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  • How do I connect remotely to SQL Server from Windows client?

    - by humble_coder
    Hi All, Having a bit of an issue connecting to SQL SERVER remotely from Windows. I've verified that all of my settings are correct via SQL SERVER MANAGEMENT STUDIO EXPRESS and SQL SERVER CONFIGURATION MANAGER. I can connect remotely using ODBC drivers from other OSes (e.g. OS X, Linux, etc). However, when I connect with the same credentials from a remote Windows machine using "SQL SERVER" as the driver I am told that the system cannot connect. I've tried creating an ODBC Data Source and I get the same error: Connection failed: SQLState: '01000' SQL Server Error: 14 [Microsoft][ODBC SQL Server Driver][TCP/IP Sockets]ConnectionOpen(InvalidInstance()). Connection failed: SQLState: '08001' SQL Server Error: 14 [Microsoft][ODBC SQL Server Driver][TCP/IP Sockets]Invalid Connection From the non-windows machines I can use the IP address of the SQL Server just fine. However, on the remote Windows machine, neither IP address nor named instance works. FYI, I can create an ODBC Data Source using the named instance on the machine actually running the SQL Server (but this is, of course, nothing special -- just proof that it isn't completely hosed). One interesting note: If I use SQL STUDIO 2005 from a Windows client machine, I can use the IP address to connect remotely. Still, the whole reason I bring this up is because I need to use a software package I've written to connect to SQL Server remotely from Windows machines as well. Previously the solution was only needed to xfer data from SQL Server into a PostGRES or MySQL database on non-Windows machines (due to DBA preference). However, now they also want to move the data from the legacy software to MySQL even on Windows. Any assistance would be most appreciated. Feel free to provide a full example connection string. Best

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  • LINQDataSource - Query Multiple Tables?

    - by davemackey
    I have a database and I've created a DBML Linq-to-SQL file to represent this database. I've created a new aspx page and dropped a linqdatasource and a formview control onto it. When I configure the linqdatasource it gives me the choice only to select * from one table...but I want to pull from multiple tables. e.g. I have tables like simple_person, simple_address, simple_phone, and I want to pull from all of them. How can I accomplish this?

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  • Group by and order by

    - by Simon Thompson
    using LINQ to NHibernate does anybody know how to use group by and order by in the same expression. I am having to execute the group by into a list and then order this, seem that I am missing soemthing here ??? Example:- Private function LoadStats(...) ... Dim StatRepos As DataAccess.StatsExtraction_vwRepository = New DataAccess.StatsExtraction_vwRepository return (From x In StatRepos.GetAnswers(Question, Questionnaire) _ Group x By xData = x.Data Into Count() _ Select New ChartData With {.TheData = xData, .TheValue = xData.Count} ).ToList.OrderBy(Function(x) x.TheData) End Sub

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  • Select some records ...

    - by Kris-I
    I have an IList<MyList>. I'd like with LINQ keep the same list (same number of record) but I'd like reduce or/and rename some record. At the end I'd like to have IList<MyNewList>.

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  • Friendly way to parse XDocument

    - by Oli
    I have a class that various different XML schemes are created from. I create the various dynamic XDocuments via one (Very long) statement using conditional operators for optional elements and attributes. I now need to convert the XDocuments back to the class but as they are coming from different schemes many elements and sub elements may be optional. The only way I know of doing this is to use a lot of if statements. This approach doesn't seem very LINQ and uses a great deal more code than when I create the XDocument so I wondered if there is a better way to do this? An example would be to get <?xml version="1.0"?> <root xmlns="somenamespace"> <object attribute1="This is Optional" attribute2="This is required"> <element1>Required</element1> <element1>Optional</element1> <List1> Optional List Of Elements </List1> <List2> Required List Of Elements </List2> </object> </root> Into public class Object() { public string Attribute1; public string Attribute2; public string Element1; public string Element2; public List<ListItem1> List1; public List<ListItem2> List2; } In a more LINQ friendly way than this: public bool ParseXDocument(string xml) { XNamespace xn = "somenamespace"; XDocument document = XDocument.Parse(xml); XElement elementRoot = description.Element(xn + "root"); if (elementRoot != null) { //Get Object Element XElement elementObject = elementRoot.Element(xn + "object"); if(elementObject != null) { if(elementObject.Attribute(xn + "attribute1") != null) { Attribute1 = elementObject.Attribute(xn + "attribute1"); } if(elementObject.Attribute(xn + "attribute2") != null) { Attribute2 = elementObject.Attribute(xn + "attribute2"); } else { //This is a required Attribute so return false return false; } //If, If/Elses get deeper and deeper for the next elements and lists etc.... } else { //Object is a required element so return false return false; } } else { //Root is a required element so return false return false; } return true; } Update: Just to clarify the ParseXDocument method is inside the "Object" class. Every time an xml document is received the Object class instance has some or all of it's values updated.

