Re: Reflection Assistance please! - C# Discussion Boards

14-Jun-04 6:43

When possible, set Thread.IsBackground to true on threads you create. See the .NET Framework SDK for more information about this property.

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Re: Unloading AppDomain

Ami Bar14-Jun-04 10:35

Ami Bar

14-Jun-04 10:35

It doesn't work, since the difference between foreground and background threads only affects the way the application exits, and not the way an AppDomain is unloaded.

MSDN: Thread.IsBackground : "A thread is either a background thread or a foreground thread. Background threads are identical to foreground threads, except that background threads do not prevent a process from terminating. Once all foreground threads belonging to a process have terminated, the common language runtime ends the process by invoking Abort on any background threads that are still alive."

What I want to do is to "kill" the AppDomain gracefully, without the need to do anything special within the AppDomain, and changing the way of threads creation is one of them.

I can't believe that I am the first person that gets to this problem. If you can’t “kill” an AppDomain then what is its advantage over a process?

Re: Unloading AppDomain

Heath Stewart14-Jun-04 11:01

Reflection Assistance please!

14-Jun-04 11:01

Ami B. wrote:
I can't believe that I am the first person that gets to this problem. If you can’t “kill” an AppDomain then what is its advantage over a process?

You're probably not - try googling for others.

An AppDomain is an application boundary where assemblies are isolated from each other except through .NET Remoting and proprietary methods (sockets protocols, etc.). ASP.NET uses AppDomains so that when the Web.config file changes, an AppDomain is killed and new one respawned - all from another AppDomain started by the worker process. This allows the process to continue to run and an AppDomain to monitor the change status of the Web.config file so that it can respawn an AppDomain for the ASP.NET web site.

Executing threads must be aborted when the AppDomain needs to be unloaded. This may require changes in the assemblies you're loading, such as spawning threads for I/O, etc., or using async calls.

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Kasdoffe14-Jun-04 5:23

Kasdoffe

14-Jun-04 5:23

Very simple example of what I want to do.

I have a textbox on my form:
TextBox textBox1 = new TextBox();

I have a string containing the name of my textbox:
string strControlName = "textBox1";

I have a string that contains the text for my textbox to display:
string strControlText = "Hello World";

How do i use strControlName and strControlText to set my textbox's text property? (without looping through my controls on the form and using if statements).

In another language I know, you can use 'Indirection'. It's a very useful and powerful tool. This acts similar to the following:
set (@strControlName).Text = strControlText
where the end result is textBox1.Text = "Hello World".

I would love to be able to do this in C#! I was told to read up on reflection, but couldn't find what I wanted. Is there somehow a way to modify an existing control when all you know is the control name? (without looping through all the controls) Please help!

Heath Stewart14-Jun-04 6:38

14-Jun-04 6:38

It depends - is the TextBox a field or property declared in your container (i.e., Form, UserControl, etc.) or is it simply a variable? Reflection only works on type metadata, so if it's a variable it won't work.

If it is a field, then you could do something like this:

public void SetText(string name, string text)
{
  FieldInfo field = this.GetType().GetField(name);
  if (field != null)
  {
    PropertyInfo prop = field.FieldType.GetProperty("Text");
    if (prop != null && prop.CanWrite)
    {
      object obj = field.GetValue(this);
      prop.SetValue(obj, text, null);
    }
  }
}

This also works best when you don't specify the Name properties of controls, which isn't required (the designer does, though).

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Anonymous14-Jun-04 7:02

Anonymous

14-Jun-04 7:02

the TextBox is an actual control that I placed on my form. Does that help?

I tried your code, but field is returned as null when I do the this.GetType().GetField(name).

Heath Stewart14-Jun-04 8:46

14-Jun-04 8:46

That should be:

FieldInfo field this.GetType().GetField(name,
  BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);

This will include non-public (i.e., private or protected) members in the search as well.

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Kasdoffe14-Jun-04 7:37

Kasdoffe

14-Jun-04 7:37

I think I understand what you're doing here, except for the last 2 lines. I don't have the object reference for my textbox. All i have is the name of the textbox. I need to be able to get this reference and set the text property on my textbox control.

looking for a tool or utility

Kasdoffe14-Jun-04 8:32

Kasdoffe

14-Jun-04 8:32

Kasdoffe wrote:
I think I understand what you're doing here, except for the last 2 lines

Nevermind, I'm dumb Smile | :)

Anyways I got it to work like you showed except I had to add BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public as the second parameter to the GetField() method.

Thanks for your help! This is awesome!

Anonymous14-Jun-04 4:54

Anonymous

14-Jun-04 4:54

I am not looking to create, rather I am more looking for advice on something to buy.

I would like to be able to scan in paper forms and use a tool to convert the image into a form that C# can use.

If such a tool does not exist, can you point me towards a tool that would build HTML or other interface from a paper form.

thanks

Re: looking for a tool or utility

Dave Kreskowiak14-Jun-04 5:07

Dave Kreskowiak

14-Jun-04 5:07

Anonymous wrote:
convert the image into a form that C# can use.

What do you mean by "use"? What do you want to do with the information off of the form? Are we talking about filling in items on a Windows Form or are you trying to do Windows Form layout?

