C# - Creating A Generic IList Instance Using Reflection?

Feb 4 10 at 10:45

I am trying to create a generic list of objects using reflection. The below code throws an error Cannot create an instance of an interface. . I could change the IList to List and it works fine, but I was wondering if there is way to get this working with an IList.

var name = typeof (IList<T>).AssemblyQualifiedName;
Type type = Type.GetType(name);
var list = Activator.CreateInstance(type);


Forms Data Controls :: Casting From Generic IList To Object During DataBind?

Feb 18, 2010 12:48 PM

Okay, so I have a Generic IList of custom objects that I want to use as a datasource for a repeater.


In the WebForm inside the repeater, I place this code:


when I try to run it, I get the error "Unable to cast object of type 'System.Collections.Generic.List`1[MyCustomObject]' to type'MyCustomObject'. ". Which makes sense, really.

What's the best way round this? Is there any way I can get the direct cast working? I'm loath to have to create a custom list item that implements IBinding or something and bind that directly, as that'll mean a lot of legacy changes which may create further bugs. Or is there a better way?

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.net - Generic Way Of Checking Property Type Using Reflection

Mar 25 at 15:07

I am trying to set property value using reflection as below. I wanted to know if there is any generic way of finding the property type instead of doing it int he below way.

string currentlblTxt;
string currentTxt;
Assembly assembly = Assembly.GetAssembly(typeof(myAdapter));
myAdapter currentEventObject = (myAdapter)assembly.CreateInstance(myClassName);

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C# - Trying To Create Instance Of Class By Using Reflection

Apr 16 10 at 22:19

I am trying to create instance of class by using reflection in ASP.net web site. Class ClassName is defined and located in App_code folder. Following line returns null, what could be wrong.

Type type = Type.GetType("NameSpace.ClassName", false, true);

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C# - Create An Instance Of A Web Control Using Reflection?

Oct 20 10 at 20:59

How can I create an instance of a web control at runtime using reflection? I created a series of controls that implement a common interface and I would like to create these controls based on the name of the control which is stored in my database.

I have attempted (and failed) to create an instance of these controls using Activator.CreateInstance in the following ways:




...and both return null.

I've also attempted to simply get the type of the control by trying..

Type t = Type.GetType("controls_myusercontrol_ascx");


Type t = Type.GetType("MyUserControl");

...and it returns null.

If I explicitly declare an object as controls_myusercontrol_ascx or MyUserControl, there is no issue -- but it can't be found with reflection.

Is it possible to create web user controls using reflection at run time? If so, how can I?

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C# - Create A New Instance Of A Type Without Reflection?

Jan 14 at 2:02

I have a function that at the moment takes a Type variable. This function sticks it in a list and such and eventually needs will create a class of that type. Right now I do that with

object o=MyType.GetConstructors()[0].Invoke(new object[0]);

which is pretty hacky and also will not work in medium trust due to reflection(I think). Is there a better way of doing this without reflection? The Type is defined this way as part of a function. I need the class to be created "lazily" because it may not be created in the application if it's not needed. I use it for example like


Note, I'm open to suggestions on changing the function calling. I just need the object to be created lazily and for to store the type(or however to create an object of the type) in a list.

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ADO.NET :: Creating A Generic Function - Data Access Layer

Feb 01, 2011 04:04 AM

I have written the following functions(1 & 2) in a class file(say abc.vb) to execute a sql statement in code behind.


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C# - Creating A Generic Data Editing User Control?

Feb 11 10 at 0:44

I have a user control which has a Gridview and a listview, I want to make this control generic so that I can just pass the type of the class I want to edit, which would be a linq entity, and then it would automatically do the rest, so far I havent had any success and I was wondering if anybody knows a tutorial or some info about doing this?

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MVC :: Creating A Generic Template Writer That Can Handle Drop Downs And Option Lists?