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  • Olympics data available for all on Windows Azure SQL Database and Power View

    - by jamiet
    Are you looking around for some decent test data for your BI demos? Well, if so, Microsoft have provided some data about all medals won at the Olympics Games (1900 to 2008) at OlympicsData workbook - Excel, SSIS, Azure sample; it provides analysis over athletes, countries, medal type, sport, discipline and various other dimensions. The data has been provided in an Excel workbook along with instructions on how to load the data into a Windows Azure SQL Database using SQL Server Integration Services (SSIS). Frankly though, the rigmarole of standing up your own Windows Azure SQL Database ok, SQL Azure database, is both costly (SQL Azure isn’t free) and time consuming (the provided instructions aren’t exactly an idiot’s guide and getting SSIS to work properly with Excel isn’t a barrel of laughs either). To ease the pain for all you BI folks out there that simply want to party on the data I have loaded it all into the SQL Azure database that I use for hosting AdventureWorks on Azure. You can read more about AdventureWorks on Azure below however I’ll summarise here by saying it is a SQL Azure database provided for the use of the SQL Server community and which is supported by voluntary donations. To view the data the credentials you need are: Server mhknbn2kdz.database.windows.net  Database AdventureWorks2012 User sqlfamily Password sqlf@m1ly Type those into SSMS and away you go, the data is provided in four tables [olympics].[Sport], [olympics].[Discipline], [olympics].[Event] & [olympics].[Medalist]: I figured this would be a good candidate for a Power View report so I fired up Excel 2013 and built such a report to slice’n’dice through the data – here are some screenshots that should give you a flavour of what is available: A view of all the available data Where do all the gymastics medals go? Which countries do top ten all-time medal winners come from? You get the idea. There is masses of information here and if you have Excel 2013 handy Power View provides a quick and easy way of surfing through it. To save you the bother of setting up the Power View report yourself you can have the one that I took these screenshots from, it is available on my SkyDrive at OlympicsAnalysis.xlsx so just hit the link and download to play to your heart’s content. Party on, people! As I said above the data is hosted on a SQL Azure database that I use for hosting “AdventureWorks on Azure” which I first announced in March 2013 at AdventureWorks2012 now available for all on SQL Azure. I’ll repeat the pertinent parts of that blog post here: I am pleased to announce that as of today … [AdventureWorks2012] now resides on SQL Azure and is available for anyone, absolutely anyone, to connect to and use for their own means. This database is free for you to use but SQL Azure is of course not free so before I give you the credentials please lend me your ears eyes for a short while longer. AdventureWorks on Azure is being provided for the SQL Server community to use and so I am hoping that that same community will rally around to support this effort by making a voluntary donation to support the upkeep which, going on current pricing, is going to be $119.88 per year. If you would like to contribute to keep AdventureWorks on Azure up and running for that full year please donate via PayPal to [email protected] Any amount, no matter how small, will help. If those 50+ people that retweeted me beforehand all contributed $2 then that would just about be enough to keep this up for a year. If the community contributes more than we need then there are a number of additional things that could be done: Host additional databases (Northwind anyone??) Host in more datacentres (this first one is in Western Europe) Make a charitable donation That last one, a charitable donation, is something I would really like to do. The SQL Community have proved before that they can make a significant contribution to charitable orgnisations through purchasing the SQL Server MVP Deep Dives book and I harbour hopes that AdventureWorks on Azure can continue in that vein. So please, if you think AdventureWorks on Azure is something that is worth supporting please make a contribution. I’d like to emphasize that last point. If my hosting this Olympics data is useful to you please support this initiative by donating. Thanks in advance. @Jamiet