I'm assuming layout since you mentioned
Anonymous wrote:
If such a tool does not exist, can you point me towards a tool that would build HTML or other interface from a paper form.

I've never heard of such a tool. And, frankly, can't image how something like this would even work considering the complexities of an HTML form that just can't be described by an image on a piece of paper.

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

RichTextBox selection color

Judah Gabriel Himango14-Jun-04 4:31

Judah Gabriel Himango

14-Jun-04 4:31

When I select some text in a RichTextBox, the control draws a filled blue rectangle around the selected characters. It appears that .NET doesn't allow this color to be changed. Is there a way to do this through either .NET calls or P/Invoke?

#include "witty_sig.h"

Re: RichTextBox selection color

Heath Stewart14-Jun-04 4:49

Re: RichTextBox selection color

14-Jun-04 4:49

Take a look at the RichTextBox.SelectionColor property.

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Judah Gabriel Himango14-Jun-04 5:02

Judah Gabriel Himango

14-Jun-04 5:02

That changes the color of the selected text, not the selection rectangle drawn by the control.

Is there a way to change the color used to highlight the text (i.e. the blue rectangle drawn over the selected text)?

#include "witty_sig.h"

Upload files using SPS 2003

Member 67053114-Jun-04 4:16

Member 670531

14-Jun-04 4:16

Hi,
Can any one suggest me how to upload a file using MS SharePoint Portal Server(SPS) 2003 components (using web services for uploading and check in/out documents). Please provide me with the sample code if you have

Devikiran

Using System.Data

Simon Wren14-Jun-04 4:08

Simon Wren

14-Jun-04 4:08

Hi all,

I'm no database programmer, hence i don't need a "using" for "System.Data" so obviously i remove it at the start of the project both in the code and the reference section.

Why is it that everytime after that when i add a class to the project it gets re-referenced and put in the new class?

Is there anyway to configure what is included in the "using" section when a new class is auto generated?

Thanks in advance

Re: Using System.Data

Heath Stewart14-Jun-04 4:30

Embedded User Control in IE Problem

14-Jun-04 4:30

Don't worry about it. If an assembly reference is not used when the project is compiled, it is not included as an assembly dependency in the generated assembly. You could, for example, add every single assembly on your machine as an assembly reference, compile your project, and still only the assemblies that are actually used will be referenced in the assembly manifest. The same goes for imported namespaces (which is really just a language feature that makes programming easier - it doesn't matter when linking the assembly).

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Yolan14-Jun-04 3:45

Yolan

14-Jun-04 3:45

I have been working on getting user control embedded in IE, unfortunately I have ben unsuccessful. So far I have written the control, replaced the system colors with standard colors (web colors black and silver). I have gone to the server and using the .NET wizards trusted the assembly, I have also tried using the configuration to trust the assemblies, I have signed the assemblies, and tried not signing. I have added full trust to the intranet (the control won't even load on the local machine). Here is a message I sent asking for help and the response I got (much appreciated by the way if you have any more ideas I'm all ears Smile | :)

)

--------------
Hi, I've been trying to get my embedded user controls working for a couple days now and have not had any success. The problem I'm having is that instead of anything showing, I get the image loading icon in a recessed object. I have followed three tutorials including one from 4guysfromrolla, the .NET SDK sample, and your tutorial. I have even downloaded source of projects that definately work and have had the same results. Is there a setting on my server that I may have missed? I have included a screenshot of the results I get just to be clear on my error. I have also included the line from my logs that I recieve when someone accesses the page. Any advice you can offer would be much appreciated.

Either you haven't given that URL the necessary permissions using the Microsoft .NET Framework Configuration snap-in in the Control Panel->Administrative Tools (or use caspol.exe), or you're forgetting that system colors cannot be used by your control or any other controls within your control, and so on.

Code access permissions are important to remember. If you don't grant the necessary permissions based on the evidence (and only host evidence and the strong name evidence are gathered when embedded a control in IE), the control won't run. This is a "sandboxed" environment, remember.

The problem with system colors I've never been able to figure out, and despite my relationship with Microsoft no one there can give me a straight answer either.

--------------
Anyway, thanks in advance for anymore help that anyone can offer.

Yolan

Heath Stewart14-Jun-04 3:56

14-Jun-04 3:56

The client has to trust the assembly, not the server. You must use the Microsoft .NET Framework Configuration MMC snap-in on the client machine to trust the URL of the assembly, or use caspol.exe (the command-line utility). The server doesn't need to trust the assembly - it's only hosting the control and not executing it. Assemblies need to be trusted on the machines on which they'll run.

As I mentioned in my email before, you should read Understanding .NET Code Access Security[^] for a better understanding.

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Yolan14-Jun-04 4:09

Yolan

14-Jun-04 4:09

I had also configured it locally to trust the dll(forgot to mention that, sorry). I used Runtime Security Policy->Machine->Code Groups->All_Code and added a new code group for my source. I used the full_trust option, but it still had no effect.

Heath Stewart14-Jun-04 4:24

14-Jun-04 4:24

Yes, but which membership condition did you use? As I mentioned in my email, only host evidence and strong name evidence are supported by IEExec.exe, the runtime CLR host for Internet Explorer. Other evidence is not gathered.

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