C# Discussion Boards - CodeProject

Blubbo2-Jul-07 3:13

Re: RichTextField control issue [modified]

2-Jul-07 3:13

Weird eh?

Same issue for Clear() method.

again, weird eh?

Blubbo2-Jul-07 3:17

2-Jul-07 3:17

P.S. This is how I populate the rich text field... the length of dataHexDump could be 256 or 512 bytes length. 512 bytes length does show vertical scroll bar automatically.

<code snippet>
for (int line = 0; line < (memSize / 16); line++)
{
for (int col = 0; col < 16; col++)
rtfDumpResult.Text += dataHexDump[line * 16 + col].ToString("X2") + " ";

rtfDumpResult.Text += "\r\n";
}

-- modified at 9:24 Monday 2nd July, 2007

Luc Pattyn2-Jul-07 3:25

2-Jul-07 3:25

So my best guess is you dont (always) execute the line rtfDispData.text = "";

you could put it right in front of your nested for loops...

I also noticed your RTB changed names ?

Smile | :)

Luc Pattyn

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Blubbo2-Jul-07 3:32

2-Jul-07 3:32

The code snippet that I showed is the actual rtb name... The thing is that I want to clear the screen so I can see that the software is processing obtaining and encoding bytes into hex equivalent string and display.

Luc Pattyn2-Jul-07 3:46

2-Jul-07 3:46

Just a guess:

maybe you are doing the rtb.Text="" in some other thread (which is illegal!)
and sometimes it works, sometimes it fails (it should always throw an Exception since
.NET 2.0 unless you set CheckForIllegalCrossThreadCalls=false, which one should never do !!).

If so, read up on Control.InvokeRequired and Invoke.
If not, give it a try with Application.DoEvents() following rtb.Text=""; if that helps,
consider it a hack, and try to move the code following it into asynchronous execution
(a separate thread, or something based on timer ticks).

Smile | :)

Luc Pattyn

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Blubbo2-Jul-07 4:11

2-Jul-07 4:11

THAAAAAARRRRR SHE BLOOOOOWWSSSS!

Thanks for the help! its the Application.DoEvents() DOES help! I've used that before and must've forgotten that! Thanks a heap! Smile | :)

Blubbo2-Jul-07 5:06

2-Jul-07 5:06

umm one more thing...

What do u mean "consider it a hack" in the following quote:

"If not, give it a try with Application.DoEvents() following rtb.Text=""; if that helps,
consider it a hack, and try to move the code following it into asynchronous execution
(a separate thread, or something based on timer ticks)."

Can u clarify that? Thanks! I'm not sure of the meaning of it.

Luc Pattyn2-Jul-07 5:25

2-Jul-07 5:25

GUI design rules include the requirement to be responsive at all times, resulting in a
maximum time any action on the GUI thread is allowed to take (some 10 to 30 msec).
If so, there is no need for DoEvents().

Longer operations should be executed in the background, on a separate thread (or
be chopped into smaller pieces and sequenced somehow, e.g. using timer ticks).

There is a pseudo-solution consisiting of calling DoEvents() once or several times
while inside some long method running on the GUI thread; this allows the GUI to update
itself to some degree, but does not offer full responsiveness, hence it is a hack.

There are other requirements, such as:
lengthy operations should indicate they are running (the bare minimum is a WaitCursor);
lengthy operations should show a decent progress indication (Windows often fails to do
that itself);
lengthy operations should be cancellable.

Of course it is up to the designer how far to carry this; it does influence user's
experience tho.

Smile | :)

Luc Pattyn

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Blubbo2-Jul-07 5:29

2-Jul-07 5:29

Hmm thanks for the informative response. I've learned something new.

sort hashtable

arkiboys2-Jul-07 2:51

arkiboys

2-Jul-07 2:51

Hi,
I have populated a hashtable called CacheHashTableForwards.
This is how the hashtable gets populated:

CacheHashTablesForwards.Add(IndexName, code)
...

Now I would like to sort this data which is inside the Hashtable.

