LINQ Join Query On Datatable And Arraylist Error?
Dec 6, 2009
I have a set of LINQ queries filtering original datatable (loaded from Excel file) based on user selections in Comboboxes. Then the result is joined with Arraylist to further filter the set. Arraylist is a simple list of strings.
Query:
If (Samples.Item(0) Is Nothing) = False And Samples.Item(0) <> "All samples" Then
queryResults = From records In queryResults Join samp In Samples _
On records("SAMPNUM") Equals samp _
[Code]....
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Dec 5, 2009
I have a set off LINQ queries filtering original datatable (loaded from Excel file) according to user selections in Comboboxes. Then the result is joined with Arraylist to further filter the set. Arraylist is a simple string list from 1 to 5. [Code]
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Aug 9, 2011
I am using/creating a DataTable so the "enforceConstrains" property is not avilable for DataTable.Error message: Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.
Windows Form Load Event:
Private Sub Expenses_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
expensesGV.DataSource = listExpenses()
expensesGV.Columns(0).Visible = False
End Sub
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Jan 13, 2011
I have two DataTables:
dt1 - personid, name
dt2 - personid
I want to create a third datatable to include records from dt1 when they are NOT in dt2 using LINQ. In this case, I can bind the third datatable to a dropdownlist.
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Sep 28, 2011
I have this query that I tried to join 2 tables together, one which holds the product name, and product numbers, and take a product number, and go to the other where to find a Art_no which is like the product number.[code]
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Jul 4, 2009
I've looked all around and spent way to long trying to convert this SQL statement into a Linq statement in VB. I'm sure it would be a good example for others out there - the statement is trying to pull products that have a many-to-many relationship with product categories, and the categories have a hierarchy of parents/children.
Here is the query I am trying to convert:
SELECT P.ProductID, P.ProductName, P.ProductSlug, P.PartNumber
FROM Products AS P
INNER JOIN Products_Categories AS PC ON PC.ProductID = P.ProductID
[code]....
I can get up to the point where I am trying to say "WHERE ... (P_Cats.Parent = 9)" but can't figure that part out.
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Aug 6, 2010
Given a table like
ID | Name | City
1 | X | Y
2 | Z | Y
[code].....
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Apr 17, 2011
How to JOIN tables on nullable columns? I have following LINQ-query, RMA.fiCharge can be NULL:
Dim query = From charge In Services.dsERP.ERP_Charge _
Join rma In Services.dsRMA.RMA _
On charge.idCharge Equals rma.fiCharge _
Where rma.IMEI = imei
Select charge.idCharge
I get a "Conversion from type 'DBNull' to type 'Integer' is not valid" in query.ToArray():
Dim filter = _
String.Format(Services.dsERP.ERP_Charge.idChargeColumn.ColumnName & " IN({0})", String.Join(",", query.ToArray))
So I could append a WHERE RMA.fiCharge IS NOT NULL in the query. But how to do that in LINQ or is there another option?
The problem was that the DataSet does not support Nullable-Types but generates an InvalidCastException if you query any NULL-Values on an integer-column. The modified LINQ-query from dahlbyk works with little modification. The DataSet generates a boolean-property for every column with AllowDbNull=True, in this case IsfiChargeNull.
Dim query = From charge In Services.dsERP.ERP_Charge _
Join rma In (From rma In Services.dsRMA.RMA _
Where Not rma.IsfiChargeNull
Select rma)
On charge.idCharge Equals rma.fiCharge _
Where rma.IMEI = imei
Select charge.idCharge
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Jan 29, 2012
I'm working on an ASP.NET 4.0 site, which I inherited ownership of. It has a number of existing LINQ datasources pointing to individual tables. For example, to the Patient Encounter Summary table in SQL Server. The problem is in displaying the data there. It's a normalized database, so that table contains (for example) the provider ID, rather than the provider name.
It's simple enough to join the Patient Counter Summary to the Providers table (in SQL)... but how does one do that in ASP.NET? I'm not sure of the correct nomenclature, but the 'mid layer' is VB.
