C# Discussion Boards - CodeProject

Ray Hayes5-Jan-02 4:38

5-Jan-02 4:38

Does anybody know what the correct behaviour the proxy settings when using a HttpWebRequest/HttpWebResponse pairing should be?

Looking on the web I can see many articles (well a few) showing how to instruct a request to go through a proxy. The problem is, to me it already looks that way.... my programs, without abything extra, use the IE proxy settings.

I can change the proxy quite easily, but to bypass the proxies, the best I can come up with is something like this:

bool proxyDetected = 
   ((WebProxy)GlobalProxySelection.Select).Address != null;

if ( proxyDetected && bypassProxy )
  GlobalProxySelection.Select = GlobalProxySelection.GetEmptyWebProxy();

I'm confused! Everybody else seems to want to know how to use a proxy, I'm trying to find another example of someone trying to bypass a proxy! Does the above code look right?

Regards,
Ray

ASP.NET

Matt.W.3-Jan-02 11:59

Matt.W.

3-Jan-02 11:59

Hi folks,

what would be the best way to implement a page header (eg The Code Project's) on each page of a C# WebForm application?

Matt
------
Accept that some days you are the pigeon and some days the statue.

CacheItemRemovedCallback Problems

Tim Bajz3-Jan-02 3:13

Tim Bajz

3-Jan-02 3:13

Guys,

I am having problems with the use of the CacheItemRemovedCallback event within an ASP.NET/C# website I am building. The below code is from my global.aspx file. The code loads XML/XSL objects into the Cache for later use. I also create a Cache dependency so should any files change which my XML/XSL objects use, the Cache is updated automatically. The code works only when something is removed from the Cache by another aspx file, since the code correctly identifies the HttpContext. However, when one of my files is changed and the RemovedCallback() function is fired, for some reason the Context and the HttpContext are both null. As such my code never has a chance to update the Cache again. Rather it exists "without an error" as soon as I try to use Cache.Insert. Does anyone know if this is a bug in Beta 2, or am I missing something, like the use of a special Context object?

Any help greatly appreciated..........

Cheers,
Tim.

<%@ Import Namespace="System.Xml.Xsl" %>
<%@ Import Namespace="System.Xml.XPath" %>
<%@ Import Namespace="System.Web.Caching" %>
<%@ Import Namespace="CommerceEngine.Common" %>

private static CacheItemRemovedCallback onRemove = null;
private XPathDocument CommerceListXmlObj;
private XslTransform CommerceListXslObj;

public void Application_OnStart()
{
ApplicationConfiguration.OnApplicationStart(Context.Server.MapPath( Context.Request.ApplicationPath ));
onRemove = new CacheItemRemovedCallback(this.RemovedCallback);

CommerceListXmlObj = new XPathDocument(CommerceEngineConfiguration.CommerceListXmlFilePath);
HttpContext.Current.Cache.Insert("CommerceListXmlObj", CommerceListXmlObj, new CacheDependency (CommerceEngineConfiguration.CommerceListXmlFilePath), DateTime.Now.AddHours(1), TimeSpan.Zero, CacheItemPriority.Default, CacheItemPriorityDecay.Slow, onRemove );

CommerceListXslObj = new XslTransform();
CommerceListXslObj.Load(CommerceEngineConfiguration.CommerceListXslFilePath);
HttpContext.Current.Cache.Insert("CommerceListXslObj", CommerceListXslObj, new CacheDependency(CommerceEngineConfiguration.CommerceListXslFilePath), DateTime.Now.AddHours(1), TimeSpan.Zero, CacheItemPriority.Default, CacheItemPriorityDecay.Slow, onRemove );
}

public void RemovedCallback(String k, Object v, CacheItemRemovedReason r)
{
switch(k)
{
case "CommerceListXmlObj" :

CommerceListXmlObj = new XPathDocument(CommerceEngineConfiguration.CommerceListXmlFilePath);
HttpContext.Current.Cache.Insert("CommerceListXmlObj", CommerceListXmlObj, new CacheDependency(CommerceEngineConfiguration.CommerceListXmlFilePath), DateTime.Now.AddHours(1), TimeSpan.Zero, CacheItemPriority.Default, CacheItemPriorityDecay.Slow, onRemove );
break;
}
}

Console app question

Krista Crawley-Archer3-Jan-02 2:37

Krista Crawley-Archer

3-Jan-02 2:37

I know this is beginner-level, but how can I write a console app with Visual Studio, run the app and have the output redirected to the Visual Studio output window? If I can't do that, is there another means of pausing the application without calling a getchar() type function?

bye bye,
KLC

Re: Console app question

James T. Johnson4-Jan-02 11:46

James T. Johnson

4-Jan-02 11:46

You can use the trace functions to get your text to the output window.

