am I wrong? Can I manually tell SQL server to send SQLDependency notifications if certain tables change? And if yes, how can I attach them to the OutputCache? Another side question: Can you do this with strongly types views too? Thank you in advance...

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  • How dynamic can I make my LINQ To SQL Statements?

    - by mcass20
    I have the need to construct a LINQ To SQL statement at runtime based on input from a user and I can't seem to figure out how to dynamically build the WHERE clause. I have no problem with the following: string Filters = "<value>FOO</value>"; Where("FormattedMessage.Contains(@0)",Filters) But what I really need is to make the entire WHERE clause dynamic. This way I can add multiple conditions at runtime like this (rough idea): foreach (Filter filter in filterlist) { whereclause = whereclause + "&& formattedmessage.contains(filter)"; }

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  • Using LINQ to XML, how can I join two sets of data based on ordinal position?

    - by Donald Hughes
    Using LINQ to XML, how can I join two sets of data based on ordinal position? <document> <set1> <value>A</value> <value>B</value> <value>C</value> </set1> <set2> <value>1</value> <value>2</value> <value>3</value> </set2> </document> Based on the above fragment, I would like to join the two sets together such that "A" and "1" are in the same record, "B" and "2" are in the same record, and "C" and "3" are in the same record.

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  • linq to xml. read. and assign to ViewData..noob

    - by raklos
    I have some xml similar to this: <?xml version="1.0" encoding="utf-8" ?> <data> <resources> <resource key="Title">Alpha</resource> <resource key="ImageName">Small.png</resource> <resource key="Desc">blah</resource> </resources> </data> using linq-xml how can i assign each resource here as a key value pair with the ViewData collection. Thanks.

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  • LINQ-to-XML to DataGridView: Cannot edit fields -- How to fix?

    - by Pretzel
    I am currently doing LINQ-to-XML and populating a DataGridView with my query just fine. The trouble I am running into is that once loaded into the DataGridView, the values appear to be Un-editable (ReadOnly). Here's my code: var barcodes = (from src in xmldoc.Descendants("Container") where src.Descendants().Count() > 0 select new { Id = (string)src.Element("Id"), Barcode = (string)src.Element("Barcode"), Quantity = float.Parse((string)src.Element("Quantity").Attribute("value")) }).Distinct(); dataGridView1.DataSource = barcodes.ToList(); I read somewhere that the "DataGridView will be in ReadOnly mode when you use Anonymous types." But I couldn't find an explanation why or exactly what to do about it. Any ideas?

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  • How to get List of results from list of ID values with LINQ to SQL?

    - by DaveDev
    I have a list of ID values: List<int> MyIDs { get; set; } I'd like to pass this list to an interface to my repository and have it return a List that match the ID values I pass in. List<MyType> myTypes = new List<MyType>(); IMyRepository myRepos = new SqlMyRepository(); myTypes = myRepos.GetMyTypes(this.MyIDs); Currently, GetMyTypes() behaves similarly to this: public MyType GetMyTypes(int id) { return (from myType in db.MyTypes where myType.Id == id select new MyType { MyValue = myType.MyValue }).FirstOrDefault(); } where I iterate through MyIDs and pass each id in and add each result to a list. How do I need to change the LINQ so that I can pass in the full list of MyIDs and get a list of MyTypes out? GetMyTypes() would have a signature similar to public List<MyType> GetMyTypes(List<int> myIds)

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  • Extending LINQ classes to my own partial classes in different namespaces?

    - by sah302
    I have a .dbml file which of course contains the auto-generated classes based on my tables. I would however, like to extend them to my own classes. Typically I design such that each of my tables get their own namespace in their own folder containing all of their associated dao and service classes. So if I am dealing with a page that only has to do with 'customers' for instance, I can only include the customerNS. But when using LINQ I seem to be unable to do this. I have tried removing a default namespace from the project, I have tried putting the .dbml file into it's own folder with a custom namespace and then adding a 'using' statement, but no nothing works. I also saw the Entity Namespace, Context Namespace, and Custom Tool Namespace properties associated with the .dbml file and tried setting all these to names x and trying 'using x' in my other class to allow me to extend partial classes, but it just doesn't work. Is this possible or do I have to keep all extended partial classes in the same namespace as the .dbml file?