Sep 20, 2010 07:50 PM

If I have a the following model


And the following generic control template writer (which would have to be extended appropriately)


I would like to be able to add an attribute either builtin or something I create, such as


The generic template writer would then automatically create a Select box instead of a textbox for this item, and populate it with the list I have passed.

There may need to be another property set to have it write option boxes or radio buttons.

The question has two parts: (1) Is this an appropriate metaphor? and (2) Can you point me to an example that does this or to an appropriate metaphor.

What I want is a generic control writer that looks at the type of the object, writes the appropriate html, and a way to pass in external data for things like lists and enums.

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Web Forms :: Creating Instance Of Webpage

Jul 08, 2010 06:28 AM

i've got a project requirement in which a webpage developed in asp.net+C# - (used for information gathering from the end user) can be changed to a report view of the same page (after submitting) with dynamic html formatting without affecting the original page can it be done by creating an object of that webpage and modifying its properties or creating an instance of the page or something like that.

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MVC :: Creating An Instance Of A Repository Class

Jul 23, 2009 08:25 PM

I have a repository class where i do my stuff with the database. All things works just fine in the Home/Index and Home/About Controllers. I can get the lists that i want, but when i create a new Controller (PlayerController) i get this error when i try to use the repository instance.

"System.InvalidOperationException: The model item passed into the dictionary is of type 'System.Collections.Generic.List`1[ManagerApp.Models.Player]' but this dictionary requires a model item of type 'ManagerApp.Models.Player'." Here is the Controller code:


And my PlayerRepository class:


As said before. Im using the exact same code in my Home/Index controller and it works just fine. What is wrong?

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Web Forms :: Creating Instance Of COM Component With CLSID

Jul 30, 2008 07:17 AM

i have an asp.net website that is working (from filtering data from a database up to exporting of filtered data into an excel file) well in my local IIS. after transferring the website into a server, the filtering of data from database is working but when i try to export the filtered data into an excel file, this is what i've got. my web.config has <customErrors mode="Off"/> and <identity impersonate="true" /> code creating an instance of the COM component with CLSID {00020820-0000-0000-C000-000000000046} from the IClassFactory failed due to the following error: 8001010a.

An unhandled exception occurred during the execution of the current web request. review the stack trace for more information about the error and where it originated in the code.

Exception Details:
System.Runtime.InteropServices.COMException: Creating an instance of the COM component with CLSID {00020820-0000-0000-C000-000000000046} from the IClassFactory failed due to the following error: 8001010a.

Source Error:

Stack Trace:

[COMException (0x8001010a): Creating an instance of the COM component with CLSID {00020820-0000-0000-C000-000000000046} from the IClassFactory failed due to the following error: 8001010a.] ExcelModule..ctor() +13 _Default.Button1_Click(Object sender, EventArgs e) +33 System.Web.UI.WebControls.Button.OnClick(EventArgs e) +105 System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +107 System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +7 System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +11 System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +33 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5102

anyone knows what to avoid this error?

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Curly Brackets After Creating Instance - Purpose?

Mar 05, 2009 11:47 PM

I have never come accross this syntax before using VB.net... what is the value the goes into the curly brackets??? is there another way this line can be created to show me the meaning of the curly brackets?

somthingOptions = New somthingOptionsType() {something.here}

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Configuration :: Creating An Instance Of The COM Component With CLSID

May 22, 2010 12:03 PM

I Have written code to create instance of an AUTOCAD application.

private void InitializeAutocad()
acApp = (Autodesk.AutoCAD.Interop.AcadApplication)Marshal.GetActiveObject(progID);
Type acType = Type.GetTypeFromProgID(progID);
acApp = (Autodesk.AutoCAD.Interop.AcadApplication)Activator.CreateInstance(acType, true);
catch(System.Exception ex) { }

but it throws the above error.

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Security :: Programmatically Creating User Instance When Servers Are Different

Jan 07, 2011 10:06 AM

I need to create .net membership user instance for a database living in a different server than the one I'm coding in. What is the best way to do this?Should I do it though Sql Server stored procedure? or should I use a separate provider (therefore having 2) in my web.config?

