.NET (Core and Framework)

Re: 'OptionalField' attribute

5-Dec-06 8:16

The meaning is writed as
"If the member was not serialized, the CLR will leave the members's value null rather than throwing an exception."

Visual Studio does the same thing as if this attribute was not used, so why should anyone use it?
Or is it to garantee compatibility with .Net 1.x?

Scott Dorman5-Dec-06 14:04

Scott Dorman

5-Dec-06 14:04

It is part of the changes made to serialization in .NET 2.0 to help alleviate the versioning issues that can be encountered when dealing with serialized objects.

If you have version 1.0 of your product that serializes an object and then you create version 2.0 of your product that adds new fields, you would get an exception when you tried to deserialize the 1.0 version of the object. By marking the field with the OptionalField attribute, the object will be deserialized properly and the "missing" fields will be null.

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In just two days, tomorrow will be yesterday.

Re: 'OptionalField' attribute [modified]

Hendrik Debedts5-Dec-06 22:32

Re: 'OptionalField' attribute

5-Dec-06 22:32

Strange, I can't simulate an exception, what am i doing wrong?

1. Create a class
2. Create an object instance
3. Serialize this object
4. Add a field to the class (value or reference)
5. Deserialize (I supposed .Net would trow an exception here because there's a new field that isn't serialized, but it doesn't)

I think it's just .Net 1.x that generate an exception

-- modified at 4:58 Wednesday 6th December, 2006

Hendrik Debedts6-Dec-06 0:19

FileSystemWatcher question

6-Dec-06 0:19

S O L V E D

By using 'BinaryFormatter', the .Net Framework 2.0 doesn't give an exception if you do not use the 'OptionalField' attribute.

But if u use the 'SoapFormatter', the meaning of the 'OptionalField' attribute becomes clear.

Alsvha5-Dec-06 5:20

5-Dec-06 5:20

Hiya all.
I instantiated a filesystemwatcher and set it to monitor a directory filtered with a specific file.
Then I made a method which handles the Changed event from the filesystemwatcher.... however when I save/alter the file the watcher monitors - I get the event called twice.

Does anybody know why? Or possible what I need to look for?

Stuart Wells5-Dec-06 6:05

Stuart Wells

5-Dec-06 6:05

When I first used this class I had this problem - but I don't have the problem anymore.

To resolve my issue I no longer listen to CHange event, but to the Created, Renamed and Deleted events instead.

Depends on what you need to know, but these covered my requirements.

Stuart Wells
Software Engineer

Hendrik Debedts5-Dec-06 8:06

5-Dec-06 8:06

It's because a changed-event fires more than you probably expect, for example:
- When you create a file
- When you delete a file
- When you rename a file
- ...

Alsvha5-Dec-06 8:22

5-Dec-06 8:22

I have a file, in which I need to monitor changes, so I can't use any of the others. The file exits, so it isn't because it gets created that the watcher triggers twice.
Both events are the "Changed" event.

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127.0.0.1 - Sweet 127.0.0.1

Luc Pattyn5-Dec-06 12:11

Luc Pattyn

5-Dec-06 12:11

I don't know for sure, but maybe you get one event for the content change, and one for the update of the LastWriteTime ?

Luc Pattyn

Alsvha5-Dec-06 20:49

5-Dec-06 20:49

Hmm - could be, could be.

Dave Kreskowiak5-Dec-06 15:00

Dave Kreskowiak

5-Dec-06 15:00

It depends on the file too. If it's a Word document, for example, you're not opening the orignal file. You actually open a copy of it. When you go to save the changes, the file is actually written to the temporary copy (Changed event), then the original file is deleted (Changed event) and the temporary file is renamed (Changed event) to the orignal filename.

Dave Kreskowiak
Microsoft MVP - Visual Basic

Alsvha5-Dec-06 20:49

PowerPoint effects: How to figure out a current effect name within SlideShowNextBuild event handler?

5-Dec-06 20:49

it's an XML document, opened via notepad.

RichTextBox VS2005

Jon Stroh4-Dec-06 17:47

Jon Stroh

4-Dec-06 17:47

I have a RichTextBox on a winform, it was placed there by dragging from the datasouces page, so it is bound to the datafield that contains rtf formatted text. However when I scroll through records in the database when I come across a data record that has rtf formatting it shows the RTF code as well as the text in the field As such:

{\rtf1\ansi\ansicpg1252\deff0{\fonttbl{\f0\fnil MS Sans Serif;}{\f1\fnil\fcharset0 MS Sans Serif;}}
{\colortbl ;\red0\green0\blue255;}
\viewkind4\uc1\pard\lang1033\b\f0\fs16 #4 Ker Long Heeled --Egg Bar--51/2x63/4\f1 --1/2" wedge\par
\cf1 11/02\cf0 --Changed to Natural Balance shoes \f0\par
}

What do I have to do to get the text only from this field to display?

All I really need to do is extract the text from this field

string text = fRONTRichTextBox.Text; Ithought this returned only the text
string rtf = fRONTRichTextBox.Rtf; I thought this returned the text and rtf code formatting

But..Both return the same value:

{\rtf1\ansi\ansicpg1252\deff0{\fonttbl{\f0\fnil MS Sans Serif;}{\f1\fnil\fcharset0 MS Sans Serif;}}
{\colortbl ;\red0\green0\blue255;}
\viewkind4\uc1\pard\lang1033\b\f0\fs16 #4 Ker Long Heeled --Egg Bar--51/2x63/4\f1 --1/2" wedge\par
\cf1 11/02\cf0 --Changed to Natural Balance shoes \f0\par
}

Thanks Jon Stroh

Re: RichTextBox VS2005

Jon Stroh4-Dec-06 18:20

Jon Stroh

4-Dec-06 18:20

After digging deeper some records are processed by the control corectly, some are not. The ones that are have double back slashes in them are processed corectly
{\\rtf1\\ansi\\deff0{

the ones that show text and rtf formatting code have single back slashes
{rtf1\ansi\deff0{

How can I get the control to show both corectly?

string text = fRONTRichTextBox.Text;
string rtf = fRONTRichTextBox.Rtf;

This code works just fine as long as there are double \\ in the rtf code.

Thanks Jon

wasek20014-Dec-06 2:48

wasek2001

4-Dec-06 2:48

Hello,

here is a function's signatures for 2 PowerPoint effects event handlers:

SlideShowNextClick(SlideShowWindow Wn,Effect ef)
The effect onNextClick is ef.

SlideShowNextBuild(SlideShowWindow Wn)
What is a currently executed effect??

At the moment I have next implementation:

1. By handle SlideShowNextClick store next effect name ("xyz").
2. By handle SlideShowNextBuild execute my bussiness logic (for effect "xyz").

The problem occurs if the current slide has more than 1 effect on page and "go back" button will be used. ==> I can't catch "goback"-event, thus I can't be sure that my stored "NextEffect" is a next effect realy.

Is it possible to get number/name of currently executed effect directly in SlideShowNextBuild handler?

Thanks for your help.

Processname

Alsvha4-Dec-06 1:42