I am trying to develop a simple interface for allowing quick lists to be generated from classes. Basically, the interface needs to return an ID and a Name. However, some classes have a calculated name property which is read only, others just use a read/write name property. Basically, all I care is that it has a getter, it does not matter if the property has a setter. How can I write this interface to handle either or without throwing compile errors?
Is there a way for implementers of an interface where a ReadOnly property is defined to make it a complete Read/Write Property ?
Imagine I define an interface to provide a ReadOnly Property (i.e., just a getter for a given value) :
Interface SomeInterface 'the interface only say that implementers must provide a value for reading ReadOnly Property PublicProperty As String End Interface
This means implementers must commit to providing a value. But I would like a given implementer to also allow setting that value. In my head, this would mean providing the Property's setter as part of the implementation, doing something like this :
Public Property PublicProperty As String Implements SomeInterface.PublicProperty Get Return _myProperty
I have the following Imports System Imports System.Collections.Generic Imports System.Drawing Imports System.Linq Imports System.Windows.Forms [Code] .....
But I am getting this error: Error1Class 'DemoPlugInTwo' must implement 'ReadOnly Property name() As String' for interface 'Interfaces.IPlugins'. Implementing property must have matching 'ReadOnly' or 'WriteOnly' specifiers.C:Documents and SettingsOwnerMy DocumentsVisual Studio 2008ProjectsDemoPlugInThreeDemoPlugInThreeDemoPlugInThree.vb1420DemoPlugInThree I am getting similar errors for the other property and method. I have them set as read only.
I am using a PropertyGrid control to edit my class properties and I am trying to set certain properties read-only depending on other property settings.This is the code of my class:
Imports System.ComponentModel Imports System.Reflection Public Class PropertyClass[code].....
This is the code I am using to edit the values:
Dim c As New PropertyClass PropertyGrid1.SelectedObject = c
The problem is that when I set SomeProperty to True, nothing happens and when I then set it to False again it sets all properties Read-Only.
I have come across something confusing or potentially a bug in Visual Studio 2010 when defining an interface in my VB application: When defining an interface method with a default parameter of type Double, using the Double.NaN constant as the default value causes the code editor/intellisense/precompiler some issues.The following code underlines "INaNTest" and "INaNTest.DoSomething" claiming that 'DoSomething' cannot implement 'DoSomething' because there is no matching sub on interface 'INaNTest':
[code]...
where now "NaN" has been divorced from the "Double." prefix and underlined ('NaN' is not declared. It may be inaccessible due to its protection level.) The code editor has inserted invalid code again.Is there a correct solution to using Double.NaN as the default value for a method as defined on an interface, in VB.net, or is there a fundamental reason why this is impossible?
I am retrieving several properties of a control. Here is how I used to retrieve properties (with pinfo of type PropertyInfo):
value = pinfo.GetValue(obj, nothing)
That worked well, but now I am facing a property that has a optional value, and I get an error message telling me that the number of parameters is incorrect. So I changed my code by this one:
Dim index As Object() = {Nothing} value = pinfo.GetValue(obj, index)
At this point, I didn't get any error message, but this code doesn't retrieve the good value. It only works if I replace Nothing by the default value provided by the property accessor...
But I don't know in advance what this default value is! And this code is within a function that retrieves properties that doesn't have optional values, so I cannot change the code especially for one case or another..
I am working on .NET 2.0
EDIT: More precisions about the case leading to the problem
Here is an example of property leading to the problem:
ReadOnly Property Foo(Optional ByVal Number As Integer = -1) As String Get If Number = -1 Then
[Code]....
With this kind of property, none of the codes above retrieve the good string.
My best guess would be to try the first code for general purposes, catch the appropriate exception, and then dynamically retrieve the default value of the parameter (Number in that case) and its type, so that I can call getValue with this default value.
