I made a library in C# and I've been told by people that one of mine methods don't work in VB.NET as extension [UR]
this is the method:
public static PropertyDescriptorCollection GetProps(this object o)
{
return GetProps(o.GetType());
}
I know what extension methods are, how to create and use them, but I wanted to know more about how they actually work. How do they "attach" themselves to the type of object that you are extending? Or is there even an attachment being made. I know want to know more about the inner workings, etc.. I looked around and read several different blog posts about extensions and not one of them discusses how they actually work.
View 6 RepliesIs it really impossible to create an extension method in C# where the instance is passed as a reference?
Heres a sample VB.NET console app:
Imports System.Runtime.CompilerServices
Module Module1
[code].....
I wanna create extension method for IEnumerable(Of FileSystemInfo). However, compiler says "'Sort' is not a member of'System.Collections. Generic. IEnumerable(Of System.IO.FileSystemInfo)". What is strange is that IntelliSense shows this method. Where's error? [code]
View 1 RepliesI have the following extension method. However, when I type "File." this method doesn't pop-up. What did I wrong?
[Code]...
I want to extend the BitConverter class with an overload of ToString() that takes a parameter of type Char, representing a value delimiter.Why? By default, the ToString() call returns a string representation of a byte array, delimited by dash symbols. The signature does not allow you to specify a different delimiter, which I find very unfortunate.Now because this is not an instance type, or maybe because I'm overloading a shared method, I'm having a hard time finding the proper syntax to define my extension method.What am I doing wrong here, causing the overloads to not show up in IntelliSense:
Imports System.Runtime.CompilerServices
Module BitConverterExtensions
<Extension()>
[code].....
I'm trying to use PGK.Extensions in a T4 template in VS2008 for VB.NET and I get:
RemoveAllSpecialCharacters is not a member of string..
My T4 headers:
<#@ template language="VB" hostspecific="false" debug="true" inherits="Microsoft.VisualStudio.TextTemplating.VSHost.ModelingTextTransformation" #>
<#@ output extension="vb" #>
<#@ assembly name="PGK.Extensions.dll" #> // the dll is found
<#@ import namespace="StringExtensions" #> //Try with and without namespace
[Code]...
I would like to know your opinion on extension methods. Sure, it is a nice feature and makes you feel powerful. It's great to see your own method pop up when typing in a object. But it doesn't really add something new... You can get the job done with normal methods as well. I think extension methods do not belong in object oriented programming. It makes your code easier to read but harder to understand for someone else.
View 2 RepliesCODE:
View 2 RepliesI'm trying to write 2 extension methods to handle Enum types.One to use the description attribute to give some better explanation to the enum options and a second method to list the enum options and their description to use in a selectlist or some kind of collection.You can read my code up to now here:
<Extension()> _
Public Function ToDescriptionString(ByVal en As System.Enum) As String
Dim type As Type = en.GetType
Dim entries() As String = en.ToString().Split(","c)
[code]....
So my problem is both extension methods don't work that well together. The methods that converts the enum options to an ienumerable can't use the extension method to get the description.
I wonder why it's impossible to create and extension method for Object? I use Excel PIA. The property Cells of Worksheet returns Object (if using with indexes). For example, Worksheet.Cells(1, 1) returns Object type. I know it's a Range object, and I want to cast it to Range. It would be convenient to write following:[code]
View 5 RepliesIn an other post of mine, a discussion was going on to change the extensions of mdb so user does not recognize it as Access DB (this is important for me) I tried this and changed extension to xrd, ran the application and it gave error. Off course it could not find my mdb. How to handle this? Do I need to make all the connections again?
View 5 RepliesIf I try to call my extension method which is defined like this:
Module LinqExtensions
<System.Runtime.CompilerServices.Extension()> _
Public Function ToSortableBindingList(Of TSource)(ByVal source As IEnumerable(Of TSource))
[code].....
Code in VB.NET
[Code]...
works very well. So seems some consistency miss of the string constant behavior.
2) Have a look on the COMMENTS (in the attached picture). The words "custom", "string" and "error" are highlighted, however they are in the comments, so should be green, not blue.
Why this? What workaround? EDIT: Declared as "bug" in Microsoft Connect (even if is not more that a syntactic "miss")... EDIT 2: As remarked Hans Passant, standard string methods, like "cucu".Trim() does not work either.
Consider the following:
Public Module Extensions
<Extension()> _
Public Sub Initialize(ByRef Target as SomeClass, ByVal SomeParam as Something )
[code].....
Why is Case 1 failing to initialize the object as expected?
In VB.NET or C#, is there a way to determine if a class has been extended with extension methods?
View 3 RepliesIs there anyway to add an overload "extension method" to a method that already has one or more extension methods?For example theString.Contains method has two extension methods totalling 3 separate versions.Is there anyway to add an extra extension method also called "Contains" ?By the way I have tried it but the IDE does not seem to recognise additional EXTENSION methods where a method already hasone or more extension methods.Is there anyway around this restriction?In other words I would like to be able to change the Extension method below from"Contain" to "Contains" but it seems it is not recognised.
