Re: Impersonation in C# question, please help! - C# Discussion Boards

FlamTaps9-Jul-04 7:25

9-Jul-04 7:25

Hello,

I am trying to instantiate a COM object. However, I am having some problems with threading. When I try to instantiate it without any threading statements, as follows:

<br />
public static void Main(String[] args) { <br />
<br />
  Application.Run(new SetupCreator()); <br />
<br />
} <br />
<br />
public SetupCreator() { <br />
<br />
  ESRI.MapObjects2.Core.AxMap map1 = new ESRI.MapObjects2.Core.AxMap(); <br />
  /*....*/ <br />
  this.Controls.Add(map1); <br />
<br />
} <br />

I get the exception: "Could not instantiate ActiveX control '9bd6a64b-ce75-11d1-af04-204c4f4f5020' because the current thread is not in a single-threaded apartment." So, I did some research, and added the line

<code}
[stathread
<="" code="">

to just before main. With that there, I get "There is no source code available for the current location". I found another approach, which adds the line:

<code>
Thread.CurrentThread.SetApartmentState(ApartmentState.STA);

and getting rid of the STAThread line. Now, with this in place, I get "Failed to set the specified COM apartment state." So, I am a little lost as to what to do. Any suggestions?

Re: COM Object

MilesAhead9-Jul-04 8:17

MilesAhead

9-Jul-04 8:17

Have you tried importing it into the
Toolbox and dropping it on the main
form of a test application? Perhaps
if that works you can look at the
Form Designer generated code for clues.

Re: COM Object

FlamTaps12-Jul-04 8:55

FlamTaps

12-Jul-04 8:55

Unfortunatly that did not work. I still need help on this problem. Any other suggestions?

Re: COM Object

Anonymous12-Jul-04 9:37

Anonymous

12-Jul-04 9:37

"that did not work" is kinda' vague.
Could you import the control?
Could you drop it on the form?
Did it give an error msg?

Re: COM Object

FlamTaps12-Jul-04 10:29

FlamTaps

12-Jul-04 10:29

Your right, I appologize. I did import the control, the reference was there. I I drug the control onto the form and looked at the Form Designer generated code. There was very little in difference. Then, I executed the app, and I got the same senario ("There is no source code available for the current location") since the generated code added the "[STAThread]" line.

Re: COM Object

MilesAhead14-Jul-04 14:07

MilesAhead

14-Jul-04 14:07

I don't think I've run across anything like
that. Do you know if the ActiveX was implemented
in VB by any chance? I ask because I've seen
some references to VB ActiveX or COM objects not
being marked with the "creatable" attribute on
some of the Delphi ngs. Other than that I'm afraid
I don't have any idea. Perhaps google on the GUID or CLSID and see if this control shows up in bug reports is all I can suggest.

Sorry I couldn't be more help.

Impersonation in C# question, please help!

garfieldlee999-Jul-04 7:00

garfieldlee99

9-Jul-04 7:00

Hi,

I have a question about impersonation. I'm writing C# in asp.net for a web app. to be deployed on a Windows 2000 Server. I'm writing code to access a file that's located on a network folder. So inside my code, I need to perform "Impersonation" in order to have the client browser access the file. So looking at msdn, they give me the code for Impersonation by means of

LogonUser - > Duplicate Token -> Impersonate

But the problem is that there is a warning in the code snippet comments about executing the code in the windows 2000 environment. It says the code can only be run in Windows XP as there is a security risk if executed in Windows 2000.

MSDN Code Snippet:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfSystemSecurityPrincipalWindowsIdentityClassImpersonateTopic.asp

Can someone please tell me how i can access this file located on the network in Windows 2000 (if i shouldn't be using impersonation)?

Thanks!

Sharon

Re: Impersonation in C# question, please help!

Heath Stewart9-Jul-04 9:04

Heath Stewart

9-Jul-04 9:04

First of all, this question should be posted in the ASP.NET forum, but I'll answer anyway.

Instead of manually impersonating a user by handling the authentication yourself, ASP.NET already has this functionality built-in. By simply adding <identity impersonate="true" /> under the <system.web> configuration section in your Web.config file, you're half-way there. If this is for an intranet, IE will automatically use their domain credentials. You can force NTLM authentication (all handled for you by ASP.NET) by adding <authentication mode="Windows" /> under the same section I mentioned above. Done. Now IE will securely prompt for credentials if the user was not authenticated and will authenticate against the domain.

With your approach, you'd have to prompt for credentials in a web page. If you don't use an SSL certificate to encrypt the transfer, you've made a gaping hole in security because a simple packet sniffer could sniff domain usernames and passwords.

