I would like to implement a generic Linq query on a DataGridView.DataSource to retreive a row whith an idField. I did search MSDN, StackOverflow, etc... but didn't quite find what I'm looking for. how I could implement it ?
This is the non-generic code, but I would like to make it work whatever the type of the DataSource is (as long as it implements IEnumerable I guess) and the name and type of the key field.
Dim query = (From note In notesList _
Where note.IdNote = mIdNoteSelectionne _
Select note).FirstOrDefault()
Dim ancienIndex As Integer = notesList.IndexOf(query)
noteList is a List(Of Note), Note is a simple entity class I created, with just members and properties
This is in VB, but feel free to send some C# code, I'll translate it.
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
i am trying to read a csv file and then query it using linq and thereafter bind the query result to a datagridview. similiar code works fine when querying a database but not when using the csv file. the file import works fine but the result on the datagridview is the lenght of the strings of each year, nav and return. how do i get the real values and not the information of the lenght of the values.
I have a VB.NET search routine, part of which is provided, below, that checks all Text cells in a DataGridView for a given string (inclusive), using a basic set of nested loops to perform the search:
' Search for the first occurrence of the given string For Each row As DataGridViewRow In dgvMembers.Rows ' Skip the new row
[Code].....
is there a way to replicate this behavior using LINQ? Basically I would like the query to select (or return) the first DataGridViewCell whose text contains the search string. I've done some tinkering with sub-queries and the like, but I'm still having trouble wrapping my brain around the concepts (too many years of writing T-SQL, I guess).
I am using a modal form with a datagridview in order to populate textboxes on a parent form. The datagridview is bound to an anonymous type resulting from a linq query, which varies depending on the textbox control whose keypress event is called. I always want to display a key value in column 0 of the datagridview (along with a variable number of additional columns), and then use that key value once the user selects a row.
However, when setting an anonymous type from a linq query as the datasource for a datagridview control, the columns are indexed alphabetically rather than in the sequence selected in the query. This requires setting the displayindex as a workaround, and then keeping track of which column contains my key value. I read elsewhere that this was something fixed in VS2008 SP1, but I still encounter the behavior.
I'm using a DataGridView to post the results of LINQ-from-SQL query. I was hoping that the data would be editable in the DataGridView, but it isn't. I made sure that DataGridView.readonly = false. I'm using VB.
VB 2008 DB = New CXToolDataContext() Dim Systems = (From TBLSYSTEMS In DB.tblSystems, TBLSYSTYPES In DB.tblSystemTypes _ Where TBLSYSTEMS.ProjectName = projectnumber And TBLSYSTEMS.SystemType =
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.
I have to join two main tables, and I need to filter the results by elements in an ASP.NET web form. These filters are created on the fly so I have to use a lot of where extensions to filter the query. I want to execute the query with as optimized SQL as possible.
I am first doing a simple join between TW_Sites and TW_Investigators. Then there are two sub-tables that are involved. TW_InvestigatorToArea and TW_InvestigatorToDisease. While most of the where clauses are working fine, I have found a performance issue that won't be an issue right now, but will be an issue as the table gets bigger.
The arrays DiseaseCategories and DiseaseAreas would be the results of a CheckBoxList result.
Protected Sub LoadResults() 'Get Dictionary of Filters Dim FilterDictionary As OrderedDictionary = Session.Item("InvestigatorFilterDictionary") ' Initialize LinqToSql
As I am beginner in LINQ, I have small problems. I have dictionary of Char and Long, and I would like to use LINQ to retrieve Char with highest Long Value. I saw some C# samples, which look pretty easy, but I can't achieve such expression in VB.Here are two expressions, and I don't think they are most efficient possible.
i am building a database application in vb.net and i started by adding a data source from the DATA in the toolbar. my connection is good and it shows all my tables in the data source panel.
i also see new classes related to my database, like
sakilaDataSet sakilaDataSet.customerDataTable ... and so on.
how do i query and use these ? i googled a lot and i am not able to get this.
Dim cust As sakilaDataSet.customerDataTable = New sakilaDataSet.customerDataTable Dim row() As System.Data.DataRow = cust.Select("customer_id=5") MsgBox(row.Count)
My last try was with the above code, but the row.count always turns out to be zero.
OK So I know WHY I am having the error I am getting. I don't know HOW to fix it. Basically, if the user doesn't have a certain permission, I need to join another table. But .NET is so picky I can't just make two different queries in an IF statement and then use it outside of the if statement. I can think of some ugly work arounds for this, but I would rather not. I am fairly new to .NET I know just enough to be dangerous.
[Code]...
because of this: Dim l As IEnumerable(Of Company) its not just IEnumerable of a Company, its got the source in it. I have to explicitly select source to use it in my datagrid. Can I make Dim l something that will make it stop complaining?
If I used a generic list Class to hold data objects that I am pulling from SQL Server using Linq to sql to populate a datagridview would I need to make any modifications to the datagridview control to accomodate multiple columns or would I need to make any modifications to the generic list class to accomodate the multiple columns in a row that is typical of a record in SQL Server? And one more thing which I believe is the easy part. To bind the list to a datagrid view would I just use the datasource property of the datagridview control.
I am trying to learn some VB.NET for my coo-op that starts next week, and for that reason i took my portfolio web site that is on C# and just started to converting it to VB.NET to get familiar with the syntax.
I am sure my problem is simple however i have a hard time solving it. I am trying to grab data with the linq query and then return it as list to bind to the Repeater.I have the following function:
[Code]...
And it would work fine. However if I try to use ToList() in VB.NET i am getting error that it cannot convert it from ling to sql List to the generic list. How do i do this convertion in VB.NET ? or maybe there is another way ?
I am decent when it comes to C# however somewhat lost with the VB.NET syntax.
