I need to this at runtime. I checked using Reflector and value types line like Int16, for example, should contain
[Code]...
EDIT: only for the example I used directly GetType(UInt16) but in real code this part is substituted by an instance of unknown-at-design-time .NET Type
I accidently wrote some code today that was like this[code]...
I immediately noticed the issue, but I had already hit the run button. It compiled successfully, I ran it through to the section and it threw an exception.
You can't do this in C#, it gives a compile error "cannot convert from 'int?' to 'int'".
Is there an 'Option Explicit' type switch that I can turn on to ensure that this sort of error does not occur again?
If i have a computer that runs so fast such that it could make over 9e18 ticks per hour, when stopwatch.elapsedticks reached its maximum, does it resets itself or stays at Long.MaxValue?
View 6 RepliesWhen setting a DataSet row column to Nothing, like row.Date = Nothing, why does it initialize it to the data type minvalue? In this case a date, that gets set to 0000-01-01. The column is set to allow null etc., and if I don't set the row to anything at all, it will leave the column empty. So why does Nothing act this way?
In C# I would've set it to DbNull, I guess, but I'm a tad green on VB.NET - as you might be able to tell. :)
If a AJAX-Enabled WCF should return an Object with a Date Property which is Nothing a Request to this Service fails.[code]Chrome displays on this call the following error message: "failed to load resource".Has anyone an explanation/idea for this behaviour and how are you supposed to prevent this problem?
View 1 RepliesI have created a custom ValueType:
Private Structure MyValueType
Private _integerValue As Integer
Public Sub New(initValue As Integer)
[code]....
But I can't work out how I can test the value such as this:
Dim v As New MyValueType(3)
Dim x As New MyValueType(4)
[code]....
Error:Operator '=' is not defined for Types MyValueType and MyValueType
So how do I define Operators for my ValueType (I know this must be simple but I can't find an exmaple anywhere!)?Note I don't want to test If v.Equals(x)
I've just spotted this thread:>> [URL] Here is a C# article on the subject:>> [URL] how to constrain to a ValueType?
I,E:
Public Class ExampleClass(Of T As System.ValueType)
End Class
Am I correct in believing that any object that doesn't inherit from System.ValueType must therefore by definition be a reference type?
View 4 RepliesI attempting to implement the Addemar Web Service (e-marketing system) into my VB.NET application. I've managed to get a connection and called a simple method, returning a array of field id's that is. I get into truble when I want to return the label of that particular id.Value of type '1-dimensional array of WindowsApplication1.AddemarWS.NamedValue' cannot be converted to 'WindowsApplication1.AddemarWS.NamedValue'.
[Code]....
fast way in VB to go from a string to a generic type T constrained to a valuetype (Of T as Structure), when I know that T will always be some number type?This is too slow for my taste:
Return DirectCast(Convert.ChangeType(myStr, GetType(T)), T)
But it seems to be the only sane method of getting from a String --> T. I've tried using Reflector to see how Convert.ChangeType works, and while I can convert from the String to a given number type via a hacked-up version of that code, I have no idea how to jam that type back into T so it can be returned.
I'll add that part of the speed penalty I'm seeing (in a timing loop) is because the return value is getting assigned to a Nullable(Of T) value. If I strongly-type my class for a specific number type (i.e., UInt16), then I can vastly increase the performance, but then the class would need to be duplicated for each numeric type that I use.
It'd almost be nice if there was converter to/from T while working on it in a generic method/class. Maybe there is and I'm oblivious to its existence?
Conclusion:Testing the three provided implementations below and my original DirectCast/ChangeType form, @peenut's approach of using a prepared delegate to fetch the Parse method from a basic type works. No error checking is done, however, so implementors need to remember to only use this with valuetypes that have a Parse method available. Or extend the below to do error checking.
All runs were done on a 32bit system running Windows Server 2003 R2 with 4GB of RAM. Each "run" is 1,000,000 executions (ops) of the method to be tested, timed with StopWatch and reported back in milliseconds.
Original DirectCast(Convert.ChangeType(myStr, GetType(T)), T):
1000000 ops: 597ms
Average of 1000000 ops over 10 runs: 472ms
Average of 1000000 ops over 10 runs: 458ms
[code]....
