C# - LINQ - Select All In Parent-child Heirarchy
Mar 12, 2012
I was wondering if there is a neat way do to this, that DOESN'T use any kind of while loop or similar, preferably that would run against Linq to Entities as a single SQL round-trip, and also against Linq To Objects. I have an entity - Forum - that has a parent-child relationship going on. That is, a Forum may (or in the case of the top level, may not) have a ParentForum, and may have many ChildForums. A Forum then contains many Posts.
What I'm after here is a way to get all the Posts from a tree of Forums - i.e. the Forum in question, and all it's children, grandchildren etc. I don't know in advance how many sub-levels the Forum in question may have. (Note - I know this example isn't necessarily a valuble use case, but the Forum object model one is one that is familar to most people, and so serves as a generic and accessible premise rather than my actual domain model.)
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Aug 23, 2010
I have two tables Employees and CafeLogs. Some employees can be cashiers and also customers at the Cafe shop.
Table structures:
Employees: EmployeeId(PK) , FirstName, LastName
CafeLogs: LogId (PK), CashierId, EmployeeId, Value, => CashierId and EmployeeId are the data from column EmployeeId of Empoyee table
Table relationship:
Employees 1:N CafeLogs (CashierId (FK))
[code]....
Right now I know how to select only LogId, Employee's name, and , Value, not with Cashier name yet.
Dim query = From log In db.CafeLogs _
Join emp In db.Employees On emp.EmployeeId Equals log.EmployeeId _
Select log.LogId, emp.FirsName, emp.LastName, log.Value
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Jul 9, 2010
I have a table (Projects) which is linked to projectVersions on projectID..projectVersions contains several columns on which I'd like to filter a returned project (and associated projectVersions) list. For example there is a "capacity" column and a "country" column. I am doing a filtered list of projects on one page and I'd like to include all projects where any one of the associated projectVersions has a capacity of 750ml and a country of "France" for example.It may be that a particular parameter is not set and so I pass a zero to indicate not to filter on that.I guess this needs some kind of subquery as when I try and do something like this: [code] it doesn't work as the "xxx" bit, being one-to-many, expects me to specify an item to get at the entities within and yet I want to query where ANY of the associated versions match one of the criteria.
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Sep 18, 2009
I'm having a nightmare with LINQ. I've got a table of Projects, and each project has many InvoiceHeaders. The Invoice header had a field AmountNet - the value of the invoice.
I want to retrive, for arguments sake, all of the fields from Projects, with the count of invoice headers and the sum of AmountNet. I.e. list of my projects, how many invoices I've raised and the value.
Doesn't sound hard does it.... well, I've just spent the best part of two hours charging through Google and SO to find a solution.
[Code]...
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Jan 12, 2012
I have a parent child collection objects and was wondering how to get a single item from the child collection using Linq
[Code]...
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Feb 18, 2011
Im working with MDI parent/child objects. when closing the child objects i need the child to check to see if it is the last child object before closing. i couldn't find anything on google, maybe im searching for the wrong thing.
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Feb 3, 2010
Basically, I am trying to write a LINQ to Objects statement where the relationship is a grandparent, parent, child relationship. (You could also call it a Master Detail relationship.)
Dim coverages As New List(Of Coverage)
Dim coverage As Coverage
For Each rl In oClaimsPolicy.RiskLocations
[code].....
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Jun 24, 2009
I have a main form, and some sub forms, and each sub form can have some sub forms. When I have multiple sub forms open, and I try to get data from the parent form, it returns the data from the wrong parent form.For example I have two instances of Mainform.subform running. If I do something like this in a child form of one instance of the subform. It returns data from the other subform.
dim l = Mainform.subform.listofdata
Edit:I am using visual Studio 2008. Winforms, form designed using designer. In my mainform I am doing this
Protected Friend frmMain as Mainform
frmmain = new mainform
In frmMain I am doing this
Protected Friend frmsub as new Subform'
frmsub = new subform
[code]....