[Code]...
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Jun 6, 2011
I dont have a huge wealth of experince with SQL statements and im struggling;
[code]...
I would like to list all of the job titles(for which there could be multiples as different employees can have the same job title) in the employee table and find the maximum amount of hours for that job title as the hours could be different for different empoyees.
[code]...
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Jun 1, 2012
I'm having a hard time joining 2 datatables and have the joined datatable as result. First datatable (labels) holds data including a printerid. Second datatable (printers) holds printer references (id > unc). I would like to have as endresult (joined) a datatable with all data from the first datatable with the field (unc) of the second datatable. [Code]
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Jul 20, 2010
How can i write this query with LINQ to a FoxPro database?SELECT count(*) FROM Table group by item1I wrote it as below, but it doesn't work
Dim Query
Dim dt As New DataTable
Dim da = New Odbc.OdbcDataAdapter("SELECT * FROM table1",connection)
[code].....
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Feb 18, 2010
I have an SQL table(for example, it have 1 column "kod" with 3 rows:1,2,3 ). To operate it, I used class LINQ to SQL and I create tmp dataset with one table, with one column "col" with values - 2,3,4. To operate with this tmp table i use IEnumerable(T).I want to find only new values in tmp table and write its in SQL table. To find this values, i want to use LINQ query. Queris to each table are worked well. But query for 2 tables don't work.
Imports System.Linq
Imports System.Data.Linq
Public Class Form1
[code]....
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Nov 7, 2011
i need to query the datatable & set the outcome as datagridview controls datasource
vb.net
Private Sub Txt_Search_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Txt_Search.TextChanged
'routine objective:- Filter datatable & set the datagridview datasource
[code]....
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Jan 25, 2010
I'm trying to do a LINQ Query against a typed datatable that will return me duplicated data.With out going into too much detail, here's the basic setup:
strCode1 - string type
intCode1 - int32 type
intAdjustor - int32
There are more fields but these are the ones that are important.I'm going to do my best to describe this, as it's kind of confusing.In theory intCode1 is a key for strCode1 (hence the names). So each time intCode1 is duplicated, the same strCode1 should appear. Example:
[code]...
Ultimately I'd like to get a List(Of T) - where T is my typed data row. In SQL, I would simply use a sub query, to get a distinct list of strCode1 and intCode1, then do a count, grouped by strCode1 where I get more than one row.I'm not sure how to translate that into LINQ, AND get the original types data rows returned in a list.
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Jan 23, 2009
Why does the following code give an error?
[Code]...
If I change the code to remove the second field, as below, then the code does not give an error.
[Code]...
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Jan 14, 2011
I 've an ArrayList and to join all its elements with a separator in one string I m using...
Dim s As String = String.Join(",", TryCast(myArrayList.ToArray(GetType(String)), String()))
however, I would know if there is a smarter/shorter method to get the same result,or same code that looks better...
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Feb 28, 2012
I am trying to write a LINQ query with a Join in it, using VB on .NET 4.0.
I get the red squiggle under my line of code and when I mouse over it, it shows:
"Cannot not transform LINQ"
Note the double-negative.
Grammatically it would mean there is NO error, but I don't know why there should even be an error message then. This "error" also kills auto-complete on the line in question, as if there actually IS an error.[code]...
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Sep 21, 2010
If txtSearchString.Text.Trim <> "" Then
Dim searchString As String = txtSearchString.Text.Trim
Dim results As EnumerableRowCollection(Of DataRow) = From PO In FilterPurchaseOrders().AsEnumerable
[CODE]..............
I am getting this error: error BC30205: End of statement expected.
FilterPurchaseOrders() function returns a datatable.
Whats wrong with the above code?
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Feb 22, 2012
I have a List of Price Objects (Price contains Date, High, Low) and am trying to extract monthly averages via LINQ. I have this working in C# but we have a few legacy applications that need it in VB.Net and I can't quite seem to figure out the conversion. I've even tried breaking it into two queries to no avail.