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  • LINQ to SQL for tables across databases. Or View?

    - by BritishDeveloper
    I have a Message table and a User table. Both are in separate databases. There is a userID in the Message table that is used to join to the User table to find things like userName. How can I create this in LINQ to SQL? I can't seem to do a cross database join. Should I create a View in the database and use that instead? Will that work? What will happen to CRUD against it? E.g. if I delete a message - surely it won't delete the user? I'd imagine it would throw an error. What to do? I can't move the tables into the same database!

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  • Using Linq, how to separate a list in to grouped objects by name?

    - by Dr. Zim
    I have a table where a record looks like this varchar(255) Name varchar(255) Text varchar(255) Value Name is the DDL name, Text is what is displayed, and Value is returned upon selection. There are between one and twenty options for each Name. Without iterating though each option like a cursor, is there any way to pull out a list of objects, one for each unique DDL Name, using Linq and C#? A sample of the data: Beds '4 (10)' 4 Beds '5 (1)' 5 Beds '7 (1)' 7 Baths 'NA (13)' NULL Baths '0 (1)' 0 Baths '1 (13)' 1 I was thinking about doing an outer select to get the unique Names, then an inner select to get the list of options for it, then return the set as a List of a set of Lists.

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  • How can I use external expressions in Linq with EF4 (and LINQKit)?

    - by neo
    I want to separate out often used expressions in linq queries. I'm using Entity Framework 4 and also LINQKit but I still don't know how I should do it the right way. Let me give you an example: Article article = dataContainer.Articles.FirstOrDefault(a => a.Id == id); IEnumerable<Comment> comments = (from c in container.Comments where CommentExpressions.IsApproved.Invoke(c) select c); public static class CommentExpressions { public static Expression<Func<Module, bool>> IsApproved { get { return m => m.IsApproved; } } } Of course the IsApproved expression would be something much more complicated. The problem is that the Invoke() won't work because I didn't call .asExpandable() from LINQKit on container.Comments but I can't call it because it's just an ICollection instead of an ObjectSet. So my question is: Do I always have to go through the data context when I want to include external expressions or can I somehow use it on the object I fetched (Article)? Any ideas or best practices? Thanks very much! neo

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  • How to get rank from full-text search query with Linq to SQL?

    - by Stephen Jennings
    I am using Linq to SQL to call a stored procedure which runs a full-text search and returns the rank plus a few specific columns from the table Article. The rank column is the rank returned from the SQL function FREETEXTTABLE(). I've added this sproc to the data model designer with return type Article. This is working to get the columns I need; however, it discards the ranking of each search result. I'd like to get this information so I can display it to the user. So far, I've tried creating a new class RankedArticle which inherits from Article and adds the column Rank, then changing the return type of my sproc mapping to RankedArticle. When I try this, an InvalidOperationException gets thrown: Data member 'Int32 ArticleID' of type 'Heap.Models.Article' is not part of the mapping for type 'RankedArticle'. Is the member above the root of an inheritance hierarchy? I can't seem to find any other questions or Google results from people trying to get the rank column, so I'm probably missing something obvious here.

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  • ASP.NET MVC 2: How to write this Linq SQL as a Dynamic Query (using strings)?