Comparatively, peenut's approach is almost 200ms faster when executed 1,000,000 times in a tight loop, so his approach wins out.
what's the main difference between a Class and a Type and a ValueType.and is a Delegate a Type? or an eventhandler/event (the actual event itself)is every object a type? or is it only true in VB
View 3 RepliesDoes anyone know of a fast way in VB to go from a string to a generic type T constrained to a valuetype (Of T as Structure), when I know that T will always be some number type?This is too slow for my taste:
Return DirectCast(Convert.ChangeType(myStr, GetType(T)), T)
But it seems to be the only sane method of getting from a String --> T. I've tried using Reflector to see how Convert.ChangeType works, and while I can convert from the String to a given number type via a hacked-up version of that code, I have no idea how to jam that type back into T so it can be returned.
I'll add that part of the speed penalty I'm seeing (in a timing loop) is because the return value is getting assigned to a Nullable(Of T) value. If I strongly-type my class for a specific number type (i.e., UInt16), then I can vastly increase the performance, but then the class would need to be duplicated for each numeric type that I use.
It'd almost be nice if there was converter to/from T while working on it in a generic method/class. Maybe there is and I'm oblivious to its existence?
Conclusion:Testing the three provided implementations below and my original DirectCast/ChangeType form, @peenut's approach of using a prepared delegate to fetch the Parse method from a basic type works. No error checking is done, however, so implementors need to remember to only use this with valuetypes that have a Parse method available. Or extend the below to do error checking.
All runs were done on a 32bit system running Windows Server 2003 R2 with 4GB of RAM. Each "run" is 1,000,000 executions (ops) of the method to be tested, timed with StopWatch and reported back in milliseconds.
Original DirectCast(Convert.ChangeType(myStr, GetType(T)), T):
1000000 ops: 597ms
Average of 1000000 ops over 10 runs: 472ms
Average of 1000000 ops over 10 runs: 458ms
[code]....
Using System.Reflection and calling InvokeMethod to get at the Parse method:
1000000 ops: 12213ms
Average of 1000000 ops over 10 runs: 11468ms
Average of 1000000 ops over 10 runs: 11509ms
Average of 1000000 ops over 10 runs: 11524ms
[code]....
Konrad's approach to generate IL code to access the Parse method and store the call into a delegate:
1000000 ops: 352ms
Average of 1000000 ops over 10 runs: 316ms
Average of 1000000 ops over 10 runs: 315ms
[code]....
peenut's approach of using a delegate to access the Parse method directly:
1000000 ops: 272ms
Average of 1000000 ops over 10 runs: 272ms
Average of 1000000 ops over 10 runs: 275ms
[code]....
Comparatively, peenut's approach is almost 200ms faster when executed 1,000,000 times in a tight loop, so his approach wins out. Although, Konrad's wasn't far behind and is itself a fascinating study of things like ILGenerator.
I'm wondering if there's a way to use Reflection to inspect properties of a COM object? GetType() doesn't want to return the actual type.
View 3 RepliesI 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.
[Code]...
I am trying to build a test app to test my objects. I want it to get all the classes/modules from a project/exe/dll then display the methods and allow them to be invoked. I can get a list from the running project, a dll or exe. But I am having trouble filtering.
[Code]...
I have inherited a large project written in a mixture of C# and VB.Net
The project involves many separate assemblies.
There are hundreds (or thousands) of resources (png files) that have been inserted into the project using the VB My.Resources functionality that I would like to access from some C# code, in a different assembly.
Microsoft has a KB article about this. It includes some sample code, but I can't get it to work (and I can't quite follow the code).
// Gets a reference to the same assembly that
// contains the type that is creating the ResourceManager.
System.Reflection.Assembly myAssembly;
[Code]......
.net - Using reflection in C# to try and access My.Resources
View 2 RepliesI am using System.Reflection to load a type that I cannot otherwise load during design time. I need to pull all controls within a collection of this type, however, i the OfType command doesn't seem to like the reflection Syntax. here is "close to" what I got.
Dim ControlType As Type = System.Reflection.Assembly.GetAssembly( _
GetType(MyAssembly.MyControl)) _
.GetType("MyAssembly.MyUnexposedControl")
Dim Matches as List(Of Control) = MyBaseControl.Controls.OfType(Of ControlType)
So that code is bogus, it doesn't work, but you get the idea of what I am trying to do. So is there a way to use reflection and get all of the controls that are of that type?