I need to take a collection and group it via Linq but all the examples I've seen fail in some manner or other with some syntax difference that I can't quite lick.
My collection:
Dim a As New List(Of ProcessAlert) a.Add(New ProcessAlert("0000112367", "5551110000@txt.att.net", "Alert", 2)) a.Add(New ProcessAlert("0000112367", "5551110000@txt.att.net", "Document", 2))
Forgive my ignorance on this.I have this LINQ Query:Dim ngBikersDataContext As New CarBikeWalkDataContext
bikersList = (From c In ngBikersDataContext.Reg_Bikers _ Order By c.L_Name _ Select New Bikers() With { _ .BikerID = c.BikerID, _ .F_Name = c.F_Name, _
[Code]...
with the error "Overload resolution failed because no accesible 'Select' accepts this number of arguments." Over the "NEW" I get an error " ')'expected."
I have several problems with rows in a DataGridView. Background information: The DataGridView (DataGridViewCalib) is in one TabPage of a TabControl, some columns of the DataGridView are automatically DataGridViewCheckBoxColumn as the DataSource have some colums which are Boolean. This is a Windows Form written in VB.Net with Visual Studio 2008. The user loads an input data file.
The problems:
1) At first arrival in the TabPage, ShowDataGridViewCalib (code below) is called. All rows are then shown in the DataGridView, despite the code saying that some rows should not be visible. Breakpoints in the code show that the code do arrive at the Rows.Visible = False events. Despite all rows beeing shown a Watch in the debugger shows that:
[code]...
There are two alternative ways of handling the rows in the code. The first attempt (commented away here) is probably the "nicest".
I have a function that works great in C# that I'm converting to VB.Net. I'm having an issue converting the result set to a generic list in VB.net.
The code:
Public Function GetCategories() As List(Of Category) Dim xmlDoc As XDocument = XDocument.Load("http://my_xml_api_url.com") Dim categories = (From category In xmlDoc.Descendants("Table") _ Select New Category()).ToList(Of Category)() Return categories End Function
The error occurs when convertng the result via .ToList(Of Category)() The error:
Public Function ToList() As System.Collections.Generic.List(Of TSource)' defined in 'System.Linq.Enumerable' is not generic (or has no free type parameters) and so cannot have type arguments.
Category is a simple object I've created, stored in the App_Code directory.
I have the necessary "Imports System.Collections.Generic" reference in the file so I don't see why I can't convert the result set to a generic list.
My program needs to create a mailmerge with Word using a specific group of clients from the sql database list. I have a datatable set up in the database that stores the clients information on the individual user's computer.
The code below will automate word to create the mailmerge, but I can't figure out how to pull the following from my client table and use the results as a mailmerge datasource[code]...
I wrote the following generic LINQ extension for calculating weighted average in Visual Basic 2010: <Extension()> Function WeightedAverage(Of T)(ByVal source As IEnumerable(Of T), ByVal selectorValue As Func(Of T, Integer), ByVal selectorWeight As Func(Of T, Integer)) As Double Dim weightedValueSum As Double Dim weightSum As Integer [Code] .....
How can I call this function as an Aggregate function of another LINQ query? I tried it in the following way: Dim q1 = From jd In oContext.JobDatas Where jd.Year = 2011 Select jd Dim q2 = Aggregate num In q1 Into WeightedAverage(num.AvSalary, num.NumPosHolder) The Visual Basic 2010 editor is telling me that the second query (q2) of the following code is not valid statement. On the comma between the first an second argument it's saying: ")" required.
Dim tenItem = From t In _InvalidFeeList _ From i In ItemCount _ Where t.FeeCode <> i.FeeCode _
[Code]....
I am getting "Can not convert to System.generic.list" error. I look all over for this error and it seem like my code should work for example here
edit: I think i should explain what I'm trying to do here. I want to compare two object list and select the object from the InvalidFeeList if the FeeCode is not equal to the object in ItemCount FeeCode and take the first 10 objects from the InvalidFeeList.
I have been writing same code for insert, update, delete with LINQ over and over again. I want to have some sort of generic function for Insert, Update, Delete operation. I read a post here like the following :
public static void Insert<T>(T entity) where T : class { using (OrcasDB database = new OrcasDB())
This is really a continuation from my earlier post. I've never worked with this datatype/collection (system.collection.generic.Ienumerable) before so I'm struggling to declare the query globally so I can reference the results within other sub routines/functions. I also am struggling to convert it to other types.how I can convert the collection of xml elements/system.collection.generic.Ienumerable into an xmltextreader (I know I will have to change the query below as it select the value of the node and not the node itself) I imagine by converting the query result to system.IO.stream My first port of call was MSDN but I find the material very difficult to understand for this particular subject.
We are doing a query against an in-memory collection of LINQ data objects. The wrinkle is that we are ordering by a column in a related table whose records have not necessarily been loaded yet (deferred loading:)
Dim oPkgProducts = _ From b In oBillPkg.BillProducts _ Where b.Successful.GetValueOrDefault(Common.X_INDETERMINATE) = _
My application must display some data in Datagridview (status of COM ports communication) and i Used .mdb databases before for faster search and Datagridview update. How i understand Datagridview is importing data from DataTable and data in DataTable is imported from .mdb file, so i decided to make shortcut - stop to using .mdb file (data must be erased every time application start and it is useless make .mdb file and erase it every time, becouse it is increasing even when drop is used) and using only DataTable..
I want to row in Datagridview change it color to red when it's Collumn(6).text countains %error% string..
When Error in COM port is starting, i can fast find row in DataTable for that port and write information that Error accured for that port and DataGridview automatically updates:
Dim RRow as () DataRow RRow = ds.Select("Port = 'COM3') RRow(0).Item(6) = "Error Opening COM3"
