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())
[code].....
currently i am working on a project in which i am using datagridview control. if I enter key value in cell than remaining data of that particular row fetch automatically from data base. how? how to delete as row in datagridview? how to update a row in datagridview?
View 5 RepliesI have a GridView that is tied to an EntityDataSource. Most columns are normal bound columns, but two are itemtemplates. When I attempt a delete on one of the rows I receive the following message:
"A property named 'Building1.building_name' was not found on the entity during an insert, update, or delete operation. Check to ensure that properties specified as binding expressions are available to the data source."
I'm not sure how it is possible that this isn't available, since it displays the element just fine when I'm just viewing - it just throws the error when I attempt deleting a row?
I can do this without problem.
Class A
End Class
Class B : Inherit A
End Class
Dim Obj1 As A = New B
With writting a program that demotrates Binary Search Tree operation(insert, delete, and search)in VB.N NET?
View 1 RepliesMy question is How can i create insert,update,delete query by using class file and store procedure. This query is use for 3 tier.
View 2 RepliesI am new in this forum, also new in VB.Net I need to create a public class for insert and delete data to database Public Class My_DBFunctions
[Code]...
Consider:
Public MustInherit Class Column
Public ReadOnly Property ReturnSomethingUseful() As Object
Get
'return something useful
[code]....
But this gives the following error:
Public Overrides Function ParseValue(sValue As String) As Boolean'
cannot override 'Public Overridable Function ParseValue(sValue As String) As Object'
because they differ by their return types.
I accept that you can't do this, but I'd like to be able to preserve the semantics of what I'm. trying to do, which is to have an untyped version that deals with Object, but a typed version in derived classes that knows about the specific type T.
I have a Journal that records entries for different types: Journal(Of ParentT)
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I am trying to construct a generic interface class with generic functions. My goal was to use this to implement multiple worker classes for database interaction that have the same basic functionality. Each class will deal with different object for example, category, product or supplier but unless the the functions in the interface are generic that this won't work.This is the interface code that I have but I don't know if I have done it correctly. [code]
View 2 RepliesI am working on a general helper class to sort ListView SubItems. I wrote a base class that has much of the code I need. It includes a MustOverride for the Compare method so that the various inherited classes can implment their own comparisons based upon their type. For the value types, I end up with very similar code such as the following, where x and y are ListViewItems: Public Overloads Overrides Function Compare(ByVal x As Object, ByVal y As Object, ByVal sortColumnIndex As Integer, ByVal sortOrder As System.Windows.Forms.SortOrder) As Integer [code]
View 3 RepliesI need to have the following : (name1 + "a") + (name2 + "a") + ...
Dim separator() As String = {"|"}
myString.Split(separator, StringSplitOptions.None).SomeLinq(...)
I don't know what to add at the end to add an "a" to each element...
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.
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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))
[Code].....
I have a main form (Form 1) with a menu strip and navigation bar. I use the main form to launch other forms (Form 2) as children of the main form.
All of the children forms contain SQL data sets /grids. I would like (if possible) to use the save button on the main form, to save data changes of the children form to the SQL database.
I Have a Table name as sales one and another is balance i want to use insert command in sales and update for the balance table what can i do
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it showing a error as Conversion from string " UPDATE BALANCE SET OBBALANCE = " to type 'Integer' is not valid.
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.
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 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.
The code below works fine on my development PC, but when I deployed the app, it crashes.
Here is the lines of code that are relvant
Private TdsTypesList As List(Of TDS_Type)
...
TdsTypesList = (From tt In db.TDS_Types Select tt).ToList
[Code].....
I have many queries that are using linq, and none of them throw any errors. The set of data is not very large either, less that 100 rows. I dont know if I have any other queries that do not have where statements in them that work.
Running .net 3.5 without sp1 on the client machine, although I am running sp1 on my development PC. looking for a solution that doesn't require sp1 to be installed.
Edit Code breaks on the second line when remote debugging.
I looked over [URL] and tried the following, with the same error.
TdsTypesList = tl.OfType(Of TDS_Type)().ToList
I finally found a dirty workaround. Instead of pulling all of columns from that table, I was able to re-write the query to omit 1 column. This returns an object of anonymous type, and I can use that object. I still would like to know what causes this though.
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.
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Lets say i have a class Employee which cotains two propeties (Name, Year) I have another which basically contains list of Employee object i.e EmployeeList.[code]...
View 4 RepliesIs there any reason to favor one of these approaches over the other when inserting into a generic dictionary with the possibility of a key conflict? I'm building an in-memory version of a static collection so in the case of a conflict it doesn't matter whether the old or new value is used.
If Not mySettings.ContainsKey(key) Then
mySettings.Add(key, Value)
End If
[code].....
I need to have a dynamic URL preferably from a Test Classformatting this design pattern to handle dynamic links from tests. instead of a constant HomePageURL.
Namespace TestDesign
Public Class HomePage
Inherits IE
[code].....
How can I recognize (.NET 2) a generic class?
Class A(Of T)
End Class
' not work '
If TypeOf myObject Is A Then
I have the following sample code in a VB.NET console application. It compiles and works, but feels like a hack. Is there a way to define EmptyChild so that it inherits from Intermediate(Of T As Class) without using the dummy EmptyClass?
Module Module1
Sub Main()
Dim Child1 = New RealChild()[code].....
The other way to do this would be to move the generic code out of the Base class and then create 2 Intermediate classes like this [code]...
Then RealChild would inherit from the generic Intermediate and EmptyChild would inherit from the non-generic Intermediate. My problem with that solution is that the Base class is in a separate assembly and I need to keep the code that handles the generic type in that assembly. And there is functionality in the Intermediate class that does not belong in the assembly with the Base class.
I created two classes. One class is StudentClass and the other is HomeroomClass. The HomeroomClass contains a readonly property as a generic list of the StudentClass. [code]...
View 6 RepliesI am really trying to follow the DRY principle. I have a sub that looks like this?
Private Sub DoSupplyModel
OutputLine("ITEM SUMMARIES")
Dim ItemSumms As New SupplyModel.ItemSummaries(_currentSupplyModel, _excelRows)
ItemSumms.FillRows()
[Code]...