    - by Dr. Zim
    Skip to the "specific question" as needed. Some background: The scenario: I have a set of products with a "drill down" filter (Query Object) populated with DDLs. Each progressive DDL selection will further limit the product list as well as what options are left for the DDLs. For example, selecting a hammer out of tools limits the Product Sizes to only show hammer sizes. Current setup: I created a query object, sent it to a repository, and fed each option to a SQL "table valued function" where null values represent "get all products". I consider this a good effort, but far from DDD acceptable. I want to avoid any "programming" in SQL, hopefully doing everything with a repository. Comments on this topic would be appreciated. Specific question: How would I rewrite this query as a Dynamic Query? A link to something like 101 Linq Examples would be fantastic, but with a Dynamic Query scope. I really want to pass to this method the field in quotes "" for which I want a list of options and how many products have that option. (from p in db.Products group p by p.ProductSize into g select new Category { PropertyType = g.Key, Count = g.Count() }).Distinct(); Each DDL option will have "The selection (21)" where the (21) is the quantity of products that have that attribute. Upon selecting an option, all other remaining DDLs will update with the remaining options and counts.

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  • Can I use the auto-generated Linq-to-SQL entity classes in 'disconnected' mode?

    - by Gary McGill
    Suppose I have an automatically-generated Employee class based on the Employees table in my database. Now suppose that I want to pass employee data to a ShowAges method that will print out name & age for a list of employees. I'll retrieve the data for a given set of employees via a linq query, which will return me a set of Employee instances. I can then pass the Employee instances to the ShowAges method, which can access the Name & Age fields to get the data it needs. However, because my Employees table has relationships with various other tables in my database, my Employee class also has a Department field, a Manager field, etc. that provide access to related records in those other tables. If the ShowAges method were to invoke any of those methods, this would cause lots more data to be fetched from the database, on-demand. I want to be sure that the ShowAges method only uses the data I have already fetched for it, but I really don't want to have to go to the trouble of defining a new class which replicates the Employee class but has fewer methods. (In my real-world scenario, the class would have to be considerably more complex than the Employee class described here; it would have several 'joined' classes that do need to be populated, and others that don't). Is there a way to 'switch off' or 'disconnect' the Employees instances so that an attempt to access any property or related object that's not already populated will raise an exception? If not, then I assume that since this must be a common requirement, there might be an already-established pattern for doing this sort of thing?

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  • Can LINQ expression classes implement the observer pattern instead of deferred execution?

    - by Tormod
    Hi. We have issues within an application using a state machine. The application is implemented as a windows service and is iteration based (it "foreaches" itself through everything) and there are myriads of instances being processed by the state machine. As I'm reading the MEAP version of Jon Skeets book "C# in Depth, 2nd ed", I'm wondering if I can change the whole thing to use linq expression instances so that guards and conditions are represented using expression trees. We are building many applications on this state machine engine and would probably greatly benefit from the new Expression tree visualizer in VS 2010 Now, simple example. If I have an expression tree where there is an OR Expression condition with two sub nodes, is there any way that these can implement the observer pattern so that the expression tree becomes event driven? If a condition change, it should notify its parent node (the OR node). Since the OR node then changes from "false" to "true", then it should notify ITS parent and so on. I love the declarative model of expression trees, but the deferred execution model works in opposite direction of the control flow if you want event based "live" conditions. Am I off on a wild goose chase here? Or is there some concept in the BCL that may help me achieve this?

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  • LINQ to SQL - How to efficiently do either an AND or an OR search for multiple criteria

    - by Dan Diplo
    I have an ASP.NET MVC site (which uses Linq To Sql for the ORM) and a situation where a client wants a search facility against a bespoke database whereby they can choose to either do an 'AND' search (all criteria match) or an 'OR' search (any criteria match). The query is quite complex and long and I want to know if there is a simple way I can make it do both without having to have create and maintain two different versions of the query. For instance, the current 'AND' search looks something like this (but this is a much simplified version): private IQueryable<SampleListDto> GetSampleSearchQuery(SamplesCriteria criteria) { var results = from r in Table where (r.Id == criteria.SampleId) && (r.Status.SampleStatusId == criteria.SampleStatusId) && (r.Job.JobNumber.StartsWith(criteria.JobNumber)) && (r.Description.Contains(criteria.Description)) select r; } I could copy this and replace the && with || operators to get the 'OR' version, but feel there must be a better way of achieving this. Does anybody have any suggestions how this can be achieved in an efficient and flexible way that is easy to maintain? Thanks.

