Re: Quick - C# Discussion Boards

Re: Keeping constant strings

11-May-08 7:12

What?!

I've never seen that documented anywhere.

But I just tried it and it seems to be true.
That doesn't make sense.

Edit:

It's true of enum members as well.

I just looked through the specs and saw no mention of this functionality, but I see now that it does make (some) sense.

Among other things, const values are valid in case labels, and case labels must be unique. Changing a const value (or enum) could make a previously-compiled switch invalid.

So, yeah, I think a best practice is; unless the value is an actual constant value like Pi, don't use public const, but use public readonly instead. Using private const, may not be as bad, but the next developer to come along may make your privates public. So use const sparingly.

Thanks for the tip.

modified on Monday, May 12, 2008 11:46 AM

PIEBALDconsult9-May-08 7:21

Re: Keeping constant strings

9-May-08 7:21

Use an enum with Description attributes?

enum Messages
{
    [Description("Message")]
    ServerCommunicationFailure
,
    [Description("Message")]
    AuthenticationFailure
}

N a v a n e e t h10-May-08 23:23

N a v a n e e t h

10-May-08 23:23

Thanks. I will take a look into that.

All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia

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Accessing index arrays via string keys [modified]

MrEyes9-May-08 0:38

9-May-08 0:38

Hello all,

I have an array of a simple object type:

class EntryPoint
{
 private widgets[];

 public EntryPoint()
 {
   this.widgets = new widgets[1000]
   
   ...code here to populate 1000 widgets...
 }
 
 public Widgets[]
 {
   get { return this.widgets; }
 }
}

class widgets
{
 public string key;
 public string value;
}

Now, elsewhere in the the application, I need to be able to extract values from the widgets[] from instances of EntryPoint. However I need to be able to do this using the string key, not the index number. So the question is how can I do this? A hacking but slow way is something like this:

public string GetWidgetValue(string key)
{
  string returnValue = null;

  foreach(widget w in this.widgets)
  {
    if (w.Key == key)
    {
      returnValue = w.value;
      break;
    }
  }
  
  return returnValue;
}

This would work, however as mentioned enumerating through the array for every value request could prove to be slow. So can anybody give me an idea of what to do?

A perfect solution would be to encapsulate the base array with something like a StringDictionary and therefore do something like this:

EntryPoint ep = new EntryPoint();
string value = ep.Widgets["widgetkey"];

So the question is, how to do this?

Obviously the sample above is a simplified version of the question, in reality I am working with an array that is generated by deserialising an XML file into a class generated by the XSD tool. This means that unless I ditch XSD for something else (any suggestions?) I am stuck with integer indexed arrays.

modified on Friday, May 9, 2008 7:23 AM

Christian Graus9-May-08 0:39

9-May-08 0:39

Quick ? What sort of subject line is that ?

The obvious solution is a Dictionary, that's what they are for.

Christian Graus

Please read this if you don't understand the answer I've given you

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

MrEyes9-May-08 0:51

9-May-08 0:51

Christian Graus wrote:
Quick ? What sort of subject line is that ?

An extremely poor one, my error - we all make them from time to time D'Oh! | :doh:

Christian Graus wrote:
The obvious solution is a Dictionary, that's what they are for.

Yes, however as mentioned in the original post, I am working with classes generated by the XSD tool. As such I need underpin the stringdictionary with the simple arrays this tool creates and keep the array and the dictionary in synchronisation as code adds, removes, edits values. Unfortunately this is where I am not sure where to go or what to do.

Christian Graus9-May-08 0:54

9-May-08 0:54

WEll, you really cannot lookup by string unless you build a container that works that way. Why not just build a dictionary at the point of deserialising the list, then use that for lookups ?

MrEyes9-May-08 0:59

9-May-08 0:59

Well thats the idea, wrap the base array with a StringDictionary. However I need to keep the StringDictionary and base array in sync as code adds/edits/removes items regardless of whether this is done by string key on integer index.

So the question is how to do it?

Christian Graus9-May-08 1:01

9-May-08 1:01

I guess you need to write a class which contains an array and a dictionary, so that you only add/remove/access items via the interface of that class, which then ensures they are kept in sync

Or, you could use the Values collection of your dictionary as your plain vanilla list of items ?

MumbleB9-May-08 1:04

MumbleB

9-May-08 1:04

Christian Graus wrote:
The obvious solution is a Dictionary

And they work brilliantly.

Excellence is doing ordinary things extraordinarily well.

MrEyes9-May-08 1:24

Re: Accessing index arrays via string keys

9-May-08 1:24

Yes they do, however what I don't know how to do is encapsulate the XSD tool generate simple array with a StringDictionary while keeping everything in sync and not breaking the (de)serialiser, and therefore allow the following:

string val1 = widget[0]
string val2 = widget["mykey"]

Console.Writeline(val1 == val2)

Which would output true

PIEBALDconsult9-May-08 7:26

Need help with ToolStripContainer

9-May-08 7:26

If you're using XML, use an XmlDocument.