I need to create this user without using the "create user wizard".

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Web Forms :: Dynamically Creating Instance Of Ascx - Controls Not Being Initialized?

Jul 29, 2010 04:12 PM

apologies beforehand for what can possibly be a daft conceptual question. I have an ascx control that has a bunch of ASP labels and buttons in the ascx page and some other public methods and properties in the code behind. When I drop this ascx control in a page it all works fine. I now have a page with a placeholder and I am trying to dynamically create an instance of my ascx control and put it there. I then reference this control in code and while all public methods and properties are available (ie MyControl.TitleString = "Hello";MyControl.DoSomething();) none of the ASP controls are. Rather, they are all null. So MyControl.buttonSave is null, MyControl.LabelTitle is null, etc. Is this by design? Am I missing something? If not, what's the point of being able to create dynamically do this?

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Forms Data Controls :: Creating New Instance Of Chart Displayed In Table

May 05, 2010 12:12 AM

I am building a .net page and need to display some data residing in a database. Some of it's working, some not. I would like to use a table to display the data with the format below..

row - question data
row - answer (count)
row - next answer (count)
row - BarChart representing the answer counts for question
row - next question data
row - answer (count)
row - next answer (count)
row - BarChart representing the answer counts for question

The question data and answer count rows are generated with no issue. However, the rows containing the barchart are problematic. Not sure how to create a new instance of a chart on the fly and hook in all the methods, etc. and get the control added to and displayed in the tablecell. Been looking for examples to create the chart on the fly with no real results.

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Web Forms :: Creating A Dataset But Got An Error / Object Reference Not Set To An Instance Of An Object

Sep 22, 2009 02:51 PM

I used code below to bind dataset to a gridview but sometime got an error:

Object reference not set to an instance of an object

How to fix it


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How To Send Smtp Mail / Error Creating Object Reference:could Not Create Instance Of An Object

Dec 19, 2008 04:10 PM

I m trying to send email from my asp.net page using smtpclient. I m getting an error saying "Error creating object reference:could not create instance of an object.". When i debug, it throws the error at smtpclient.send method.

Here is my code:

MailAddress toAddress = new MailAddress("maran@makefriendsonline.com");
MailAddress fromAddress = new MailAddress(txtEmail.Text.Trim());......

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Visual Studio :: Error When Creating New Report Server Project/object Reference Not Set To An Instance Of An Object

Jun 02, 2007 09:11 PM

When I try to create a new Report Server Project, I receive an error: object reference not set to an instance of an object.When installing the business intelligence files form SQLEXPR_TOOLKIT.EXE a

folder "Microsoft Visual Studio 8" is created in the default drive "C".Presently Visual Studio 2005 is installed in another partition "D". In order for it to work partially I had to copy the folder from "C" to "D". Now when I try to create a new project I receive the error.

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Custom Server Controls :: Using The Generic Type 'System.Collections.Generic.IEnumerable' Requires '1' Type Arguments

Nov 25, 2010 08:41 AM

I'm trying to create a control out of a class I found, and one of the overridden functions is the following:

protected override void PerformDataBinding(IEnumerable data)

However, when I try to build the control I'm getting the error as shown in the subject. I've tried searching, and it seems the signature for the original function matches the one I have, and all other solutions I've seen uses the same signature.

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The Ilist Does Not Contain Any Data Sources?

Jan 11, 2009 10:51 AM

Source Error:


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ADO.NET :: How To Convert IList To Datatable

Nov 05, 2010 02:16 AM

i m developing a Web Application with C# (with NHibernate)

want to bind the IList with the gridview ...for that i hav to convert IList to datatable .

IMPORTANTLY my Database table that i want to pull(through Nhibernate) contains 3 foreign keys now wat to do convert ?

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C# - DropDownList.DataValueField In A IList?

May 13 10 at 15:21

In Asp.Net 3.5, it is possible that the DataValueField is a IList ?

myddl.DataValueField = "ListOfId"

where ListOfId as a IList in my DataSource

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Difference Between Generic And Non - Generic Collection?