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  • Manual (Dynamic) LINQ subquery using IN clause

    - by immortalali-msn-com
    Hi Everyone, I want to query the DB through LINQ writing manual SQL, my linq method is: var q = db.TableView.Where(sqlAfterWhere); returnValue = q.Count(); this method queries well if the value passed to variable "sqlAfterWhere" is: (this variable is String type) it.Name = 'xyz' but what if i want to use IN clause, using a sub query. (i need to use 'it' before every column name in the above query to work), i cant use 'it' before the sub query columns as its a separate query, so what should i do, if i dont use any thing, and use column names directly it gives error saying " could not be resolved" where is my column names with out 'it' at the begining. So the query not working is: (this is a string passed to the variable above): it.Name IN (SELECT Name FROM TableName WHERE Address LIKE '%SomeAddress%') the errors come out as: Name could not be resolved Address could not be resolved The exact error is: "'Name' could not be resolved in the current scope or context. Make sure that all referenced variables are in scope, that required schemas are loaded, and that namespaces are referenced correctly., near simple identifier, line 6, column 25." Same error for "Address as well if i use 'it.' before these columns it gives error as: "The element type 'Edm.Int32' and the CollectionType 'Transient.collection[Transient.rowtype(GroupID,Edm.Int32(Nullable=True,DefaultValue=))]' are not compatible. The IN expression only supports entity, primitive, and reference types. , near WHERE predicate, line 6, column 14." Thanks for the help

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  • LINQ - IEnumerable.Join on Anonymous Result Set in VB.NET

    - by user337501
    I've long since built a way around this, but it still keeps bugging me... it doesnt help that my grasp of dynamic LINQ queries is still shakey. For the example: Parent has fields (ParentKey, ParentField) Child has fields (ChildKey, ParentKey, ChildField) Pet has fields (PetKey, ChildKey, PetField) Child has a foreign key reference to Parent on Child.ParentKey = Parent.ParentKey Pet has a foreign key reference to Child on Pet.Childkey = Child.ChildKey Simple enough eh? Lets say I have LINQ like this... Dim Q = FROM p in DataContext.Parent _ Join c In DataContext.Child On c.ParentKey = p.ParentKey Consider this a "base query" on which I will perform other filtering actions. Now I want to join the Pet table like this: Q = Q.Join(DataContext.Pet, _ Function(a) a.c.ChildKey, _ Function(p As Pet) p.ChildKey, _ Function(a, p As Pet) p.ChildKey = a.c.ChildKey) The above Join call doesnt work. I sort of understand why it doesnt work, but hopefully it'll show you how I tried to accomplish this task. After all this was done I would have appended a Select to finish the job. Any ideas on a better way to do this? I tried it with the PredicateBuilder with little success. I might not know how to use it right but it felt like it wasnt gonna handle the joining.

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  • Linq-to-Sql IIS7 Login failed for user ‘DOMAIN\MACHINENAME$’

    - by cfdev9
    I am encountering unexpected behaviour using Linq-to-sql DataContext. When I run my application locally it works as expected however after deploying to a test server which runs IIS7, I get an error Login failed for user ‘DOMAIN\MACHINENAME$’ when attempting to open objects from the DataContext. This code explains the error, which breaks on the very last line with the error "System.Data.SqlClient.SqlException: Login failed for user". var connStr ="Data Source=server;Initial Catalog=Test;User Id=testuser;Password=password"; //Test 1 var conn1 = new System.Data.SqlClient.SqlConnection(connStr); var cmdString = "SELECT COUNT(*) FROM Table1"; var cmd = new System.Data.SqlClient.SqlCommand(cmdString, conn1); conn1.Open(); var count1 = cmd.ExecuteScalar(); conn1.Close(); //Test 2 var conn2 = new System.Data.SqlClient.SqlConnection(connStr); var context = new TestDataContext(conn2); var count2 = context.Table1s.Count(); The connection string is not even using integrated security, so why is Linq-to-sql trying to connect as a specific user? If I change the server name in the connection string I get a different error so its using atleast part of the connection string, but apparently ignoring the UserId and Password. Very confused.

