I am learningCreating LINQ to SQL Classes: Using the O/R Designer, the link is found below[url]...But when I Step #8 of Binding Controls on a Windows Form to Entity Classes says:8. Create an event handler for the Form_Load event by double-clicking the form. Add the following code to the event handler:
View 4 RepliesI am using the O/R Designer to create entity classes in VB 2010. I am observing different results for different database tables that I can't explain and more importantly, can't replicate the results that I want.Using server explorer, I have dragged a number of tables on the O/R designer surface, thereby creating the entity classes.
I have saved the project and can access the various entity classes in my project code. I first noticed a difference when changes made to object instances from some tables/entity classes appeared to persist while changes made to object instances from other tables/entity classes did not persist. These object instances are created, accessed, and changed using the exact same code patterns except for the object, class and table names.
I have been looking to see if there are any differences between the way in which the entity classes are treated, either in my code, in server explorer, or in the O/R Designer. I cannot find any. The properties of the entity classes indicate that all of the classes use the runtime methods for insert, delete and update. As far as I am aware, I have not knowingly made changes to these methods.
The ONLY difference that I find is in the file NameofClass.designer.vb. This is an automatically generated document. The partial class of those objects that appear to persist changes contains different code from that of other partial classes where changes to objects do not persist.In the declarations section of this partial class, the following lines appear:
<Global.System.Data.Linq.Mapping.TableAttribute(Name:="dbo.OrderofBattle")> _
Partial Public Class OrderofBattle
Implements System.ComponentModel.INotifyPropertyChanging, System.ComponentModel.INotifyPropertyChanged
[code]....
If I am right then I want to enable persistence in my other classes by causing this additional code to be generated for them. But how? why the code for this one class hase been generated differently than for all the others (actually it is this way for 2 out of about 15 classes). What setting or or selection do I have to make to enable this code to be created for my other entity classes during the automated process?
I have two classes, one nested in the other. [code]Neither "Name" or "ID" are unique between operations and records.I wish to construct a dictionary using LINQ = Dictionary(Of String, Of List(Of Integer), whereby the keys are uniqe examples of Names in my collection and the values are the collective set of distinct IDs that are associated with those names.
View 2 RepliesI have been developing some components for our products at work, and one of them is based off the flow layout panel.What i would like to do is provide a custom designer for it, but without loosing the features provided by it's default designer (System.Windows.Forms.Design.FlowLayoutPanelDesigner) which is marked as internal.Using Reflector i thought i would just implement it again myself, seeing as it inherits from 'FlowPanelDesigner and that from PanelDesigner` all of which are internal.
Why would these classes be specifically marked as internal? Is it due to them being specifically for Visual Studio use, and thus not 'framework' code?Also, is there an easier option that re-implementing all the functionality?
When attempting to create a UserControl type that must be inherited, when I try to edit one of its child classes in the Form Designer, I am not allowed to edit the child UserControl with the message:
To prevent possible data loss before loading the designer, the following errors must be resolved:
1 Error
The designer must create an instance of type "XX_ExpandContentsPanel2.IOCardMaster", but it cannot because the type is declared as abstract.
This error goes away if I remove the "MustInherit" restriction.Is there some way around this or do I just have to accept the (bonkers-mad) restriction, and not declare my class as as MustInherit, even though it's not a useful control in its own right?
If im creating a timer outside the designer how can I add things like
Dim i As Integer
i = PictureBox1.Top
Timer2.Enabled = False
[Code]....
I'm using LINQ to SQL as my data access layer for a new project.I have added my database tables to the designer and all is well.Whenever I use one of these classes in a function, Visual Studio warns me that 'Type xxxx is not CLS-compliant' or that 'Return type of function xxxx is not CLS-compliant' Is this a problem with the classes that LINQ to SQL generates? Does it matters? Can I disable these warnings anywhere? My VS error list is clogged up with these warnings making it hard to see anything else.
View 4 Replieswhat is the difference between these 2 ways to refresh a linq class
1) LinqDB.Refresh
2) LinqDB =
New DataClasses1DataContext
I have got the impression that some time the linqdb.refresh does not work at all
How to bind a textbox in design view to a LINQ to SQL datacontext class?
View 3 RepliesI am curious as to the proper technique to use SQL Server's AppRole with a LINQ to SQL Class. I understand I have to establish the intial connection with no connection pooling. However, do I simply call the SQL stored procedure sp_setapprole using standard LINQ before executing any of my methods that interact with the database, or is there a better way to enable and use AppRole within the LINQ to SQL class?
View 6 RepliesVB.net VS2008 My program dynamically populates a class as I click on specific calendar dates runtime. I am currently using various LINQ statements targeting this class for reporting purposes. However, all of my LINQ statements are hard-coded. Are there available solutions / modules which will provide me with a LINQ command and RESULTS window which can be set to an instance of a class so I can experiment with other commands runtime? Can LinqPad be used runtime against populated classes?
View 1 RepliesHow can I dynamically initiate a "new" class?Basically I'm storing references to classes in an array and I want to create and dispose them on demand.
View 4 Replies1) Add a Private variable named _area2) Associate the _area variable with a Property procedure called Area3) Change the CalculateArea method to a Sub procedure. The method should calculate the area and then assign the result to the _area variable.4) Include a parameterized constructor in the class. The constructor should accept one argument: the side measurement. After using the Public property to initialize the Private variable, the constructor should automatically call the CalculateArea method.At this point I believe I've completed the first 2 steps for the Square method, but I'm not sure where to go from therHere is my code for the Square class and the Main Form, in tha order:
Public Class Square
Private _side As Integer
Private _area As Integer
[code].....