So, How can I retrieve the default value of the optional parameter?
am trying to add an extra optional parameter to a property but it gives this message.Specifiers valid only at the beginning of a declaration. Public ReadOnly Property ReadValue(ByVal Selection As String, ByVal Key As String,Optional Default as string="") As String
I have a user control and I'd like to give it a custom property named ReadOnly. I get "Keyword is not valid as an identifier", as it thinks I'm writing a ReadOnly Property named something.
so really I can call mine 'Read_Only', but I'm just curious if there's an easy way to get the other name in there, since then my control will be similar to the visual controls that have ReadOnly in the designer.
It seems that VB.NET and C# readonly keyword have some differences... Say, a ReadOnly property in C# can be assigned in some conditions, but in VB.NET - never?
THis is a line of code i have, it's a code to go at the bottom of a document and the title of the question is the error it has, how do i change the 'Chars' to not be read only? I can only guess 'Chars' is a character.
pagecode(1) ="01274-6759q-DDD"
If you're not living on the edge, you're taking up too much room
i have this code to build datagridview column. I will fill this coulmn with the data from another column (I have done it) But now, I want it so that the table property READONLY: TRUE and the column TOTAL_PRICE to have $#.00 format.
Public Class columnLoader Public Sub New(ByVal system As String, ByVal quantity As Integer, ByVal description As String, ByVal totalPrice As Double)
I am using a Micrsoft Web Browser Control (i.e. the AxWebBrowser NOT the standard web browser). The only way I can declare the variable for it is as follows:
Dim wb1 As New AxSHDocVw.AxWebBrowser However I cannot then do the following: wb1.Name "WebBr1" It says the Property Name is ReadOnly
It seems that in the following example, TestProperty() and TestDouble() are functionally equivalent. Is the case? I usually use Property/Get when I have a single line "Return Variable_" type of "function", and Function when I have a more involved thing going on. Is that reasonable?
vb Public Class TestClass Public ReadOnly Property TestProperty() As Double
how can i solve this error in my code i have access database and i need to connect to it and that was done but when i was trying to add new record it gives me the below error Error 1 Property 'Item' is 'ReadOnly'.
In my class there's an object belonging to Process class. So, in my wrapper class, I need to get the "StartTime" & "EndTime" of the process object. I'm having confusion whether to use a ReadOnly property for this or a function returning the date, in my wrapper class
Is it a good practice to use a function for this purpose or a property ?
I'm faced with a couple of problems in VB.net: I have a series of objects, which properties I'm displaying in a grid for the user to edit. My first problem is: how do I get a list of all the properties of an object? Is it even possible? The datagrid control that I'm using accepts string values with the name of the property as parameters, but inserting them manually would be a real problem, because there are a LOT of them. So: is there a way to get a list of strings with the name of each property of an object?
If that's possible, here comes the second question: Now, of course, since users are editing the properties, I'm not interested in showing ReadOnly properties which they cannot edit. Hence my secodn problem: is there a way to check if a property is readonly at runtime?
I have a Windows Form that contains a DataGridView. The DataGridView ReadOnly property is set to TRUE. The DataGridView as 3 columns. I would like to make the cells edible (ReadOnly=False) when the RowHeader is clicked. I thought that the following code would do it, but when I click on a RowHeader and then click in one of the cells in that row, the cell is still ReadOnly.
Private Sub dgvData_RowHeaderMouseClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellMouseEventArgs) Handles dgvData.RowHeaderMouseClick
The error message Implementing property must have matching 'ReadOnly' or 'WriteOnly' specifiers is pretty self-explanatory, so I do know what's wrong here. It's also not a big issue, because it's quite easy to work around this limitiation. I'm curious, though: Does anyone know why the VB designers decided to treat this case differently than in C#?
I am trying to create the functionality of resetting the password for the program. However, when I try to create the code for this feature, I am getting "Property 'Password' is 'ReadOnly'". How would I go about getting around this.
Dim strUsername As String = txtNewUsername.Text Dim strNewPassword As String = txtNewPassword.Text Dim strOldPassword As String = txtOldPassword.Text txtNewUsername.Text = strUsername txtNewPassword.Text = strNewPassword txtOldPassword.Text = strOldPassword [Code] .....