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  • [C#]How to introduce retry logic into LINQ to SQL to deal with timeouts?

    - by codemonkie
    I need to find ways to add retry mechanism to my DB calls in case of timeouts, LINQ to SQL is used to call some sprocs in my code... using (MyDataContext dc = new MyDataContext()) { int result = -1; //denote failure int count = 0; while ((result < 0) && (count < MAX_RETRIES)) { result = dc.myStoredProc1(...); count++; } result = -1; count = 0; while ((result < 0) && (count < MAX_RETRIES)) { result = dc.myStoredProc2(...); count++; } ... ... } Not sure if the code above is right or posed any complications. It'll be nice to throw an exception after MAX_RETRIES has reached, but I dunno how and where to throw them appropriately :-) Any helps appreciated.

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  • Important question about linq to SQL performance on high loaded web applications

    - by Alex
    I started working with linq to SQL several weeks ago. I got really tired of working with SQL server directly through the SQL queries (sqldatareader, sqlcommand and all this good stuff).  After hearing about linq to SQL and mvc I quickly moved all my projects to these technologies. I expected linq to SQL work slower but it suprisongly turned out to be pretty fast, primarily because I always forgot to close my connections when using datareaders. Now I don't have to worry about it. But there's one problem that really bothers me. There's one page that's requested thousands of times a day. The system gets data in the beginning, works with it and updates it. Primarily the updates are ++ @ -- (increase and decrease values). I used to do it like this UPDATE table SET value=value+1 WHERE ID=@I'd It worked with no problems obviously. But with linq to SQL the data is taken in the beginning, moved to the class, changed and then saved. Stats.registeredusers++; Db.submitchanges(); Let's say there were 100 000 users. Linq will say "let it be 100 001" instead of "let it be increased by 1". But if there value of users has already been increased (that happens in my site all the time) then linq will be like oops, this value is already 100 001. Whatever I'll throw an exception" You can change this behavior so that it won't throw an exception but it still will not set the value to 100 002. Like I said, it happened with me all the time. The stas value was increased twice a second on average. I simply had to rewrite this chunk of code with classic ado net. So my question is how can you solve the problem with linq

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  • LINQ Query using UDF that receives parameters from the query

    - by Ben Fidge
    I need help using a UDF in a LINQ which calculates a users position from a fixed point. int pointX = 567, int pointY = 534; // random points on a square grid var q = from n in _context.Users join m in _context.GetUserDistance(n.posY, n.posY, pointX, pointY, n.UserId) on n.UserId equals m.UserId select new User() { PosX = n.PosX, PosY = n.PosY, Distance = m.Distance, Name = n.Name, UserId = n.UserId }; The GetUserDistance is just a UDF that returns a single row in a TVP with that users distance from the points deisgnated in pointX and pointY variables, and the designer generates the following for it: [global::System.Data.Linq.Mapping.FunctionAttribute(Name="dbo.GetUserDistance", IsComposable=true)] public IQueryable<GetUserDistanceResult> GetUserDistance([global::System.Data.Linq.Mapping.ParameterAttribute(Name="X1", DbType="Int")] System.Nullable<int> x1, [global::System.Data.Linq.Mapping.ParameterAttribute(Name="X2", DbType="Int")] System.Nullable<int> x2, [global::System.Data.Linq.Mapping.ParameterAttribute(Name="Y1", DbType="Int")] System.Nullable<int> y1, [global::System.Data.Linq.Mapping.ParameterAttribute(Name="Y2", DbType="Int")] System.Nullable<int> y2, [global::System.Data.Linq.Mapping.ParameterAttribute(Name="UserId", DbType="Int")] System.Nullable<int> userId) { return this.CreateMethodCallQuery<GetUserDistanceResult>(this, ((MethodInfo)(MethodInfo.GetCurrentMethod())), x1, x2, y1, y2, userId); } when i try to compile i get The name 'n' does not exist in the current context