Option Strict On
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
[code].....
I wrote some string extension methods in a VB assembly and am unit testing them from a C# project. However, C# acts like it cannot see the the extension methods, when other VB projects reference the VB assembly they have no problem. Both the VB assemebly and the C# test project are targeting .Net 3.5. Is there a way around this?
[Code]...
I have many similar calls to database and they work fine
Using ta As New QT_SSTEntities
Return ta.Product.
Select(Function(c) New RadComboBoxData() With {.Text = c.FieldName1, .Value = c.FieldName1}).
[Code].....
This error is exceptionally annoying.I've done various searches, and have been able to fix this issue.I am one of several developers on the application and the only one with the issue. I've fixed it before temporarily by adding an extension to the My Extensions panel in the project's properties (which generates a different error) and then removing that new extension.That made the error go away.
If Not My.Computer.Network.IsAvailable Then
ISConnectedToNetwork = False[code]....
Gives the error:'Computer' is not a member of 'My'.
I'm using extension methods based on an array and I would like to know if there is an easy way to check that array got a specify size instead of me doing a copy paste of
if array.count != 1000
throw new exception "size of the array does not match"
in about ~50 extensions
this a small sample of extensions that I use, I got WAY more
<Extension()>
Public Function IsWhite(ByVal board() As bitPiece, ByVal pos As Integer) As Boolean
Return (board(pos) And bitPiece.White) = bitPiece.White
End Function
[code]....
I have the code as below:
Dim xdTest As XDocument = XDocument.Load(GetXMLPath())
Dim objResult = From xe In xdTest.Elements("Some Element") _
Where xe.Element("strName").Value = strInput _
Select xe.Element("intValue").Value
objResult.
I cannot access any extension methods for objResult, like .ToList() or .First(). The file imports System.Linq and the project is targeted to .NET 3.5. How do I get the extension methods back?
I have a project written in MVC2 and VB.NET. I use a lot of htmlhelper extension methods,and I have them all in a public module. They work just fine, and I can compile and run my project. I reference the namespace they are in with this:<%@ Import Namespace="MyProject.WebUI.Extensions" %>So, again, they work great, my project runs and compiles without a hitch.The problem is that each one of these extension methods is shown as an error:
Error 33 'TabbedMenu' is not a member of 'System.Web.Mvc.HtmlHelper(Of Object)'. C:ProjectsMyProjectMyProject.WebUIViewsSharedSite.Master 23 21 MyProject.WebUI
[code]....
I have a number of very useful extension methods that I'd like to use in my Silverlight project.I've pasted the Module here [URL]The problem I'm having is that visual studio complains that the dlls my module have been written against have not been built against the Silverlight runtime.Is there an easy way to get these extension methods working in Silverlight?I'm thinking my main hurdle is getting IObjectSet and ObjectContext to run against the Silverlight run-time - perhaps there's another way to expose these methods that I'm not aware of.
View 1 RepliesI am trying to change the background color of a tooltip
I am using tooltip.backgroundcolor = color.colr
No errors but thecolor doesn't change
I have an application that requires data be entered, and after entering, a button is clicked to process that data. Clicking the button works just as it should--the data is processed properly. In constructing a test module, I provide a set of data values, followed by:
btnWhatever.PerformClick()
Nothing happens. I have used this syntax for years, and it has always worked flawlessly. I have triple checked everything else and isolated the problem to the failure of the PerformClick(). The PerformClick() is in a test subroutine that does nothing but fill textboxes and labels with default data, then calls the PerformClick() on the button to begin processing. Again, the button works fine, the data is entered as it should be, but the PerformClick() does not fire the click event.
Possible Duplicate: Datagridview doesnt work! I have written code to show records in a datagridview but it shows nothing. I have tried to debug & when it step into GetData function following codes
Catch ex As Exception
returnData = Nothing
If connection.State = ConnectionState.Open Then
connection.Close()
End If
become gray & it shows error sign. When I take my mouse pointer on it it shows message. It says "Cannot open database SUIMT requested by the login. The login failed. Login failed for user 'MY-PCJames'".
Imports System.Data.SqlClient
Public Class Form34
Private Const ConnectionString As String = "Server=.SQLEXPRESS;" & _
"Database=SUIMT;Trusted_Connection=True"
[code]....
So I have 2 data files, single dimension, that I'm trying to populate two rtb. If I comment one streamreader out the other will print. This also works in the vise versa situation. Does anybody see where I'm going wrong with this? They won't run together.
Dim Alpha As New System.IO.StreamReader("alpha.dat")
Dim Beta As New System.IO.StreamReader("beta.dat")
Dim strLine As String
[code].....
dim str as nullable(of string) is this syntax incorrect?
View 1 Repliesi'm working on a MDI application and need to view a ".PDF" files in a MDI child form, but when using the AxAcroPDF control it doesent work, note that it works fine when viewing the form separately from the MDI application.
View 14 Replies