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  • Linq-To-Objects group by

    - by Oskar Kjellin
    Hey, I'm building a software for timereporting I have a Dictionary<string, Dictionary<string, double>>. The key in the main dictionary is a users name and their value is a dictionary of . I have a function GetDepartment(string UserName) which returns a string with the users department. What I want is to crate a new dictionary, of the same type, that has the department as the main key and in the subdictionary a where hours is the total for that department. I have been trying to do this with linq but did not succeed. Would be very glad for some help here! EDIT: This code does exactly what I want. But I want it in LINQ Dictionary<string, Dictionary<string, double>> temphours = new Dictionary<string, Dictionary<string, double>>(); ; foreach (var user in hours) { string department = GetDepartment(user.Key); if (!temphours.ContainsKey(department)) { temphours.Add(department, new Dictionary<string, double>()); } foreach (var customerReport in user.Value) { if (!temphours[department].ContainsKey(customerReport.Key)) { temphours[department].Add(customerReport.Key, 0); } temphours[department][customerReport.Key] += customerReport.Value; } }

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  • C# Linq List Contains Similar Elements

    - by John Peters
    Hi All, I am looking for linq query to see if there exists a similar object I have an object graph as follows Cart myCart = new Cart { List<CartProduct> myCartProduct = new List<CartProduct> { CartProduct cartProduct1 = new CartProduct { List<CartProductAttribute> a = new List<CartProductAttribute> { CartProductAttribute cpa1 = new CartProductAttribute{ title="red" }, CartProductAttribute cpa2 = new CartProductAttribute{ title="small" } } } CartProduct cartProduct2 = new CartProduct { List<CartProductAttribute> d = new List<CartProductAttribute> { CartProductAttribute cpa3 = new CartProductAttribute{ title="john" }, CartProductAttribute cpa4 = new CartProductAttribute{ title="mary" } } } } } I would like to get from the Cart = a CartProduct that has the exact same CartProductAttribute title values as a CartProduct that I need to compare. No more and no less. E.G. I need to find a similar CartProduct that has a CartProductAttribute with title="red" and a cartProductAttribute with title="small" in myCart (eg 'cartProduct1' in the example) CartProduct cartProductToCompare = new CartProduct { List<CartProductAttribute> cartProductToCompareAttributes = new List<CartProductAttribute> { CartProductAttribute cpa5 = new CartProductAttribute{ title="red" }, CartProductAttribute cpa6 = new CartProductAttribute{ title="small" } } } So from object graph myCart cartProduct1 cpa1 (title=red) cpa2 (title=small) cartProduct2 cpa3 (title=john) cpa4 (title=mary) Linq query looking for cartProductToCompare cpa5 (title=red) cpa6 (title=small) Should find cartProduct1 Hope all this makes sense... Thanks

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  • Cannot update a single field using Linq to Sql

    - by KallDrexx
    I am having a hard time attempting to update a single field without having to retrieve the whole record prior to saving. For example, in my web application I have an in place editor for the Name and Description fields of an object. Once you edit either field, it sends the new field (with the object's ID value) to the web server. What I want is the webserver to take that value and ID and only update the one field. There are only two ways google tells me to do this: 1) When I get the value I want to change, the value and the ID, retrieve the record from the database, update the field in the c# object, and then send it back to the server. I don't like this method because not only does it include a completely unnecessary database read call (which includes two tables due to the way my schema is). 2) Set UpdateCheck for all the fields (but the primary keys) to UpdateCheck.Never. This doesn't work for me (I think) due to my mapping layer between the Linq to Sql and my Entity/ViewModel layer. When I convert my entity into the linq to sql db object it seems to be updating those fields regardless of the UpdateCheck setting. This might be just because of integers, since not setting an int means it is a zero (and no, I can't use int? instead). Are there any other options that I have?