It sounds like your "XSD tool" is causing you more trouble than it's worth.

mcbass9-May-08 0:24

mcbass

9-May-08 0:24

Hi
I have a ToolStripContainer where I only use the top and bottom. I set up serveral ToolStrips that I placed into the ToolStripContainer. The ToolStrips are small enough to fit all in one row (on a normal screen). Now, I like to show/hide these ToolStrips based on user action. And besides shwoing I also like to rearrange them. Now here is the problem. What ever I do they get mixed up and are not displayed at the Location I told them.

Basically I do this :

<br />
int  x = 0;<br />
switch(_type) {<br />
 case PropertiesItemMode.Text:<br />
                    toolStripText.Visible = true;<br />
                    toolStripMedia.Visible = false;<br />
                    toolStripMenu.Visible = false;<br />
                    toolStripPositionProperties.Visible = true;<br />
                    toolStripScaleProperties.Visible = true;<br />
<br />
                    x = 0;<br />
                    if (toolStripInfo.Visible) {<br />
                        x += toolStripInfo.Size.Width;<br />
                    }<br />
<br />
                    toolStripPositionProperties.Location = new Point(x, 0);<br />
                    x += toolStripPositionProperties.Size.Width;<br />
<br />
                    toolStripScaleProperties.Location = new Point(x, 0);<br />
                    x += toolStripScaleProperties.Size.Width;<br />
<br />
                    toolStripText.Location = new Point(x, 0);<br />
<br />
                    break;<br />
                case PropertiesItemMode.Menu:<br />
                    toolStripText.Visible = false;<br />
                    toolStripMedia.Visible = false;<br />
                    toolStripMenu.Visible = true;<br />
                    toolStripPositionProperties.Visible = true;<br />
                    toolStripScaleProperties.Visible = false;<br />
<br />
                    x = 0;<br />
                    if (toolStripInfo.Visible) {<br />
                        x += toolStripInfo.Size.Width;<br />
                    }<br />
<br />
                    toolStripPositionProperties.Location = new Point(0, 0);<br />
                    x += toolStripPositionProperties.Size.Width;<br />
<br />
                    toolStripMenu.Location = new Point(150, 0);<br />
<br />
                    break;<br />
            }<br />
<br />

Any idea what I am doing wrong here ?

Thanks
-Sebastian

Weird "Inconsistent Accessibility" problem [modified]

#realJSOP9-May-08 0:03

#realJSOP

9-May-08 0:03

Here's an example of what I'm doing.

public class MyObject1 {}

public class MyObject2 {}

public class MyData
{
    public MyObject1 myObj1;
    public MyObject2 myObj2;

    public void SetData(MyObject1 ojb1, MyObject2 obj2)
    {
        myObj1 = obj1;
        myObj2 = obj2;
    }
}

public partial class MyForm
{
    private MyObject1 myObj1;
    private MyObject2 myObj2;

    private void MyFunction()
    {
        MyData data = new MyData();
        data.SetData(myObj1, myObj2);
    }
}

I don't understand why this should generate an accessibility error during the compile.

"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

modified on Friday, May 9, 2008 7:26 AM

Re: Weird "Inconsistent Accessibility" problem

Christian Graus9-May-08 0:29

Re: Weird "Inconsistent Accessibility" problem

9-May-08 0:29

Well, this will not compile, as it happens, but once I fix the syntax errors, it builds just fine.

John Simmons / outlaw programmer wrote:
public SetData(MyObject1 ojb1, MyObject2 obj2)

needs to be

public void SetData(MyObject1 obj1, MyObject2 obj2)

#realJSOP9-May-08 1:26

#realJSOP

9-May-08 1:26

Yeah, forgot the void, but it won't compile for me in my app (admittedly much larger and complex than the example I posted).

Re: Weird "Inconsistent Accessibility" problem

tgrt9-May-08 1:49

tgrt

9-May-08 1:49

Probably the best way to check this is to start systematically checking the properties and methods on your publically exposed types that expose something that isn't publically accessible. Obviously, starting with the one that caused the compilation error.

Abstract class with no body

NarVish8-May-08 23:56

NarVish

8-May-08 23:56

If an abstract class contains one method with only declaration and with no body, will it gets executed with no errors? Thanks in advance

Re: Abstract class with no body

John Ad9-May-08 0:27

John Ad

9-May-08 0:27

Hi,

yes the code will be executed as the Abstract Classes are not used to create objects.
An abstract class is designed to act as a base class (to be inherited by other classes). Abstract class is a design concept in program development and provides a base upon which other classes are built.

To know more about the same, please refer to the below mentioned link:

[^]

http://www.codeproject.com/KB/cs/jmabstractclasses.aspx[^]

Hope this helps.

Vinay
ComponentOne LLC.
www.componentone.com

Re: Abstract class with no body

PIEBALDconsult9-May-08 7:41

Re: meta data for assembly

9-May-08 7:41

Well, you can't really execute an abstract method. A class would have to be derived from the abstract class and implement the abstract method. Then you can execute the actual method.

An abstract class may contain a non-abstract method, it will require a body, but that body may be empty (or at least an appropriate return statement).

meta data for assembly

George_George8-May-08 23:52

George_George

8-May-08 23:52

Hello everyone,

Meta data for an assembly describes the exposed and referred types of the assembly. I am wondering the the debug version and release version of the assembly, are the meta data the same or not?

thanks in advance,
George

Christian Graus9-May-08 1:03