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  • linq: SQL performance on high loaded web applications

    - by Alex
    I started working with linq to SQL several weeks ago. I got really tired of working with SQL server directly through the SQL queries (sqldatareader, sqlcommand and all this good stuff).  After hearing about linq to SQL and mvc I quickly moved all my projects to these technologies. I expected linq to SQL work slower but it suprisongly turned out to be pretty fast, primarily because I always forgot to close my connections when using datareaders. Now I don't have to worry about it. But there's one problem that really bothers me. There's one page that's requested thousands of times a day. The system gets data in the beginning, works with it and updates it. Primarily the updates are ++ @ -- (increase and decrease values). I used to do it like this UPDATE table SET value=value+1 WHERE ID=@I'd It worked with no problems obviously. But with linq to SQL the data is taken in the beginning, moved to the class, changed and then saved. Stats.registeredusers++; Db.submitchanges(); Let's say there were 100 000 users. Linq will say "let it be 100 001" instead of "let it be increased by 1". But if there value of users has already been increased (that happens in my site all the time) then linq will be like oops, this value is already 100 001. Whatever I'll throw an exception" You can change this behavior so that it won't throw an exception but it still will not set the value to 100 002. Like I said, it happened with me all the time. The stas value was increased twice a second on average. I simply had to rewrite this chunk of code with classic ado net. So my question is how can you solve the problem with linq

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  • How to write this Linq SQL as a Dynamic Query (using strings)?

    - by Dr. Zim
    Skip to the "specific question" as needed. Some background: The scenario: I have a set of products with a "drill down" filter (Query Object) populated with DDLs. Each progressive DDL selection will further limit the product list as well as what options are left for the DDLs. For example, selecting a hammer out of tools limits the Product Sizes to only show hammer sizes. Current setup: I created a query object, sent it to a repository, and fed each option to a SQL "table valued function" where null values represent "get all products". I consider this a good effort, but far from DDD acceptable. I want to avoid any "programming" in SQL, hopefully doing everything with a repository. Comments on this topic would be appreciated. Specific question: How would I rewrite this query as a Dynamic Query? A link to something like 101 Linq Examples would be fantastic, but with a Dynamic Query scope. I really want to pass to this method the field in quotes "" for which I want a list of options and how many products have that option. from p in db.Products group p by p.ProductSize into g select new Category { PropertyType = g.Key, Count = g.Count() } Each DDL option will have "The selection (21)" where the (21) is the quantity of products that have that attribute. Upon selecting an option, all other remaining DDLs will update with the remaining options and counts. Edit: Additional notes: .OrderBy("it.City") // "it" refers to the entire record .GroupBy("City", "new(City)") // This produces a unique list of City .Select("it.Count()") //This gives a list of counts... getting closer .Select("key") // Selects a list of unique City .Select("new (key, count() as string)") // +1 to me LOL. key is a row of group .GroupBy("new (City, Manufacturer)", "City") // New = list of fields to group by .GroupBy("City", "new (Manufacturer, Size)") // Second parameter is a projection Product .Where("ProductType == @0", "Maps") .GroupBy("new(City)", "new ( null as string)")// Projection not available later? .Select("new (key.City, it.count() as string)")// GroupBy new makes key an object Product .Where("ProductType == @0", "Maps") .GroupBy("new(City)", "new ( null as string)")// Projection not available later? .Select("new (key.City, it as object)")// the it object is the result of GroupBy var a = Product .Where("ProductType == @0", "Maps") .GroupBy("@0", "it", "City") // This fails to group Product at all .Select("new ( Key, it as Product )"); // "it" is property cast though What I have learned so far is LinqPad is fantastic, but still looking for an answer. Eventually, completely random research like this will prevail I guess. LOL. Edit:

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