Re: How can I prohibit writing a characters? - C# Discussion Boards

Re: null exception while passing a serial port instance to an object

Luc Pattyn27-Aug-07 14:41

27-Aug-07 14:41

Hi,

SerialPort is a class, hence a reference type.

You can declare SerialPort references as much as you like, and copy them,
and pass them from one object to another; but you can only create SerialPort
instances (i.e. real objects) by using the "new" keyword.

"new" is not present in the code you have shown, if it is not there at all
then anything you try to do to serialPort1 is doomed to fail with a
NullReferenceException.

Also relevant could be the following MSDN remark on SerialPort.Open:
"The best practice for any application is to wait for some amount of time after
calling the Close method before attempting to call the Open method, as the port
may not be closed instantly."

Since they don't specify "some amount of time" this is not very practical;
the better approach may be to open the port only once.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

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Re: null exception while passing a serial port instance to an object

murr00727-Aug-07 15:56

murr007

27-Aug-07 15:56

Luc,

Thank you for the reply. I have tried using new in the following way, with the same error...

1. making a new instance, and passing it by reference
2. making a new instance, and passing it by value
3. making a new instance, and passing it by both ways to another new instance inside of the target class

Any more suggestions? I greatly appreciate your help.

I also noted the MSDN remark and changed the open/close stuff.

Regards,

Chris

Re: null exception while passing a serial port instance to an object

Luc Pattyn27-Aug-07 17:02

Luc Pattyn

27-Aug-07 17:02

murr007 wrote:
Any more suggestions?

Sure, these two: stop wild experiments and:
1. show the code for one of them, preferably the one you consider the most likely
2. buy a book on C# and work your way through it; books tend to teach you stuff
in a logical order, with simple examples.

BTW if you show code, put it inside PRE tags so we can enjoy the indentation.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

How can I prohibit writing a characters?

daavena27-Aug-07 10:51

daavena

27-Aug-07 10:51

Hi all,

I have a small problem with keyboard input. I have a textbox and I would like to prohibit writing characters(only numbers are allowed).

Do you have any ideas?

Thanks.

David

Re: How can I prohibit writing a characters?

Pete O'Hanlon27-Aug-07 11:18

Pete O'Hanlon

27-Aug-07 11:18

Add a Keypress event handler to the textbox, and do this:

if (!char.IsDigit(e.KeyChar))
{
  e.Handled = true;
}

This assumes that the event args is called e.

Deja View - the feeling that you've seen this post before.

Re: How can I prohibit writing a characters?

daavena27-Aug-07 11:35

daavena

27-Aug-07 11:35

It works!!!

e.Handled = true; what that means?

Thank you.

David

Re: How can I prohibit writing a characters?

Yitzchok Dev27-Aug-07 12:56

Yitzchok Dev

27-Aug-07 12:56

It tells the textbox that the key was handled (was taken care of) and no need for the textbox to handled it

Re: How can I prohibit writing a characters?

daavena28-Aug-07 10:28

daavena

28-Aug-07 10:28

Perfect!!

Thank you very much.

David

UTF-8 characters in RichTextBox with SelectedRtf...

Paradox2227-Aug-07 10:00

Paradox22

27-Aug-07 10:00

I've been writing a chat client, which uses an extended RichTextBox as the chat area.

The RichTextBox takes simple XHTML code (including styles) and converts it into Rtf and displays it. This works great for almost everything.

The problem arises when you try to use extended UTF-8 characters, most notably Japanese Hiragana and Katakana, but also things such as the musical Sharp symbol or the interrobang symbol. These are being displayed as question marks in the RichTextBox.

They exist without problems in the input XHTML; and using a standard RichTextBox I am able to display them correctly. The problem arises when I insert them via the translated XHTML.

Does anyone know of a way that I can preserve the characters when converting to Rtf?

IUPnPDeviceFinder

MicealG27-Aug-07 9:53

MicealG

27-Aug-07 9:53

Hey all I have developed an application that makes use of the upnp.dll, but for some reason my application works fine on some computers but there are a select few that it doesn't work on and I get this error message:

System.Runtime.InteropServices.COMException (0x80070422): Creating an instance of the COM component with CLSID {E2085F28-FEB7-404A-B8E7-E659BDEAAA02} from the IClassFactory failed due to the following error: 80070422.
at [ApplicationName].ServerDetection.StartAsyncTypeSearch()

Can anyone shed some light on what is happening I can't seem to pin this error down.

Any help on this will be highly valued.

Freedom is the right to say that 2+2=5 if this is so everything else will follow.

Re: IUPnPDeviceFinder

Mark Churchill27-Aug-07 15:34

Mark Churchill

27-Aug-07 15:34

Have you made sure the upnp.dll is registered when you install your app on the other computers. Try using regsvr32 on your problem machines.

Mark Churchill
Director
Dunn & Churchill

Re: IUPnPDeviceFinder

MicealG28-Aug-07 5:38

MicealG

28-Aug-07 5:38

Thanks for your reply Mark,

I've check and the DLL has definitely been registered on the problem PCs

Having a hard time tracking down this problem Confused | :confused:

Freedom is the right to say that 2+2=5 if this is so everything else will follow.

Advanced Typed Dataset

hamid_m27-Aug-07 9:42

hamid_m

27-Aug-07 9:42

how can i design a custom Typed Dataset? i create new class from System.Data.dataset and add datatable to it, but it doesn't add datatable list in DataMember!!!