If you want to know how to impersonateusers anyway, lookup WindowsIdentity.Impersonate in the .NET Framework SDK. It provides a thorough example.

Microsoft MVP, Visual C#
My Articles

Property Grid

machocr9-Jul-04 6:53

machocr

9-Jul-04 6:53

Hi, how can I set the cultureinfo to use in the propertygrid?
How can I select which properties of an object to show in the propertygrid? is posible?
Thank you!

La realidad no es más que impulsos eléctricos del cerebro - Morpheus

Re: Property Grid

Heath Stewart9-Jul-04 9:07

Heath Stewart

9-Jul-04 9:07

This is where the .NET ComponentModel comes into play. Read Enhancing Design-Time Support[^] in the .NET Framework SDK for starters, as well as the System.ComponentModel namespace classes.

Filtering the properties (or even "creating" properties) can be done in many ways, such as implementing a designer, a TypeConverter, or implementing the ICustomTypeDescriptor on your object.

As far as the CultureInfo goes, you need to set Thread.CurrentUICulture to the CultureInfo you want on the thread that owns the PropertyGrid instance (the thread that created it).

Microsoft MVP, Visual C#
My Articles

Re: Property Grid

Jay Shankar11-Jul-04 22:26

Jay Shankar

11-Jul-04 22:26

There are few examples in Code project dealing this. You can please refer these.

.NET 2.0's WebBrowser control

Judah Gabriel Himango9-Jul-04 6:32

Judah Gabriel Himango

9-Jul-04 6:32

I was playing with the managed WebBrowser control wrapper included in .NET 2. One seemingly huge bit of missing functionality is when the NewWindow event is launched, I want to open the new window in my code using my control, not using the default browser! What's the deal here, did they forget?

I can use the messy COM interfaces to do this I know, but wow, did they actually forget this functionality or am I missing something?

#include "witty_sig.h"

Re: .NET 2.0's WebBrowser control

Heath Stewart9-Jul-04 9:11

Heath Stewart

9-Jul-04 9:11

They've left quite a bit of stuff out - just like every other class in the BCL. The major functionality is supported, though. You wouldn't want a bloated BCL now, would you? Smile | :)

I would recommend posting this feature request before it's too late by using the new MSDN developer center for VS 2005 and .NET 2.0. Browse to http://lab.msdn.microsoft.com/vs2005/Default.aspx[^]. You'll need a Passport, but you can post bugs and feature requests. This is primarily for VS 2005, but I've seen several .NET 2.0 bugs/requests slip in. You could always use the MSDN newsgroups, too.

Microsoft MVP, Visual C#
My Articles

implement a own shell-view

Shir Khan9-Jul-04 5:23

Shir Khan

9-Jul-04 5:23

*prust*

Is it possible to implement a own shell-view for the Windows Explorer??
I don't want to create my own Explorer, but I need a special view to present the content of a folder to the user. Its possible to add a column to the details view of the Explorer window, but I need more.

I wrote a programm that analyses methods out of Java-Source files (*.java). Each found method in a file should get its own entry in a listview. Therefore I can not use the details view of the explorer. I need my own view.

I don't know if that is possible. But if its possible, how should I implement this "owner-drawn" view????

Shir Khan, the tiger
GVT

Re: implement a own shell-view

Jesse Squire9-Jul-04 5:36

Jesse Squire

9-Jul-04 5:36

MSDN Magazine had an article[^] in the January 2004 edition about writing shell extensions in .NET. I'm not sure that it is 100% applicable, but perhaps it can provide a starting point.

Hope that helps a bit. Smile | :)

--Jesse

Re: implement a own shell-view

Nick Parker9-Jul-04 6:00

Nick Parker

9-Jul-04 6:00

Shir Khan wrote:
Its possible to add a column to the details view of the Explorer window, but I need more.

That is correct, you can do this through a shell extension (Mike Dunn has written a nice article here[^]). However since you need more I would suggest you read Dino Esposito article on MSDN titled: More Windows 2000 UI Goodies: Extending Explorer Views by Customizing Hypertext Template Files[^]. I would caution you that soemthing like this would probably best be written in an unmanaged language, otherwise you are looking at a lot of additional work. Good luck.

- Nick Parker
My Blog | My Articles

Data layer DLL .Config

Andy H9-Jul-04 4:58

Andy H

9-Jul-04 4:58

I am writing a DataBase layer DLL and I am having toruble reading the Config file to get the ConnectionString etc. To enable me to read the Config file with:

_connectionString = ConfigurationSettings.AppSettings[ "ConectionString" ];

from within my DataBase layer DLL what do I need to call the Config file and where do I put it so that it will read from this Config file both while debugging and when running the .exe which will create an object of the DataBase layer.