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Apr 10, 2010
I would like to know if there is some simple code to release a child control from it's parent control, without having to name the parent control. In pseudocode, I'm looking for something like this:
[Code]...
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May 21, 2012
Dim obj_DataTable As New System.Data.DataTable("Category")
Dim obj_DataSet As New DataSet()
'Declaring the array of DataColum to hold the Primary Key Columns
[code].....
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Apr 28, 2009
Applications_Type is a lookup table for Applications.What I am trying to do is provide a drop down list of applications and a label that displays the selected application type.[code]...
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Apr 10, 2011
i have created two forms A and B when button in form A is clicked B is invoked when B is running its not possible to work on A until i close form B. How can i work on A without closing B
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Apr 17, 2012
i have three forms
when i click button1 on form1=====> form2.showdialog()
then click button 1 on form2 =====> form3.showdialog
then click button 1 on form 3 =====>
[code].....
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Oct 12, 2011
I have a listview "CategoriesList" and i have a repeater "NewsRepeater" inside the listview "CategoriesList"
<asp:ListView ID="CategoriesList" runat="server" DataKeyNames="CatID" DataSourceID="CategoriesListODS"
EnableModelValidation="True">
[Code]....
how to pass the catID from the listview and make it as SelectParameters in ObjectDataSource "NewsRepeaterODS"?
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Nov 12, 2010
Note: I am working with Visual Studio 2010 Professional. Note: There are a lot of MDI Child posts, but none (that I have found) that apply to my scenario... Scenario I have an MDI form with a UserControl docked at the top. The UserControl is for navigation and is ~50 pixels in height. When I show a child form with its WindowState property already set to 'Maximized', the child form shows maximized in the MDI parent, but behind the UserControl.
[Code]...
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Dec 17, 2009
I have created a simple application. It contains one MDI parent and one child of its. At load of MDI parent i have also loaded its Child. but problem is with its display. the images of output is attached. Form2 is MDI Parent and Form1 is child.
The code at load of Form2 is:[code...]
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Jun 27, 2012
I have 2 pages. parent.aspx and child.aspx. In parent.aspx, i use colorbox and send some value for the child.aspx to popup.
[code]...
child.aspx will popup and shows ASPxGridView base on the value passing from parent.aspx. User will select the data from ASPxGridView. the selected data need to send back to the parent page. I code it in child.aspx.vb page.My problem is how can i get the value from child.aspx.vb and pass it to parent.aspx ?
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Feb 19, 2009
I have a simple contact book. The application has a main window that's an mdi form. When a contact is added using the "add a contact" form, I want to show a simple feedback message in the parent window status bar saying that the contact was added successfully. Here's the child loading:
[Code]....
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Jul 28, 2010
I am trying to size an MDI form to fit its 2 children perfectly within itself but when I use simple sizing it doesn't work - the MDI form always introduces scroll bars and the children seem to be too big for the parent. My three mDI form methods where this occurs is below.
Private Sub positionSyncForm()<br/>
With m_SyncManager<br/>
.Top = 0<br/>
[Code].....
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Nov 2, 2010
I have 2 tables with relation from parent table (customers) and child table (orders) and i have all inside typed dataset.
Now i want a field of customers by datarelation from field child table.
Inside child table i have IDCustomers and i want Customers.FirstName
I think so, inside databinding form designer, inside Text i write
dsMaster.Orders.CustomersOrders.FirstName
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Feb 24, 2009
I have two datatables inside a single dataset (all are typed). dtOriginalData contains roughly 25 or so fields, which included IDs, descriptions and other bits of data. The ID is the PKey in this case. dtEditData contains almost the same columns as the first,with a couple of extras thrown in. One of the fields in dtEditData is the ID from dtOriginalDatafter the two tables are loaded, I create a datarelation between the two using this ID field. I then update some of the fields in the dtEditData and set their expression to pull data from the Parent table (dtOriginalData) ... this is then fed to a grid. So far everythign works fineNow I need to add some functionality, displaying the Original Data, the Edited Data and the variances between the two.