[Code]...
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Jul 4, 2011
Following is the code I get to achieve a list of Courses:
Dim Result As New List(Of WorkMateLib.CourseNameSpace.CoursesLib.Course)
For Each cat As WorkMateLib.CourseNameSpace.CoursesLib.Category In Courses.CoursesOfferedMAIN.Values
For Each c As WorkMateLib.CourseNameSpace.CoursesLib.Course In cat.Courses.Values
Result.Add(c)
Next
Next
and it is working fine. However I am trying to attempt to do the same with linq and the code is:
Result.AddRange(From k As WorkMateLib.CourseNameSpace.CoursesLib.Category In Courses.CoursesOfferedMAIN.Values Where Not k.CategoryName = "" Select k.Courses.Values.ToList())
[Code]...
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Aug 23, 2011
My 1st DataTable TableA
[Code]...
But I am not Getting the Proper Output
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Sep 16, 2010
I'm developing in MVC2 using VB.NET and MySQL and ran into a problem trying to convert a simple SQL query to LINQ. SQL Query:
[Code]...
Looking at that query its easy to spot whats causing the error. Simply, the most inner query only returns 2 columns, while the query right above it is trying to SELECT 3, thus the Unknown Column Error. So why is this happening? What is wrong with my LINQ query?
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May 22, 2010
I created a datatable from ado.net, myDatatable. Is it possible to make inner join on myDatatable from a select statement, like below?
select * from order o inner join on o.productID = myDatatable.productID
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Sep 22, 2009
I know that LINQ queries are deferred and only executed when the query is enumerated, but I'm having trouble figuring out exactly when that happens.Certainly in a For Each loop, the query would be enumerated.What's the rule of thumb to follow? I don't want to accidentally enumerate over my query twice if it's a huge result.
For example, does System.Linq.Enumerable.First enumerate over the whole query? I ask for performance reasons. I want to pass a LINQ result set to an ASP.NET MVC view, and I also want to pass the First element separately. Enumerating over the results twice would be painful.It would be great to turn on some kind of flag that alerts me each time a LINQ query is enumerated. That way I could catch scenarios when I accidentally enumerate twice.
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Jul 6, 2009
I have a DataGridView that is bound to a list of objects called "BaseChange". The BaseChange objects are made up of 4 properties...
ChangeType
ChangeStatus
ChangeDescription
LastChangeDate
The datagridview has columns for all 4 values as well as a 5th (a checkbox column called "colIsSelected"). There is no problem binding the list to the grid and displaying the items. The problem is that the query that gets the selected items in the grid is giving me an implicit cast error when option strict is enabled.
This is the query...
Dim _changes As List(Of BaseChange)
_changes = (From _row As DataGridViewRow In dgvChanges.Rows() _
Where Convert.ToBoolean(_row.Cells(NAME_COLUMN_IS_SELECTED).Value) = True _
Select DirectCast(_row.DataBoundItem, BaseChange)).ToList()
...and it produces the correct results with option strict off. The implicit cast squiggle is on the "row As DataGridViewRow" code, and the full message is "Implicit conversion from 'Object' to 'System.Windows.Forms.DataGridViewRow'*".
If I exclude the "As DataGridViewRow" from the query, I get a late binding error on the _row.Cells and _row.DataBoundItem and this also fails option strict.I need this to work with Option Strict enabled, and in VB.
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Nov 30, 2011
I have a strongly typed DataTable in my app which is generated with a couple of SQL joins. I use it to display data in a human readable way.[code]....
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Apr 15, 2011
I'm trying to join two datatables of same keyfields.
table1
ID Class
---- -----
1 10
2 9
[code]....
Result
ID Class1 Class2
1 10 8
2 9 7
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Apr 23, 2009
Given two tables, customer and orders, how would one do a linq query to entities to find any customers with open invoices started before a certain date?
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Jun 16, 2009
Are the below two queries functionally the same?The first one doesn't return any data, but the second works fine with same exact input.Can someone point out what's wrong in my first query? [code]
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