Oct 30, 2010 02:44 AM

What is the difference between generic and non-generic collection?

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MVC :: Posting An Array Or IList From A Form

Aug 03, 2009 09:08 PM

I thought I remembered seeing a way to do this somewhere... but I've been searching and I can't find it.I want to pass an array through a form as a hidden form field. It's a list of numeric IDs. I could just use a comma-delimited list (which would work fine), but I thought there was a clever way to actually get an array of ints, or an IList of ints, in my controller when it's posted back to the server. Is there some such way? Do I have to do something funky to my model class? For now I am just manually parsing the string that comes in, and converting it to an IList<int>.

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NHibernate And Binding To A IList Of <Products>?

Nov 16 10 at 6:22

I have recently started to use Nhibernate and i am quite happy with it until i needed to BIND to ASP.NET controls. I was having major issues binding a gridview to a collection of Products (IList). In the end i was forced to right a small routine to convert my IList to a DataTable. Once it was in datatable it worked flawlessy.

Now has come the time to bind a standard Dropdownbox to 1 field of a collection (IList) of Products but it appears i am having issues again.So this has brought me to the conclusion that i must be doing something wrong?I can't believe that it isn't possible to BIND ASP.NET controls to a collection (IList) of a class (in my case products) that is returned from NHibernate.I would really appreciate any feedback anyone has on the situation... I am at a loss

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MVC :: Auto Binding To IList Not Working?

Jun 03, 2009 03:40 PM

I have a very simple MVC project in which I've tried to emulate all the samples I've seen on the web. However, I can't get this to work. Here's my code:


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ADO.NET :: How To Convert DataTable Objects To IList Without Using For Each Loop

Oct 04, 2010 12:15 PM


Can we implement through LINQ ?

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C# - How To Create An Ilist From DataTable With Unknown Columns

Oct 27 10 at 17:05

I have a DataTable that was built from dynamically created SQL, so I do not know the number of columns in the datatable.

How can I convert this datatable into an IList?

EDIT: I am then going to use this to send to a Telerik Grid on the page.

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C# - How To Populate IList <t> From DataTable Or From A Table In Database

Aug 12 10 at 9:55

I have a table say, Student.

I have a class 'Student'.

I want to populate IList<Student> with objects of Student class from Student table in database.

Is it possible to implement this?

If yes then how to implement this.

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XML :: Need To Serialize A Car Object That Contains An IList<Wheel> Collection?

Sep 30, 2009 05:31 PM

I know this is not directly possible without WCF, but do you have any alternative recommendations for what to do when you need to serialize a Car object that contains an IList<Wheel> collection?

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Forms Data Controls :: Binding RadpanelBar With IList?

Mar 23, 2011 03:38 PM

I am trying to bind the panel bar with the IList. I have the follwing code in my class libarry


I need to bind the panel bar with getmenuItems. In the above code DataReviw, Score Rep, Something else, section 2 and sample are the parent node of the panel bar and Test1,


are the childeren of the panel bar and they are the link to another web page.

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Visual Studio :: Adding Properties With StateManagedCollection IList?

Nov 23, 2009 04:36 PM

I've inherited 2 interfaces (StateManagedCollection, IList) in a web control to make a list of items but when I use these interfaces the properties doesn't appears in aspx source editor. But they appears in code view..

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Forms Data Controls :: "Error Creating Control" - Object Reference Not Set To An Instance Of An Object

Apr 27, 2009 03:59 PM

I'm using VS 2005 and recently I added MSChart controls on it. Even I test the samples included on [URL]. My charts have to show data from a DB, so when I tried drop the chart control into the design view appears the error message "Error Creating Control" - Object reference not set to an instance of an object instead of the chart control. I've been tried this on two differents PCs and happens the same.