The bindingContext is set cocrrectly. I've successfully bound all of the edited fields to their appropriate labels, and everything updates as I scroll through the data in the grid.It's all fine and dandy... except.... for the Original Data fields... I bound them to dtOriginalData.... and all I get is the first record displaying. It's not taking into consideration the relation between the two databases and advancing the index on it. So, what I need to find out, is if there is a way to do the databindings so that the two data tables will move in synch with each other, keeping the displayed values updated with the correct information. If, for some reason I can't find a way, I may have to resort to a gawd awful datatable with 30+ fields in it.
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Dec 13, 2011
May I know is there any solution for both MDI parent and MDI child is MDI form?I am trying to set like this.
uiAdjustment.MDIParent = Me uiAdjustment and "Me" is both MDI form and it show error when I am trying to do like this.
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Feb 11, 2010
I'm just getting started in VBE 2008 porting a VB6 program and have created the MDI Parent form. I've added a form called frmNav and need to designate this and all subsequent forms as MDI child forms. Is there somewhere in each form's properties where I designate this? It used to be in VB6 there was a property called "MDIChild = True." input id="gwProxy" type="hidden"><!-- Session data--></input> <input id="jsProxy" onclick="jsCall();" type="hidden" />
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Jan 23, 2010
I have a regular form that I have a SplitContainer on and I would like to launch an external program (not mine) in Panel2, maximize it to fill the whole panel, and hide it's toolbar if possible. The program I am launching is a monitoring program of network activity. To be even more detailed, it is a puTTy window that opens a telnet connection to a server. I need to launch this putty window in Panel2, and then maximize it so that it cannot be resized/dragged.
[Code]...
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Jan 31, 2011
I am trying to access a control (statusbar panel) on my MDI parent form from a child form.
Here's my
(located in child form)
Dim frmParent As frmMain
frmParent = DirectCast(Me.MdiParent, frmMain)
[Code]....
Object reference not set to an instance of an object.
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Jul 13, 2011
Working on an VB/ASP website in Visual Studio 2008. Getting the error "You cannot add or change a record because a related record is required in table 'abc'
It is true that table xyz (the target of the INSERT) is in a parent-child relationship with table abc. The PK in abc is a column RequestID_lng. The FK column in xyz is also named RequestID_lng
This is the only relationship these 2 tables are in.
I am trying to add a row in xyz with a value of 45 in the FK. There is already, previous to this action, a row in table abc with a value of 45 in the PK. So the parent already exists for this child.
I have used the watch window to copy my SQL code for the INSERT query that is being executed. I pasted that code into a new query in the Access DB and executed it without problem - it actually added the row that .Net should have.[code]...
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Oct 5, 2009
I have been looking around at how I can close my parent form and my child form. This article: [URL] has some information but it either doesn't work for me or I am putting the wrong information it. What I want to happen is when a button is pressed I want to close both parent and child forms and then go to another form (frmResults). Then there will be a button on frmResults that will take me to the beginning form (frmPTCalculator). With this code below when I click the button on frmCalculator it goes to the MDI form and both parent and child forms are there.
my Parent form is called: frmGender
my Child form is call: frmMale & frmFemale
Below is what I have tried from the example in my Child form frmMale:
Private Sub btnResults_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnResults.Click
Dim frm2 As frmMale = New frmMale()
AddHandler frm2.FormClosed, AddressOf frm2_FormClosed
[code]....
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Feb 8, 2009
I have been able to have success with Papa to Baby (parent to child), but get error message "Column GID does not belong to table" with my Baby to G (child to grandchild form), even though I have GID in my table. Here is my code?
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Aug 11, 2009
Is there any way to have a combobox inserted into a cell in a list view? Here is what I have:
[Code]...
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Oct 25, 2010
VB.NET 2003 makes it difficult to have a child button create an event on a Parent form control. I would like to change the state of a control on the parent form by using a button on the child form.
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