Reflection And Changing A Variables Type At Runtime?
May 26, 2010
I'm trying to create an object Of a specific type. I've got the following code, but it fails because it can't cast the new table object to the one that is already defined. I need table to start of an IEnumerable type so I can't declare is an object.
Public sub getTable(ByVal t as Type)
Dim table As Table(Of Object)
Dim tableType As Type = GetType(Table(Of )).MakeGenericType(t)
[code]....
is there a way of changing a variable type at runtime?
Is there a way for a property to access its own name and type at runtime using reflection? I want to access this info without hard coding the name or index of the property in the class.
Simple Example Code:
Private ReadOnly Property MyProperyName() As String Get Console.WriteLine((Get Current Property Info).Type.ToString) Console.WriteLine((Get Current Property Info).Name)
I have been trying to use reflection to get at all variables I have in classes. I have a bunch of classes and they all use private fields, with public properties to access these private variables.I have used the method Type.getFields() to get to all the public fields, but it doesnt return anything. It seems to completely ignore properties. If I add some test public variables as normal, it picks these up, however I was hoping to keep using the public properties in these classes.
Is there anyway to force the Type.getFields() to pick up on public properties? I see it has some binding flags, and one for getProperty, however it doesnt seem to work.
Is it possible to get the name of a local variable from a reference to the variable? For example, I can get the names and values of a calling function's parameters like this:
Dim frame As New StackFrame(1) Dim pInfos() As ParameterInfo = frame.GetMethod().GetParameters()
Is there some way to get the same information for a calling function's local variables? This is kind of what I have in mind:
Sub SomeSub() Dim count As Integer = 10 Dim average As Single = 45.67
Is it possible to get a string form a table and executed at runtime using reflection?(.Amount > 1000) and ((.Total * 80%) >.Amount)� Amount and Total are Decimal properties of an existing class
What I wanted to do was, given the table name (as string), use reflection to instantiate the get method for specific fields (defined as properties with Get and Set methods.
I am trying to write a function that has an object parameter. That object will always be an BindingList. That BindingList will be of some unknown (at design Time) class. I think I've figured out how to get the type of the collection object, but now here the tricky part. I'm trying to create a function that can handle any type of collection and be able to return an item from that collection. I need to create a new object of that type and return it from the function. [Code]
I am trying to create an Excel file using reflection. The reason, the application will be running on many machines some of which may or not have excel installed. I decided to embed the "Microsoft.Office.Interop.Excel.dll" and via reflection generated the excel spreadsheet. The code I am trying to resemble is:
I've got a set of static "enumeration" classes that I'm using to hold meaningful variable names to represent meaningless code values I receive on an input file. Here's an example of one.
Public Class ReasonCodeValue Private Sub New() End Sub
Public Function f(ByVal t As System.Type) As Object Return t.GetConstructor(New System.Type() {}).Invoke(New Object() {}) End Function
I need to pass values to the Constructor as
Public Function f(ByVal t As System.Type) As Object Return t.GetConstructor(New System.Type() {someInteger,someString,etc.etc}).Invoke(New Object() {}) End Function
Also I have 3 classes of Type T, with all having different parametric constructor. It's important for me to have it generic as the Classes of type T might increase in future with less or more parameters.
I'm attempting to dynamically register entities and configurations with a context (ef4 code-only). I would normally do:
Private Shared Sub ConfigureDatabase(ByRef Builder As ContextBuilder(Of ContextExtension)) 'Load configurations for each of the tables (Entity sets) in our database... ConfigureEntity(Builder, New ContactConfig) End Sub Private Shared Sub ConfigureEntity(Of T)(ByRef Builder As ContextBuilder(Of ContextExtension), ByVal config As EntityConfiguration(Of T), ByVal setName As String) 'Register the entity configuration with the builder Builder.Configurations.Add(config) 'Register the entity set name with the builder Builder.RegisterSet(Of T)(setName) End Sub
Where ContactConfig is a class which inherits EntityConfiguration(Of Contact) and Contact is a class which implements an interface IEntity (IEntity is common to all entities). So... I need to search a namespace (say Project.DB.Client) for all signatures that match: EntityConfiguration(Of <Class which implements IEntity>) How can I achieve this?
I'm trying to check if a variable has been defined as a nullable Guid. eg.
Dim myGuid As Nullable(Of Guid) or Dim myGuid As Guid?
It seems doing a myGuid.GetType returns the underlying type, that is type Guid, not Guid?. So testing myGuid.GetType Is GetType(Guid?) always returns False.How do I find out if myGuid is a nullable type?