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  • SelectMany in Linq to entity

    - by Brazeta
    I was looking at some examples in microsoft site about linq and I see an example that I need to modify! http://msdn.microsoft.com/en-us/vcsharp/aa336758.aspx#SelectManyCompoundfrom3 public void Linq16() { List customers = GetCustomerList(); var orders = from c in customers from o in c.Orders where o.OrderDate >= new DateTime(1998, 1, 1) select new { c.CustomerID, o.OrderID, o.OrderDate }; ObjectDumper.Write(orders); } Insted of having a select that retrives the CustomerID, OrderID and OrderDate I want to select the CustomerID and a System.Collection.Generic.List that contains all the orders for that user! Essentially I want to group my orders by CustomerID, but i noticed that linq to entity does not allow a .ToList(object) inside the select. I want something like this... List customers = GetCustomerList(); var orders = from c in customers from o in c.Orders where o.OrderDate >= new DateTime(1998, 1, 1) select new xpto { TheCostumerID = c.CustomerID, CostumerOrders = o.Select(i=>i.OrderID).ToList(), }; ...but the .ToList() is a big problem, at least for me. I'm trying to find out the solution for that but so far I have acomplished nothing! Please help me.

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  • populating object collection property with Linq

    - by Benjamin Ortuzar
    I have an XML structure that has many doc nodes, and each node may have zero or more extract paragraphs (paras). <doc> <docitem>3</docitem> <docid>129826</docid> <doctitle>sample title</doctitle> <docdatetime>2009-07-03T16:59:00</docdatetime> <collectdatetime>2009-07-03T16:59:23</collectdatetime> <summary> <summarytext>sample summary</summarytext> </summary> <paras> <paraitemcount>2</paraitemcount> <para> <paraitem>1</paraitem> <paratext>sample text 1</paratext> </para> <para> <paraitem>2</paraitem> <paratext>sample text 2</paratext> </para> </paras> </doc> <doc> ... </doc> I also has some Linq code to populate some Document objects: List<Document> documentsList = (from doc in xmlDocument.Descendants("doc") select new Document { DocId = doc.Element("docid").Value, DocTitle = doc.Element("doctitle").Value, DocDateTime = DateTime.Parse(doc.Element("docdate").Value), DocSummary = doc.Element("summary").Value, DocParas = "" ///missing code to populate List<string> } ).ToList<Document>(); Is it possible add all the paras nodes into the Document.DocParas List<string> using Linq and Xpath, or should I do this task in a different way? Note: I'm using .NET C# 3.5

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  • Create System.Data.Linq.Table in Code for Testing

    - by S. DePouw
    I have an adapter class for Linq-to-Sql: public interface IAdapter : IDisposable { Table<Data.User> Activities { get; } } Data.User is an object defined by Linq-to-Sql pointing to the User table in persistence. The implementation for this is as follows: public class Adapter : IAdapter { private readonly SecretDataContext _context = new SecretDataContext(); public void Dispose() { _context.Dispose(); } public Table<Data.User> Users { get { return _context.Users; } } } This makes mocking the persistence layer easy in unit testing, as I can just return whatever collection of data I want for Users (Rhino.Mocks): Expect.Call(_adapter.Users).Return(users); The problem is that I cannot create the object 'users' since the constructors are not accessible and the class Table is sealed. One option I tried is to just make IAdapter return IEnumerable or IQueryable, but the problem there is that I then do not have access to the methods ITable provides (e.g. InsertOnSubmit()). Is there a way I can create the fake Table in the unit test scenario so that I may be a happy TDD developer?

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  • Beginner LINQ to XML inline XML error

    - by Kyle B.
    Imports System.Xml.Linq Imports System.Linq Partial Class test2 Inherits System.Web.UI.Page Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim xml As XElement = <book> <title>My Title</title> <author>Kyle</author> <publisher>WROX</publisher> </book> End Sub End Class The above code is producing the following error: Compiler Error Message: BC30201: Expression expected. Source Error: Line 8: Line 9: Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Line 10: Dim xml As XElement = <book> Line 11: <title>My Title</title> Line 12: <author>Kyle</author> Source File: C:\Inetpub\wwwroot\myproject\web\test2.aspx.vb Line: 10 Why? edit: Dim xml As XElement = New XElement("book", _ New XElement("title", "My Title"), _ New XElement("author", "Kyle"), _ New XElement("publisher", "WROX") _ ) The above code works, but obviously is not as elegant as the original and I would still appreciate an explanation of why my original syntax is wrong.