System.Diagnostics.Trace

I don't think there is one-line method of changing all System.Console.WriteLine's to use the output window.

But you could write a class that implements/extends System.IO.TextWriter (using the Trace class as your backend) then use System.Console.SetOut, passing in an instance of your new class.

HTH,

James

Sonork ID: 100.11138 - Hasaki

Re: Console app question

Krista Crawley-Archer4-Jan-02 11:50

Krista Crawley-Archer

4-Jan-02 11:50

Thanks James, but both methods requires a lot of changing of code that doesn't need to be changed. I was hoping for at least a way in Visual Studio to route all Writelines to the output window. Oh well.

Thanks anyway.

bye bye,
KLC

Re: Console app question

James T. Johnson4-Jan-02 13:13

James T. Johnson

4-Jan-02 13:13

I didn't look into it too much when I replied (was busy putting the finishing touches on an article).

Here's a class that'll do what you want Smile | :)

using System;
using System.Diagnostics;

namespace ConsoleRerouter
{
	/// <summary>
	/// Summary description for OutputToTrace.
	/// </summary>
	public class OutputToTrace : System.IO.TextWriter
	{	
		public OutputToTrace()
		{
			
		}

		public override void Write(char c)
		{
			Trace.Write(c, "Console");
		}

		public override void WriteLine(string line)
		{
			Trace.WriteLine(line, "Console");
		}
		
		private System.Text.Encoding enc = new System.Text.ASCIIEncoding();
		public override System.Text.Encoding Encoding
		{
			get
			{
				return enc;
			}
		}
	}
}

If you do anything really vigorous you'll have to add more calls to Trace.Write/WriteLine, but it'll do the deed as it is right now.

Use it like
System.Console.SetOut(new ConsoleRerouter.OutputToTrace());

It worked great in my simple test (output everything that was typed in)

Enjoy,

James

Sonork ID: 100.11138 - Hasaki

Re: Console app question

Valer BOCAN24-Jan-02 21:17

Valer BOCAN

24-Jan-02 21:17

Run the program by pressing CTRL+F5. The command-line window will request you to press a key before terminating. Blush | :O

casting (headaches)

Senkwe Chanda3-Jan-02 0:22

Senkwe Chanda

3-Jan-02 0:22

Hi guys...here's my problem. I have created a viual control called a TilePlaceControl. I have added many of these to a panel control on a form.

Now, I can access any control containedby the panel in this way...

myPanel.Controls[x] where x is the 0 based index of the control previously added. The problem is, that snippet of code as it stands returns (and rightly so) a generic Sytem.Forms.Control object.

My problem is that I need to change an aspect of the TilePlaceControl actually contained within the panel...for example, I need to do something like this...

myPanel.Controls[x].MyMethod(...)

So then, why can I NOT do this?

(TilePlaceControl)myPanel.Controls[x].MyMethod(...)

The compiler complains saying that MyMethod is not a member of System.Forms.Control.

I wouldn't mind so much if I could simply do the following...

TilePlaceControl tpc = (TilePlaceControl)myPanel.Controls[x];
tpc.MyMethod(...)
myPanel.Controls[x] = tpc;

But I can't because Controls[x] is a READ ONLY indexer.

Please guys give me a way around this, the other alternative is just way too ugly to even contemplate

Regards,

Senkwe

Confused | :confused:

Just another wannabe code junky

Re: casting (headaches)

James T. Johnson3-Jan-02 0:42

James T. Johnson

3-Jan-02 0:42

Senkwe Chanda wrote:
(TilePlaceControl)myPanel.Controls[x].MyMethod(...)

Almost have it!

((TilePlaceControl)myPanel.Controls[x]).MyMethod(...)