<br />
using System;<br />
using System.Collections.Generic;<br />
using System.Text;<br />
using System.Data;<br />
<br />
namespace MultiTier<br />
{<br />
    class MyDataset : System.Data.DataSet<br />
    {<br />
        public MyDataset()<br />
            : base()<br />
        {<br />
            Table1 = new DataTable();<br />
        }<br />
<br />
        private DataTable Table1;<br />
        public DataTable Table1DataTable<br />
        {<br />
            get { return Table1; }<br />
        }<br />
    }<br />
}<br />

Serial Keys. Make trial version. Examples ?

finayev27-Aug-07 9:40

finayev

27-Aug-07 9:40

Hi. Can anyone help me with understanding how to make a trial version of a program, e.g. it works for 10 days and then refuses to work, until user enters a serial key.
Is there an article about how to do that with examples in c# ? By "Examples" i mean pieces of code where the whole mechanism is written. E.g. how to generate keys. How to disalow user to use program for more than 10 days by simply reinstalling it ?

Thanks in advance

Re: Serial Keys. Make trial version. Examples ?

Spacix One27-Aug-07 10:14

Spacix One

27-Aug-07 10:14

Most people do these though their distribution system such as Install Shield which take your applications binary files and wraps it's usage control around it...

I don't have an example of how this is done in C# but the methood would be to set a obscure reg key when it is first run that encodes the date...

Easy to crack though with a tool like "procmon" from sysinternals (you can see the reg key entry and delete or reset it to when it worked)

You could call it to goto the web but that can be spoofed (easy with %systemroot%/system32/etc/host) too...

Install shield isn't the best method, but will be harder to crack than most home made stuff...
as there are tools to "unwrap" install shield from a program...

best way to limit use on a program is have two versions. One with limited functionally, and another that is paid and have the program "track back" with in-program registration to verify the identity of the user. (CPU SN, Volume ID, and WMP user ID are good to build a GUID off of)

Adding "%" at the end of text in a textbox

basi001427-Aug-07 9:22

basi0014

27-Aug-07 9:22

In my win-form, I am binding a textbox to a property, populated through my object. The property returns a number. Let's say 55.5
I want to add a % sign at the end of this 55.5 without changing the decimal or any of the significant figures.
How can i do it?

Here is what i know so far:
In the binding panel in the text property, under the "Format type" menu, there is a "Custom" option. It has Custom format textbox. If we put the % sign in here in a correct way, it will just be added to the end of the value of the property. So far, 0.0% or 0.00% has not worked as it changes the decimal and significant figures.

Any insight will be appreciated.

Re: Adding "%" at the end of text in a textbox

keyboard warrior27-Aug-07 9:24

keyboard warrior

27-Aug-07 9:24

Are you adding this for a wildcard in SQL?

Or do you just want it to "display" with a percentage when they are done with the text box?

Do you want to show a confirmation with a percent sign?

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Completion Deadline: two days before the day after tomorrow

Re: Adding "%" at the end of text in a textbox

basi001427-Aug-07 9:32

basi0014

27-Aug-07 9:32

I just want a "%" sign with the number to identify it as a percentage value.

Re: Adding "%" at the end of text in a textbox

Spacix One27-Aug-07 10:02

Spacix One

27-Aug-07 10:02

Put a label next to the text box that says "%"

Re: Adding "%" at the end of text in a textbox

basi001427-Aug-07 11:12

basi0014

27-Aug-07 11:12

well this way, % would be always displayed even if the values have not come back. If, you have some method based on the form control, then that would be helpful.
Thanks

Re: Adding "%" at the end of text in a textbox

Big Daddy Farang27-Aug-07 13:03

Big Daddy Farang

27-Aug-07 13:03

In your original post you wrote, "The property returns a number. Let's say 55.5" Would it possible to change your property from whatever "number" type it is (double, decimal, etc.) to string type? That way you could control the significant digits and add the '%' character to the end of the string.

BDF

Re: Adding "%" at the end of text in a textbox

Vikram A Punathambekar27-Aug-07 20:47

Vikram A Punathambekar

27-Aug-07 20:47

You want to add a % sign as a suffix to the content of a textbox?

yourTextBox.Text += "%";

Cheers,
Vıkram.

Be yourself, no matter what they say.
- Sting, Englishman in New York.

Re: Adding "%" at the end of text in a textbox

basi001428-Aug-07 4:43

basi0014

28-Aug-07 4:43

Thanks Vikram,

textBox name is txtPVSav
In the textbox property definitions, I added the following after the textbox binding code.
this.txtPVSav.Text += "%";

But the textbox content only displays the numerical value.

Re: Adding "%" at the end of text in a textbox

basi001428-Aug-07 4:57

basi0014

28-Aug-07 4:57

Ok guys,
I just figured this out.
In the binding panel in the text property, under the "Format type" menu, there is a "Custom" option. It has Custom format textbox. Add the 0.00 "%" in the Custom field.
This will append a % sign at the end of the numberical value and you will still be able to use that property as a numerical input to other parts of your program.

Thanks Vikram for initial headway

Request.Form to Array

keyboard warrior27-Aug-07 9:19

keyboard warrior

27-Aug-07 9:19

ArrayList temp = new ArrayList();
foreach (string var in Request.Form)
{
temp.Add(var);
}

This is the code I'm using to pull out the items in my form. However, I cannot seem to get the values of the data entered into the form. I'm just getting the names of all the objects in the form, but I really want the data as well. Am I missing something?

Confused | :confused:

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