Ed: I can do the following, which correctly returns True for "Guid?" and False for "Guid":
Not Nullable.GetUnderlyingType(GetType(Guid?)) Is Nothing
The problem is that I don't know how to retrieve the nullable type from the variable itself, in order to test it. I've only been able to get the underlying (non-nullable) system type.
I've written a db helper function. I pass it an object comprised of public members, representing the row data of a table. The members are the table columns.Using reflection, I loop through these public members to create an INSERT statement for a command object and populate its parameters with the values in those members. So far so good.But now there's a table which has a uniqueidentifier column which I must not populate from the row object, as it defaults to "NEWID()" (using SQL Server 2008). Instead of skipping all Guid columns, which would be easy, I only want to skip ones defined in the row data class as "Guid" (non-nullable).Basically, I'm using the Guid? (Nullable) type to indicate it's ok to populate that uniqueidentifier column with data. If it's non-nullable, that tells me to skip it because the column has a NEWID() default value.
I'm passing a type name and some parameters from C# code into a navigation framework written in VB. The navigation framework looks for a constructor on the type that matches the parameters passed in using Type.GetConstructor(Types()). The constructor that I'm looking for expects an array of integers Integer() in vb. But it gets an array of System.Int32. I've gone so far as to try this:
[Code]...
And the VB code still sees System.Int32 on the other end, which means that it doesn't find the constructor.
I have an object that I know was originally declared was an enum, but I need tothe specificnum type. I'm aware of the GetType method and it appears to work correctly, but I can't figure out how to go from there to a direct type comparison For reference types, you can use Typeof(object1) Is Class1, but this doesn't seem to work for value types.
Im writing a app using vb.net, which has multiple front ends e.g a windows service and a windows forms app. Ive got all my business logic and database stuff compiled into 1 project (producing a dll) then the different front ends as different projects calling the dll.
In the backend / dll project Im connecting to 2 databases using app.config to store the connection strings and DataSets / TableAdapters. This all works fine .... Until
When I deploy the windows app, it deploys the exe and the dll produced by the backend project. when its installed on a client PC, Im need to point the app at a different db server and therefore need to change the connectionstring, but its packaged up in the dll.
is there any way I can use a settings file within my windows app (therefore deployed with my windows app) where I can define the connectionstring, which onload gets passsed through into my dll, so the backend connects the correct database. I know how to pass standard settings through (strings etc) but the my.settings.connectionstrings seem to be readonly.
i have a program i've made a while, and one of the users wants to be able to load his own images to the background instead of the plain grey that is there now. i've searched and searched, and basically can get this working
i just slapped that onto a button just to get it to work as i was experimenting. but that only works for a file of that name, on my computer, in that folder. what i'm looking to do is get it so a user can browse his own directories for images and upload them as the background on the form. and be able to save the settings as well. but so far i have only seen different ways to load preset images that you can load. if it's even possible? i'd assume that you'd use the openfiledialog command, but i'm not that well versed in vb as of yet.
I'm trying to change a forms title at runtime where it = my textbox's text. But I can't even get it to change to "test". When I try to google it, it comes up with vb6's .caption = "test". When I try to search it on the forum, it gives me a error message saying: "Error 502 Bad gateway"
I have a forms application and I have multiple localizations for it. I've figured out how to add a button to a form, to change the localization and then read all the labels/etc and change them to the other language.What I would want to do instead now is click a button and it changes to the other language the current form but also the entire application so that any other windows opened while the application is open open in that other language.[code]This is the code I use when a button is clicked on a form to change it to Hindi the current form. However I want to when the button is clicked, change application to continue to run on that localization instead for the remainder of the time it is open.[code]
I have a forms application and I have multiple localizations for it. I've figured out how to add a button to a form, to change the localization and then read all the labels/etc and change them to the other language.What I would want to do instead now is click a button and it changes to the other language the current form but also theentire application so that any other windows opened while the application is open open in that other language.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click If Present <> OriginalCulture Then
I am working on a project that uses a .txt file to store data for my arrays. Everything is working correctly i.e. I can read the file and write to the file, my issues when I exit out of runtime I get this msg
Quote:
M:My4BVB....Customer.txt
This file has been modified outside of the source editor. Do you want to reload it?I understand what it means, what I would like to know - is there a way to stop it from popping-up?
How do I change my code so that it will change the Value of the My.Settings.* to what TextBox1.Text is
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click If RadioButton1.Checked = True Then My.Settings.Acc1 = TextBox1.Text And My.Settings.Pass1 = TextBox2.Text
I have 2 Comboboxes on my Form which also has a DataGridView. One ComboBox is populated with Font Names and the other is populated with a range of Numbers (Font Sizes). On a button click I've added this code