My Config file is as follows:

<?xml version="1.0" encoding="utf-8" ?><br />
<configuration><br />
	<appSettings><br />
		<add key="ConectionString" value="testing"/><br />
	</appSettings><br />
</configuration>

Re: Data layer DLL .Config

Heath Stewart9-Jul-04 9:16

Heath Stewart

9-Jul-04 9:16

The default executable loader does not load .config files into the AppDomain for DLLs - only EXEs. You either need to create your own loader or shim, or document that the host application must define an appSetting named "ConnectionString" in its .config file (which is a common approach, or error out).

Microsoft MVP, Visual C#
My Articles

Find on Page with IE browser control

weekly_s9-Jul-04 4:47

weekly_s

9-Jul-04 4:47

Hi all. I am working on a project where we have an embedded IE control on a Windows form, and one of the features we have been requested to produce is a " find on this page", where the user can type in a term, and if it exists, the browser control will scroll to it (similar to the existing functionality of IE's Edit->Find( on this page), without the dialog). the problem I am getting is that I see no elegant way of doing this, without parsing the HTML returned in the browser control, or wrapping a Javascript in some form of COM interop. Seems that there should be some method exposed in the Windows Browser control (mshtml.dll) for doing this, but I can't find it. All we need is for the method to take a string, and look for it on the displayed page. If it finds it, show it, otherwise, pop up a message box.

Any help in this matter will be greatly appreciated.

Re: Find on Page with IE browser control

Heath Stewart9-Jul-04 6:18

Heath Stewart

9-Jul-04 6:18

If you haven't already, you'll need to interop MSHTML. If you've installed VS.NET, Microsoft.mshtml.dll should already be in the GAC. You just need to add a reference (this contains all the automation interfaces for the DOM).

Get the IHTMLDocument2 reference by casting WebBrowser.Document to the interface. Then get the body property (an IHTMLElement). Cast this to an IHTMLBodyElement and call createTextRange. This gives you an IHTMLTxtRange. You're almost done.

Call findText on the IHTMLTxtRange. Documentation for this method can be found in the Web Develoment -> Programming and Reusing the Browser section in MSDN Library[^]. If the text is found (it returns a bool), the IHTMLTxtRange is modified to beginand end with the text that was found. Then simply call scrollIntoView on the IHTMLTxtRange, passing either true or false to position the text at the top or bottom of the window, respectively.

Microsoft MVP, Visual C#
My Articles

Re: Find on Page with IE browser control

weekly_s9-Jul-04 7:55

weekly_s

9-Jul-04 7:55

Thanks so much, this works great. I have one other quick question, how can I cycle down the document if more then one instance of the string is found? Say if they hit the button agai, it goes to the next instance, until findText returns false?

Re: Find on Page with IE browser control

Heath Stewart9-Jul-04 8:54

Heath Stewart

9-Jul-04 8:54

I again encourage you to read the MSHTML Reference[^] documentation I mentioned earlier if you haven't already.

The easiest way would be to call IHTMLTxtRange.moveStart to move to the end of the range, then call IHTMLTxtRange.moveEnd to move to the end of the body (there's many ways to do this). Then call findText again and repeat the process.

Microsoft MVP, Visual C#
My Articles

Limiting the bandwidth

pi_trek9-Jul-04 1:09

pi_trek

9-Jul-04 1:09

Hi!

I'm looking for any information on how to limit the internet bandwidth used by my program. I have found that this can be done by delaying ACK packet, but how can I do it from .NET framework (I dont want to use any unsafe code)

Thanks in advance
Piotrek

Re: Limiting the bandwidth

Dave Kreskowiak9-Jul-04 6:07

Dave Kreskowiak

9-Jul-04 6:07

The .NET Framework languages we're not designed for such low level work. You would have to P/Invoke many API's and declare bunches of constants and structs to do it. There is no support in the .NET Framework for doing what your talking about. Everything about this project would be unsafe code...

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Re: Limiting the bandwidth

pi_trek10-Jul-04 3:54

pi_trek

10-Jul-04 3:54

Thanks

Is it possible to limit (control) bandwidth in this way:

1. set socket buffer through the SetSocketOption and SocketOptionName.ReceiveBuffer to small value
2. do not take data from function call by the BeginReceive and/or do not call BegineReceive again

This should (I think) make full all buffers and the system should send same delaing packets waiting for me to make empty the buffers.

If it isnt possible could You point out some articles/codes about bandwidth limiting, please?

Thanks in advance
Piotrek

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