Not sure if this is a good approach but I use an ArrayList to do this as follows:

CacheHashTablesForwardsArraySorted = new ArrayList(CacheHashTablesForwards.Keys)

As you can see, The sorted array does not contains the other column, i.e. code
How can I properly sort using the arraylist.
Thanks

Luc Pattyn2-Jul-07 3:04

2-Jul-07 3:04

Hi,

your ArrayList CacheHashTablesForwardsArraySorted is NOT sorted:
1) the Keys property of a hashtable returns an ICollection containing all the keys, but
MSDN clearly states "The order of the keys in the ICollection is unspecified"
2) giving it a name ending on "Sorted" doesnt do it either.

So you must explicitly sort your ArrayList.
Afterwards, you can enumerate the sorted list, and use the hashtable to look up the
corresponding values.

The alternative is to use a SortedList instead of a HashTable; that one does it all.

Smile | :)

Luc Pattyn

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arkiboys2-Jul-07 4:11

arkiboys

2-Jul-07 4:11

Hello again,
I am now fully using sortedList()
This seems to be what I was looking for.
What is the difference between hashtable and sortedlist apart from the sort please?

Luc Pattyn2-Jul-07 4:21

2-Jul-07 4:21

Well, the MSDN documentation is rather abundant on these. Havent studied it in detail.

Seems like SortedList uses just two arrays (and hence needs frequently copying stuff
to insert/remove items), think of it as a normal List that makes sure it remains sorted
at all times, whatever the cost.

HashTable does not care about sorting, it applies a bag of tricks for maximum
performance: it uses a hashing scheme, and linked lists
so it offers best performance especially for large collections or frequent inserts/removals.

Smile | :)

Luc Pattyn

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how to change this in C# ?

leppie2-Jul-07 3:57

leppie

2-Jul-07 3:57

arkiboys wrote:
CacheHashTablesForwardsArraySorted = new ArrayList(CacheHashTablesForwards.Keys)

Assuming 'IndexName' implements IComparable, then you can simply add:

CacheHashTablesForwardsArraySorted.Sort();

xacc.ide-0.2.0.75 - now with C# 3.5 support and Navigation Bar!

LyBun2-Jul-07 2:34

LyBun

2-Jul-07 2:34

I begin learn C#. in C# do not have keyword ReDim Preserve and I wonder how can I change the code below in to C#.

Dim i() as string
Redim i(0)
i(0)= "abc"
ReDim Preserve i(2)
i(1) = "you are the best"
i(2) = "thanks"

Colin Angus Mackay2-Jul-07 2:48

Colin Angus Mackay

2-Jul-07 2:48

LyBun wrote:
C# do not have keyword ReDim Preserve

So, what does it do?

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* Reading: Developer Day 5

Ready to Give up - Your help will be much appreciated.

My website

Luc Pattyn2-Jul-07 3:08

2-Jul-07 3:08

Hi,

there basically are two approaches:

1.
use an array; when it needs to grow, create a new one and copy the contents
(e.g. using Array.Copy)
Thats what ReDim does behind the scenes.

2.
use a collection, such as an ArrayList or a List. These act like stretchable arrays,
but are a bit slower in accessing their elements.

So to choose one or the other you must balance the add/remove operations against the
read/write operations.

Smile | :)

Luc Pattyn

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Martin#2-Jul-07 3:19

Martin#

2-Jul-07 3:19

Hello Luc,

For strings I like to use the dynamic:
System.Collections.Specialized.StringCollection dynstringarray = new System.Collections.Specialized.StringCollection();

All the best,

Martin

Luc Pattyn2-Jul-07 3:29

2-Jul-07 3:29

Hi Martin,

I did not know StringCollection.
I created my own StringList back in the 1.x times, and am still using it...
Thanks for the info.

Smile | :)

Luc Pattyn

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Martin#2-Jul-07 3:32

Martin#

2-Jul-07 3:32

Glad I could give you a info!
Doesn't happen so often.

All the best,

Martin

Luc Pattyn2-Jul-07 3:54