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  • Linq-To-Entities group by

    - by Oskar Kjellin
    Hey, I'm building a software for timereporting I have a Dictionary<string, Dictionary<string, double>>. The key in the main dictionary is a users name and their value is a dictionary of . I have a function GetDepartment(string UserName) which returns a string with the users department. What I want is to crate a new dictionary, of the same type, that has the department as the main key and in the subdictionary a where hours is the total for that department. I have been trying to do this with linq but did not succeed. Would be very glad for some help here! EDIT: This code does exactly what I want. But I want it in LINQ Dictionary<string, Dictionary<string, double>> temphours = new Dictionary<string, Dictionary<string, double>>(); ; foreach (var user in hours) { string department = GetDepartment(user.Key); if (!temphours.ContainsKey(department)) { temphours.Add(department, new Dictionary<string, double>()); } foreach (var customerReport in user.Value) { if (!temphours[department].ContainsKey(customerReport.Key)) { temphours[department].Add(customerReport.Key, 0); } temphours[department][customerReport.Key] += customerReport.Value; } }

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  • Databinding question: DataGridView <=> XDocument (using LINQ-to-XML)

    - by Pretzel
    Learning LINQ has been a lot of fun so far, but despite reading a couple books and a bunch of online resources on the topic, I still feel like a total n00b. Recently, I just learned that if my query returns an Anonymous type, the DataGridView I'm populating will be ReadOnly (because, apparently Anonymous types are ReadOnly.) Right now, I'm trying to figure out the easiest way to: Get a subset of data from an XML file into a DataGridView, Allow the user to edit said data, Stick the changed data back into the XML file. So far I have Steps 1 and 2 figured out: public class Container { public string Id { get; set; } public string Barcode { get; set; } public float Quantity { get; set; } } // For use with the Distinct() operator public class ContainerComparer : IEqualityComparer<Container> { public bool Equals(Container x, Container y) { return x.Id == y.Id; } public int GetHashCode(Container obj) { return obj.Id.GetHashCode(); } } var barcodes = (from src in xmldoc.Descendants("Container") where src.Descendants().Count() > 0 select new Container { Id = (string)src.Element("Id"), Barcode = (string)src.Element("Barcode"), Quantity = float.Parse((string)src.Element("Quantity").Attribute("value")) }).Distinct(new ContainerComparer()); dataGridView1.DataSource = barcodes.ToList(); This works great at getting the data I want from the XML into the DataGridView so that the user has a way to manipulate the values. Upon doing a Step-thru trace of my code, I'm finding that the changes to the values made in DataGridView are not bound to the XDocument object and as such, do not propagate back. How do we take care of Step 3? (getting the data back to the XML) Is it possible to Bind the XML directly to the DataGridView? Or do I have to write another LINQ statement to get the data from the DGV back to the XDocument? Suggstions?

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  • LINQ Query to DataTable.DataSource

    - by lumberjack
    I am trying to perform a LINQ query on a DataTable and show the result in another DataTable. My source DataTable looks something like this: DataTable myDataTable = new DataTable(); myDataTable.Columns.Add("OrderID", typeof(int)); myDataTable.Columns.Add("Date", typeof(DateTime)); myDataTable.Columns.Add("UnitsPurchased", typeof(int)); The resulting DataTable looks like this when filled: Order ID Date Units Purchased 16548 10/15/09 250 17984 11/03/09 512 20349 01/11/10 213 34872 01/15/10 175 My current LINQ query looks like this: IEnumerable<DataRow> query = (from row in myDataTable.AsEnumerable() where row.UnitsPurchased > 200 select new { row.OrderID, row.Date, row.UnitsPurchased }) as IEnumerable<DataRow>; resultDataTable.DataSource = query.CopyToDataTable<DataRow>(); Every time I run this code query is null. I can see that that the as IEnumerable<DataRow> is the culprit, but it makes no since to me since DataTable.AsEnumerable() returns an IEnumerable<DataRow>. Any help would be appreciated.