That will give you what you want Smile | :)

[Note the extra set of parenthesis]

Senkwe Chanda wrote:
TilePlaceControl tpc = (TilePlaceControl)myPanel.Controls[x];
tpc.MyMethod(...)
myPanel.Controls[x] = tpc;

So close, yet again Smile | :)

You shouldn't have to assign back into the collection unless you actually want to change the instance in the collection in which case you should do a Controls.Remove and Controls.Add.

The code below should work, and give you the results you expect, as will the code at the top.

TilePlaceControl tpc = (TilePlaceControl)myPanel.Controls[x];<br />
tpc.MyMethod(...)

James

Sonork ID: 100.11138 - Hasaki

Re: casting (headaches)

Senkwe Chanda3-Jan-02 0:53

Senkwe Chanda

3-Jan-02 0:53

Thanks alot James, your first code snippet works great and is even clear now that I see it in black and white.

As for your last piece of code

TilePlaceControl tpc = (TilePlaceControl)myPanel.Controls[x];
tpc.MyMethod(...)

I thought of that but then thought that

TilePlaceControl tpc = (TilePlaceControl)myPanel.Controls[x];

creates a seperate instance of the object and hence, tpc.MyMethod(...) would still not be called on the instance contained by the panel.

But I'll explore that again.

Thanks alot!!

Regards

Senkwe

Just another wannabe code junky

Re: casting (headaches)

James T. Johnson3-Jan-02 1:07

James T. Johnson

3-Jan-02 1:07

Senkwe Chanda wrote:
I thought of that but then thought that

TilePlaceControl tpc = (TilePlaceControl)myPanel.Controls[x];

creates a seperate instance of the object and hence, tpc.MyMethod(...) would still not be called on the instance contained by the panel.

Nope, tpc is only a reference to the object. A reference is similar to a pointer in C/C++ and ByRef in VB; anything you do to the reference (except assignment) will carry through to the actual instance.

Assignment on a reference only makes the reference refer/point to something else, leaving the original intact.

The only way to create a new instance is via the new keyword or through reflection's Activator.CreateInstance, neither of which you show here Smile | :)

James

Sonork ID: 100.11138 - Hasaki

Instr

2-Jan-02 14:04

What is the equivalent of VB's "InStr" function in C#?
Wink | ;)

Re: Instr

James T. Johnson2-Jan-02 18:14

James T. Johnson

2-Jan-02 18:14

use the IndexOf method on your string object.

int instr = myString.IndexOf("moo", 0);

There are 5 other overloads that you can use as well, 3 to find a string, 3 to find a char.

James

Sonork ID: 100.11138 - Hasaki

obtaining drive information

hotlemonade2-Jan-02 13:47

hotlemonade

2-Jan-02 13:47

Hello,
I need some information on where to find and obtain a drives attributes, e.g, ROM_DRIVE or FLOPPY_DRIVE etc and other attributes pertaining to the drive. I've searched the MSDN library and other places to no avail. I've tried using Environment but can't get anything. Any insight would greatly be appreciated.

Thanks

Win32 APi with C#

kasturirawat31-Dec-01 13:54

kasturirawat

31-Dec-01 13:54

Any sample on using CreateWindow API from c# ? I’m aware of “MessageBox” sample on MSDN but I’ve no idea on how to retrieve HWND of Form and Instance handle. I’m trying to put together code to use virtual listview. virtual listview is available in SDK not with .Net. Any idea would be truly appreciated.

Thanks

Re: Win32 APi with C#

James T. Johnson31-Dec-01 19:59

James T. Johnson

31-Dec-01 19:59

kasturirawat wrote:
...I’ve no idea on how to retrieve HWND of Form and Instance handle.

For the HWND use the Forms Handle property. The HINSTANCE is a bit harder to get, but still possible.

untested code, but from the docs this should work; though the GetHINSTANCE method confuses me a bit as i'll explain later.

<br />
IntPtr hInstance = System.Runtime.InteropServices.Marshal.GetHINSTANCE(<br />
     typeof(ClassThatHasYourHInstance).Module <br />
);<br />

Here's the confusing part about this method

Parameters
    m 
        The module whose HInstance is desired. 
Return Value
    The HInstance for m;-1 if the module does not have an HInstance.

Remarks
    Whether dynamic or in-memory, modules do not have an HInstance.

It looks like this method will work until you read the remarks. We pass in the module whose hinstance we wish to retreive, but then the remarks tells us that modules don't have one. Thus we will always get -1.