I know how to get the properties using reflection but how would you get the function name and type of a property:
For Example: Combobox.Items.Add
I would like to get the info. for "Add" with reflection. Is this possible in .Net?
I would like to perform an audit as part of a unit test that uses reflection to verify some assumptions, the basic-psuedo code for this would be as follows:
[Code]...
I'm working on a new DAL for my latest project. As the performance is essential I'm avoiding late binding/reflection as much as possible. One central part is the DAL function for populating Business Objects.One class is called in order to connect to the database with the given SQL (stored procedures can't be used in this environment) and the given Business Object or List is populated. As different Business Object types will be populated by the same function I made an Interface that all of the Business Objects implements with the Sub called "Fill". The question is - will reflection be used in this scenario? My thought was as I'm "describing" the objects trought the interface the compiler doesn't need to use Reflection.
[Code]...
I can't work out how to get the parameter types for an event.For instance, I can only see using a MethodInfo to get parameters, but I have either an EventInfo or a FieldInfo.What I want is to be able to get 'Boolean' from this:Public Event EventName(ByVal sender As Object, ByVal value As Boolean)I could theoretically try something like GetRaiseMethod() but that won't work (because that method returns null as per this link) and even if it did it would require a method binding first and this is meant to be for a test suite just confirming that the event has a certain typed parameter at initialisation.
View 1 RepliesHow to get property.value from reflection.assembly?
Dim assembly As Assembly = assembly.GetExecutingAssembly()
For Each assemblyType As Type In assembly.GetTypes()
If assemblyType.IsSubclassOf(GetType(Form)) Then
[Code].....
I would like to list all visible controls in a form, I use reflection to do this, I have done what I want, but I have to write code for specifics controls that doesnt exist in the Framework, so i would like to know if there is some code to do that generic for any control (even third party controls).
Private Sub LlenarArbolFormularios(ByVal Arbol As TreeList)
Dim parentForRootNodes As TreeListNode = Nothing
Dim tipos() As Type = System.Reflection.Assembly.GetExecutingAssembly().GetTypes()[code]......
I would like to load a class library at runtime. As such, I thought I could use reflection to do so.However I am receiving the exception "Unable to cast object of type 'MyLibrary.LogSystem' to type 'MainApp.ILog'." in my main application. To start with I created a Class Library (VS2010) with a simple interface and one class that implements the interface.
[Code]...
Im using system.reflection to inject a managed (.net) file directly into memory.This injection works with other managed files, but this file has data in the EOF and it wont run without that data.
View 1 RepliesI'm trying to use reflection to get the instance of a class in vb.net. I have a class 'A' in my web project and to test it, i create a new aspx page and try to write the following:
Dim t as Type = Type.GetType("A")
This returns "Nothing". But if i do this:
Dim inst as A = new A()
Dim t as Type = inst.GetType()
t's type is "A"
So how come i can't get the type with GetType even if the name is exactly the same? It does works for things like System.Math though
I'm trying to use reflection to populate the properties of an array of a child property... not sure that's clear, so it's probably best explained in code:
Parent Class:
Public Class parent
Private _child As childObject()
Public Property child As childObject()
Get
Return _child
[Code] .....
The issue is now trying to get that array assigned to the parent object (using reflection). It shouldn't be difficult, but I think the problem comes because I don't necessarily know the parent/child types. I'm using reflection to determine which parent/child is being passed in. The parent always has only one property, which is an array of the child object. When I try assigning the child array to the parent object, I get a invalid cast exception saying it can't convert Object[] to.
Basically, what I have now is:
Dim PropChildInfo As PropertyInfo() = ResponseObject.GetType().GetProperties()
For Each PropItem As PropertyInfo In PropChildInfo
PropItem.SetValue(ResponseObject, ResponseChildren, Nothing)
Next
ResponseObject is an instance of the parent Class, and ResponseChildren is an array of the childObject Class.
This fails with:
Object of type 'System.Object[]' cannot be converted to type 'childObject[]'.
In Visual Basic I have A form Called Your Details Form and after filling out textbox1,[code]But how can I have the Reflection label read from textbox1, and put the textbox1 text into the Reflection label to get the results as per picture Below. then have the Reflection Label across all forms.
View 12 RepliesIs 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
[Code]......
