linq-to-dataset

LINQ - How can I use DataSet.DataRelation to join these tables and sum one field?

My LINQ query is not producing the expected output below. Basically, it's the sum of table3.cost corresponding to table2.code and table2.class categorized by table1.alias and ordered by table1.priority. I added two DataRelation's to the DataSet: ds.Relations.Add("Table1Table2", ds.Tables[1].Columns("ID"), ds.Tables[2].Columns("ParentI...

Binding LINQ query to DataGridView

This is very confusing, I use AsDataView to bind query result to a dgv and it works fine with the following: var query = from c in myDatabaseDataSet.Diamond where c.p_Id == p_Id select c; dataGridView1.DataSource = query.AsDataView(); However, this one results in an Error: var query = from item in myDatabaseDataSet.Items where it...

LINQ to DataSet - group by variable field, or join on a variable condition (with sum)

The following query works as long as I can add DataRelations. However, the relation "Table2Table3" may no longer be clearly defined, so I think I need to remove it. The old relation strictly joins on 2 string fields. The new relation exists if Table2.code = Table3.code and Table2.class = Table3.class OR Table2.code = Table3.code and Tabl...

Slow Update/insert into SQL Server CE using LinqToDatasets

I have a mobile app that is using LinqToDatasets to update/insert into a SQL Server CE 3.5 File. My Code looks like this: // All the MyClass Updates MyTableAdapter myTableAdapter = new MyTableAdapter(); foreach (MyClassToInsert myClass in updates.MyClassChanges) { // Update the row if it is already there int result = myTableAd...

Is LINQ to Dataset subset of LINQ to EF or these two are independent?

Is LINQ to Dataset subset of LINQ to EF or these two are independent? ...

grouping data from two dataset

hi, i've got a problem with dataset: I've got two dataset from two different server but they have the same columns. so it's like that: First DataSet : asset description make jobtype jan feb ... dec 0001 mine ik Acc 0 0 10 0002 yours ic Over 0 0 10 Second dataset : asset description make ...

Why doesn't EnumerableRowCollection<DataRow>.Select() compile like this?

This works: from x in table.AsEnumerable() where x.Field<string>("something") == "value" select x.Field<decimal>("decimalfield"); but, this does not: from x in table.AsEnumerable() .Where(y=>y.Field<string>("something") == "value") .Select(y=>y.Field<decimal>("decimalfield")); I also tried: from x in table.AsEnumerable() .Where(y=...

Store an image in a SQL Server CE database

Does any one know of an example on how to store an image in a SQL Server CE database? What data type should the column be? (I am guessing binary.) I use Linq-To-Datasets. Is it possible using that to put the image into the database and pull it out again later? Thanks for any advice. Here is how I did it: MemoryStream stream = ne...

Getting minimum - Min() - for DateTime column in a DataTable using LINQ to DataSets?

I need to get the minimum DateTime value of a column in a DataTable. The DataTable is generated dynamically from a CSV file, therefore I don't know the name of that column until runtime. Here is code I've got that doesn't work... private DateTime GetStartDateFromCSV(string inputFile, string date_attr) { EnumerableRowCollection<Data...

LINQ to Object to DataSet

Can I do a LINQ Join from an List to a DataSet? Are there any caveats to doing this? ...

Issue with DBNull when using LINQ to DataSet

I've got the following LINQ Statement: Dim PSNum As Integer = 66 Dim InvSeq = (From invRecord In InvSeqDataSet.RptInvSeqDT.AsQueryable() _ Where IIf(invRecord.IsPack_NumNull(), False, invRecord.Pack_Num = PSNum) _ Select New With _ {.Inv = invRecord.Invoice_Num, .Seq = invRecord.Inv_Seq})...

Using LINQ to fetch result from nested SQL queries

This is my first question and first day in Linq so bit difficult day for me to understand. I want to fetch some records from database i.e. select * from tblDepartment where department_id in ( select department_id from tblMap where Guest_Id = @GuestId ) I have taken two DataTable. i.e. tblDepartment, tblMap Now I want to fe...

When using Query Syntax in C# "Enumeration yielded no results". How to retrieve output

I have created this query to fetch some result from database. Here is my table structure. What exaclty is happening. DtMapGuestDepartment as Table 1 DtDepartment as Table 2 Are being used var dept_list= from map in DtMapGuestDepartment.AsEnumerable() where map.Field<Nullable<long>>("GUEST_ID") =...

Why I am getting Null from this statement. Query Syntax in C#

This is not working. Returns Null to dept_list. var dept_list = ((from map in DtMapGuestDepartment.AsEnumerable() where map.Field<Nullable<long>>("Guest_Id") == 174 select map.Field<Nullable<long>>("Department_id")).Distinct())as IEnumerable<DataRow>; DataTable dt = dept_l...

I want to get 2 values returned by my query. How to do, using linq-to-entity

var dept_list = (from map in DtMapGuestDepartment.AsEnumerable() where map.Field<Nullable<long>>("GUEST_ID") == DRowGuestPI.Field<Nullable<long>>("PK_GUEST_ID") join dept in DtDepartment.AsEnumerable() on map.Field<...

Update/Insert to a table using SQLCeResultSet

I have a SQL Compact Edition Database that I update periodically (via web services). The part where I write to the database is taking way too long. I am currently doing it with Linq to Datasets (as seen in this question). I have heard that if I do it with with SQLCeResultSet that it will work faster. So, given that I have a table lik...

Select distinct rows from datatable in Linq

I am trying to get distinct rows based on multiple columns (attribute1_name, attribute2_name) and get datarows from datatable using Linq-to-Dataset. I want results like this attribute1_name attribute2_name -------------- --------------- Age State Age weekend_percent Age statebreakl...

Syntax for LINQ to DataSets Row Filter in C#?

I have two DataTables one is Primary Table and the rest is a sub table (I AM UISNG STRONGLY TYPED DATASET). Example Employee Table Id Name City 1 AAA NY 2 BBB BB 3 CCC AA CityInitials Table CityInitial NY FF CC RR RNF YOT DDD I have to select rows from employee table only when the 'city' in Employ...

not able to use CopyToDataTable in linq for returning dataset

how to return a dataset from linq in .net 3.5? I have seen in some sites that CopyToDataTable method is used but I am not able to use that methos as I cannot find System.data.datatableextensions reference in the ref list. Please help me out. Thanks and regards, veena ...

Copying Result of Linq into DataTable

What changes do i need to make so as to reduce of doing this task with fewer lines and better approach. DataTable dtStatusMsgs; var statusList = ( from items in dtInputTable.AsEnumerable() where items.Field<int>("DepartmentId") == deptId select new { ...