I am trying to learn OOD/OOP and read on the net that I am not supposed convert SQL tables into classes. But I cannot find an explanation why not to do it or which tables to skip. So I made an web application based on the below diagram. It works perfectly well. But I do not use OO. which table should not be mapped into a class and why not. do not use LINQ or NHibernate, etc as I do not understand them. I just need to understand the OOD.
View 2 RepliesI'm wondering on how you would go abouts instantiating a class that contains other complex objects. for example an Payment Class which has Date,Time, etc.. and it also holds a reference to a paymethod object which has id,Type,Description etc.. How do you instantiate the payment class with all the other objects without one or the other failing, how do you create the payment class which doesn
View 4 RepliesHow would you create depth code for two classes in visual basic 2008 (like if you wanted to put one picturebox behind another picturebox depending on what each picturebox's depth equals)?[code]I can't get my movement code and the image for the character object to work.
View 3 RepliesI have a Clients master object and then a number of child objects whose exact number is not known in advance such as Client-Contacts, Client-Payments etc, all of which have a one-to-many relationship with the Client master object.How do I define classes for such a scenario? Do I for instance create the master Clients class and can then I create an array of class somehow for child objects?
View 2 RepliesI seem to be having a problem with controls that I am creating as new classes (not UserControls) inheriting from an existing system control. Everything seems ok while I create the control code, through to the compile (which is successful and adds the control to the toolbox) and dragging the control from the toolbox to the GUI surface. However, when I then debug or compile the project, I get a message such
[Code]...
I am attempting to update an existing winforms application, that was created with a dataset control on all the winforms pages. I have ported it from VS 2008 to VS 2010 and I need to update the database section and connect it to the SQL backend using traditional code method.In the Solution explorer, when I click on the Dataset files, and click "Exclude From project" I am unable to build the project.Is it advisable to comment out the code lines that refer to the dataset in the .designer.vb files?
View 1 RepliesWhile building an xml document I require to use logic to dictate the outcome of the xml; logically it is similar to the following piece of code (although this does not work):
Dim buildElement As Boolean = True
Dim xe As XElement = _
<xml>
[code]....
I have managed to do this using the method show below, is this the suggested way of doing this or is there a better one??
Dim buildElement As Boolean = True
Dim xe As XElement = _
<xml>
[code]....
why is this xml
<?xml version="1.0" encoding="utf-8"?>
<items>
<item id="77" cityID="EE12345" cityDatum="15.2.2010. 11:28:35" />
</items>
[Code]....
If you, as some can't replicate these results, here's a screenshot:
Is there any way to use a LINQ to XML to query an XML document like the one below to create new (anonymous or strongly typed) objects from the child elements of a descendant? Here is my XML document:
[Code]...
I am in the process of learning LINQ to Objects. I am querying an array of reference elements using LINQ. In the code below, which I have marked with asteriks and PROBLEM, I am having difficulty returning any values for and I suspect its because of the multiple Select arguments.
'Program name:Querying an Array of Invoice Objects
'Created/revised:
'Project description:To demonstrate the use of LINQ to query objects
[Code].....
Is there any particular reason why creating a reference to an object in an IEnumerable Linq query would be really slow? I have a Linq query list consisting of my own objects (count is about 200).I was doing a time-critical task, and this line (which was used a lot in a loop) took nearly a millisecond to execute:
Dim CurObject as MyClass = QueryResult(CurIndex)
I don't know if this is doable, maybe with Linq, but I have a List(Of MyType):
Public Class MyType
Property key As Char
Property description As String
End Class
And I want to create a Dictionary(Of Char, MyType) using the key field as the dictionary keys and the values in the List as the dictionary values, with something like:
New Dictionary(Of Char, MyType)(??)
Even if this is doable, internally it will loop through all the List items, I guess?
what account for this error message in ls beta 2?'' The last change wasn't successfully persisted.Please shot down the running application.
View 1 RepliesI can't connect to the "Service-Based Data Base" or to the "Linq To Sql classes". I tried all that I've read in the Forums for days : ( I removed the VB 2008 and SQL 2205-2208, then upload VB 2008 from my CD only. I'm starting a Web Technology class in 2 weeks, and the complition of the book is my entry requirement.
View 4 RepliesHow can I structure my classes so that the user interfaces though a single class while the supporting classes are hidden from their view? I think its best understood in an example:
Public Class MyInterface
Public Economic as EconomicClass
Public Sub New()
MyBase.New()
[code].....
So you might ask why am I even separating them? It's strictly for others who will be working with this interface. I need to funnel them though a logical structure:
interface.Economic.MyMethod
interface.Currency.MyMethod
etc
This way everything is already handled for them in the background and they only need to run the method they need. I don't know if I can have it both ways in VB.NET.
Here is some example code of what I mean:
vb
Public Class Form1
Private Sub Button1_Click(ByVal sender as Object, e as systemEventArgs) Handles Button1.Click
[Code]....
I have some question about Class I am doing all of my VB learning mostly thru this forum and via some tutorials, web searches and example programs. That being said, here I go.
From the MSDN website I came across "Creating Classes in Visual Basic"
I didn't know a Class could be created.So in your most non-technical laungage with the most layman terms posible. How would you describe a Class, Why would I need to create a Class?
[Code]...