Confused | :confused:

I seem to vaguely remember there being some win32 function that would give you the hinstance if you had the hwnd. Since you have the hwnd you could call this function and get the hinstance (call via p/invoke).

HTH,

James

Sonork ID: 100.11138 - Hasaki

Re: Win32 APi with C#

kasturirawat2-Jan-02 6:39

kasturirawat

2-Jan-02 6:39

I’ve created sample for virtual listview using SDK. Since dotnet does not support virtual list view, is there any way I can use my sdK sample with dotnet app. Using PINVOKE is very time consuming

Re: Win32 APi with C#

James T. Johnson2-Jan-02 9:50

James T. Johnson

2-Jan-02 9:50

I believe you could wrap your code with MC++ providing an interface for your dotnet app to work with it. Thats about the extent of my knowledge on MC++ though. :p

Perhaps someone with a better grasp could fill you in more? Smile | :)

James

Sonork ID: 100.11138 - Hasaki

TAPI

31-Dec-01 4:27

Do Anyone know how to use TAPI in C# or any component in .Net that enable Voice over IP application??????? Confused | :confused:

Automating MS Office97/2000/XP with same C# Code

29-Dec-01 1:41

Hi,

Can any one tell me how I can Automate MS Office 97/2000/XP using the same C# Code. Using VB I could use Late Binding to do this, but I can not figure out how to do it using C#. I wish to have one C# Program which will work on all versions of MS Office.

Thanks for your time

Peter Tewkesbury

Peter Tewkesbury

Re: Automating MS Office97/2000/XP with same C# Code

James T. Johnson30-Dec-01 19:59

James T. Johnson

30-Dec-01 19:59

Just off the top of my head, so i have no idea how much work this would be...

Abstract the functionality you need from office into an interface or abstract class. Then write a class for each version of office. At runtime detect which version of office is installed and use the proper class.

You might have to break each class into a separate assembly so it won't try loading office 97 typelib info when you want xp info. My knowledge of how the references get loaded is minimal though, so this may be an extraneous step.

Hope this at least gives you some ideas,

James

Sonork ID: 100.11138 - Hasaki

Re: Automating MS Office97/2000/XP with same C# Code

Peter Tewkesbury2-Jan-02 5:49

Peter Tewkesbury

2-Jan-02 5:49

Thanks for the info. I now have a working solution thanks to .NET

1. Write the base class in C# in a seperate DLL & namespace

2. Derive a new class in VB from the base class in another DLL - I can use Late Binding features of VB to automate MS Office (All Versions) without writing pages of code.

3. Use this new class in the top level program (C#)

All Thanks for .NET

Man I love .NET
Smile | :)

Peter Tewkesbury
Developer
ibsl technologies

Writing a custom Grid control and need help coding the scrolling events

hsd28-Dec-01 10:01

hsd

28-Dec-01 10:01

I am writing a custom Grid and can't figure how to get the scrolling to work.

I am trying to call ScrollWindow from CSharp and it doesn't seem to be doing anything. I am not getting any exceptions. Can anyone explain what the expected results should be or tell me what i am doing wrong.

Any help would be great!!!!

Code: [DllImport("User32.dll")] public extern static bool ScrollWindow(IntPtr hWnd, int nXAmount, int nYAmount, ref RECT rectScrollRegion, ref RECT rectClip);

public struct RECT {
public int bottom;
public int top;
public int left;
public int right;

public RECT(int left, int top, int right, int bottom) {
this.left = left;
this.top = top;
this.right = right;
this.bottom = bottom;
}

}

/***************/

RECT rect = new Rect(102, 2, 770, 381); bool b = NativeMethods.ScrollWindow(this.Handle, change, 0, ref rect, ref rect);

Re: Writing a custom Grid control and need help coding the scrolling events

James T. Johnson30-Dec-01 20:16

James T. Johnson

30-Dec-01 20:16

I think you're doing too much work on your own here. Windows Forms provides a ScrollableControl class (as well as Panel and ContainerControl).

If you have your control inherit from one of those the scrolling will be taken care of for you, you can set the current position with the AutoScrollPosition property (assuming you have autoscrolling enabled).

Now sure off hand what sets the bounds for scroll, my first guess would be something with the AutoScrollMinSize property.

HTH,

James

Sonork ID: 100.11138 - Hasaki

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.