This happends when I drop the control, I still haven't compiled anything. But when I compile the web site, it compiles!!. Even if I create random data the web site compiles and runs showing the chart, but I want take data from a data source. So, the control is not created then I create a data source and I added it to the chart:


Then I switch to design view, my data source have the error "Error Creating Control" - Object reference not set to an instance of an object also I want to make it clear that the same string connection that i'm using on this data source works perfectly in other web site I'm using VS 2005, framework 3.5 with SP1 and Win XP browsing with firefox

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MVC Default Model Binder - Bind A Multiselect Dropdown To An IList

Sep 13 10 at 18:18

I'm using MVC 2.0 in an ASP.NET application using NHibernate. I have a working View, Controller and data access layer using NHibernate that is able to display and save an entity with a relationship to another mapped entity: Person -- > Location It's using the HTML helper HTML.DropDownListFor() to display a list of all Locations. The user is able to select one of the Locations from the list, and press save. The default model binder correctly sets the value of the Location on the Person entity being saved. This location is an nhibernate mapped entity, and is instantiated and has the id value that was selected in the dropdown list. Obviously, since the dropdown list that holds locations only has the ids of the locations, the rest of the values for the location are null. This is OK. I am only trying to save the Person with a reference to an existing location.

So, here comes the complication. We have a need to change the relationship between the two entities. Now the Person can have a reference to many locations. Person.Locations will be an IList My question is, how do you get the default model binder to take selections from a multiselect dropdown and populate an IList. I've managed to save collections of entities in the past using the syntax [index].PropertyName as explaing by Phil Haacked .... [URL]

The issue here is that I have only a dropdown list, and it will post back to the modelbinder a repeating key with different values:

Person.Location.Id: 2
Person.Location.Id: 4
Person.Location.Id: 5

This, unfortunately, doesn't work. the Location list keeps coming back Null. Our UI guy is using a slick JQuery pluggin to display the items in the select list, so I'd rather not have to use a different UI.

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Forms Data Controls :: Casting The IList Functions Into DataTable?

Jan 21, 2007 06:10 AM

How can I cast the function of IList generic collections into DataTable, as I want to generate data from mySQL database to set them into placeholder?


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Forms Data Controls :: How To Accept An 'object' As A Datasource (IEnumerable Or IList)

Nov 19, 2010 08:15 PM

How do I accept an 'object' as a Datasource (IEnumerable or IList) and loop through the keys/values? I want to be able to pass anything that implements either IEnumerable or IList.

This same functionality exists on all of the .Net DataBound controls and I'm trying to figure out how it's done.


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Visual Studio :: Vs Asp2008 Instance Cant Recognize SqlExpress 2008 Instance On Machine

Feb 06, 2010 09:34 AM

vs asp2008 instance cant recognize the sqlExpress 2008 instance on my machine

I have wonder if you could try to help me with the fallowing issue:When trying to add a new sql server connection (local or remount) from VS(visual studio) 2008 express - on the add connection dialog

box: server name: are Empty!!
The vs couldn't point to any database, like dont recognize the sqlExpress 2008 instance i got on my machine.

1. Have tried to "play" with sa property's(from sqlS: Databases: security: login tree folder) and with the sql

s windows service: stop and restart
2. And so with the target db.

On the services.msc
The sql server express the status is started.
The sql server agent status is disabled and don't have the option to start.
The sql server explorer status is disabled and don't have the option to start.

4. And so reinstalled the asp.

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Architecture :: Singleton With Instance Methods - Instance Is Unique In Each AppDomain Or Across AppDomains?

Dec 19, 2007 04:49 AM

A singleton can have only one instance in memory.

1. Instance is unique in each AppDomain or across AppDomains?
2. I have two Virtual Dirs, and I am using same class. How many instances would be there?
3. If three users are accessing same method from Singleton class, then each will provide difference output. So internally .NET creates Instances of these methods? e.g. A method gets NAME as input param and returns "Welcome NAME !". If three users are accessing same method as same time, then output will be 'WelCome NAME1', 'WelCome NAME2'...NAME3. How it is done?

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