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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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  • List Manipulation in C# using Linq

    - by Learner
    using System; using System.Collections.Generic; using System.Linq; using System.Linq.Expressions; using System.Text; namespace ConsoleApplication1 { public class Class1 { static void Main(string[] args) { List<Car> mylist = new List<Car>(); Car car1; Car car2; Car car3; car1 = new Car() { make = "Honda", id = 1 }; car2 = new Car() { make = "toyota", id = 2 }; car3 = new Car() { make = "Honda", id = 3, color = "red" }; mylist.Add(car1); mylist.Add(car2); **////mylist.Where(p => p.id == 1).SingleOrDefault() = car3;** } } public class Car { public int id { get; set; } public string make { get; set; } public string color { get; set; } } } How can I update the list by replacing the honda car of Id 1 with honda car with Id 3 in the best way.

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  • Linq join two dictionaries using a common key

    - by rboarman
    Hello, I am trying to join two Dictionary collections together based on a common lookup value. var idList = new Dictionary<int, int>(); idList.Add(1, 1); idList.Add(3, 3); idList.Add(5, 5); var lookupList = new Dictionary<int, int>(); lookupList.Add(1, 1000); lookupList.Add(2, 1001); lookupList.Add(3, 1002); lookupList.Add(4, 1003); lookupList.Add(5, 1004); lookupList.Add(6, 1005); lookupList.Add(7, 1006); // Something like this: var q = from id in idList.Keys join entry in lookupList on entry.Key equals id select entry.Value; The Linq statement above is only an example and does not compile. For each entry in the idList, pull the value from the lookupList based on matching Keys. The result should be a list of Values from lookupList (1000, 1002, 1004). What’s the easiest way to do this using Linq? Thank you, Rick

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  • Sending items in a LINQ sequence to a method that returns void

    - by generalt
    Hello all. Often while I'm dealing with LINQ sequences, I want to send each item to a method returning void, avoiding a foreach loop. However, I haven't found an elegant way to do this. Today, I wrote the following code: private StreamWriter _sw; private void streamToFile(List<ErrorEntry> errors) { if (_sw == null) { _sw = new StreamWriter(Path.Combine (Path.GetDirectoryName(_targetDatabasePath), "errors.txt")); } Func<ErrorEntry, bool> writeSelector = (e) => { _sw.WriteLine(getTabDelimititedLine(e)); return true; }; errors.Select(writeSelector); _sw.Flush(); } As you can see, I write a lambda function that just returns true, and I realize that the Select method will return a sequence of booleans- I'll just ignore that sequence. However, this seems a little bit noobish and jank. Is there any elegant way to do this? Or am I just misapplying LINQ? Thanks.

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  • Sort a List<T> using query expressions - LINQ C#

    - by Dan Yack
    I have a problem using Linq to order a structure like this : public class Person { public int ID { get; set; } public List<PersonAttribute> Attributes { get; set; } } public class PersonAttribute { public int ID { get; set; } public string Name { get; set; } public string Value { get; set; } } A person might go like this: PersonAttribute Age = new PersonAttribute { ID = 8, Name = "Age", Value = "32" }; PersonAttribute FirstName = new PersonAttribute { ID = 9, Name = "FirstName", Value = "Rebecca" }; PersonAttribute LastName = new PersonAttribute { ID = 10, Name = "LastName", Value = "Johnson" }; PersonAttribute Gender = new PersonAttribute { ID = 11, Name = "Gender", Value = "Female" }; I would like to use LINQ projection to sort a list of persons ascending by the person attribute of my choice, for example, sort on Age, or sort on FirstName. I am trying something like string mySortAttribute = "Age" PersonList.OrderBy(p => p.PersonAttribute.Find(s => s.Name == mySortAttribute).Value); But the syntax is failing me. Any clues? Thanks in advance!

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