C# Discussion Boards - CodeProject

Re: Result of division not appear in the textbox

Frank Kerrigan30-Nov-07 0:42

30-Nov-07 0:42

<br />
<br />
double valor1,valor2;<br />
double resultado;<br />
<br />
valor1 = (double) txtValor1.Text;<br />
valor2 = (double) txtValor2.Text;<br />
<br />
if (opcDivide.Checked)<br />
{<br />
resultado=valor1/valor2;<br />
txtResultado.Text=Convert.ToString(resultado);<br />
}<br />
<br />
<br />

You code will fall over as soon as some bright spark enters a non number into your texbox, put a validator on it.

Grady Booch: I told Google to their face...what you need is some serious adult supervision. (2007 Turing lecture)

http://www.frankkerrigan.com/[^]

Re: Result of division not appear in the textbox

moon_stick30-Nov-07 1:10

moon_stick

30-Nov-07 1:10

Though this isn't particularly robust code. Better would be to use something like:

double valor1, valor2;<br />
double resultado;<br />
<br />
if (!double.TryParse(txtValor1.Text, valor1))<br />
{<br />
    valor1 = 0;<br />
}<br />
if (!double.TryParse(txtValor2.Text, valor2))<br />
{<br />
    valor2 = 0;<br />
}<br />
<br />
if (opcDivide.Checked)<br />
{<br />
    try<br />
    {<br />
        resultado = valor1/valor2;<br />
        txtResultado.Text = resultado.ToString();<br />
    }<br />
    catch (DivideByZeroException e)<br />
    {<br />
        txtResultado.Text = "Error";<br />
    }<br />
}

HTH

Dave

It definitely isn't definatley

Re: Result of division not appear in the textbox

Luc Pattyn30-Nov-07 1:49

Luc Pattyn

30-Nov-07 1:49

Hi,

two comments:

1.

moon_stick wrote:
if (!double.TryParse(txtValor1.Text, valor1))
{
valor1 = 0;
}

can be simplified to double.TryParse(txtValor1.Text, valor1)
which does exactly the same, given the following from MSDN:

"When this method returns, contains the double-precision floating-point number equivalent to
the s parameter, if the conversion succeeded, or zero if the conversion failed. The conversion
fails if the s parameter is a null reference (Nothing in Visual Basic), is not a number in a
valid format, or represents a number less than MinValue or greater than MaxValue. This
parameter is passed uninitialized."

2.
It would be better to produce some error indication when TryParse fails.
With your code:
- a mistake in valor1 results in zero, which may be confusing
- a mistake in valor2 results in a divide by zero with a misleading error text

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

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Re: Result of division not appear in the textbox

moon_stick30-Nov-07 3:24

moon_stick

30-Nov-07 3:24

Hi Luc,
Of course you're right - I just couldn't be bothered checking the MSDN documentation to see what was returned if the cast failed sp decided to try and cover my bases.

I was treating the code as if it were working on a simple calculator and limited the range of error messages. In any case, I said it was better, not perfect!! Laugh | :laugh:

Dave

It definitely isn't definatley

Re: Result of division not appear in the textbox

PeterRoman30-Nov-07 3:08

PeterRoman

30-Nov-07 3:08

This code is very good and the Dave too. Smile | :)

Thanks.

Linq on Visual 2005

Berlus29-Nov-07 23:39

Berlus

29-Nov-07 23:39

Can I work with linq using visual 2005 ?
Is there any kind of extension ?
Does it also mean that I can use xlinq (linq to xml) ?

Re: Linq on Visual 2005

Colin Angus Mackay30-Nov-07 0:22

Colin Angus Mackay

30-Nov-07 0:22

It may be possible, if you have the .NET Framework 3.5, to use the Linq namespace in Visual Studio 2005, but you will not be able to use the LINQ syntax as they are a part of the C# 3.0 compiler. But since this syntax is just sugar that compiles down to using the appropriate classes then you can probably still use it, it will just not look as pretty.

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Re: Linq on Visual 2005

Pete O'Hanlon30-Nov-07 0:26

Pete O'Hanlon

30-Nov-07 0:26

Linq has been introduced as part of .NET 3.5, which doesn't run in VS2005. I'm afraid you need one of the VS2008 editions. Once you get it, you can use DLinq and XLinq to your hearts content.

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

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Re: Linq on Visual 2005

Frank Kerrigan30-Nov-07 0:36

Frank Kerrigan

30-Nov-07 0:36

You can use LINQ in almost any data source, its the higher level code that uses it not the backend database.

Grady Booch: I told Google to their face...what you need is some serious adult supervision. (2007 Turing lecture)

http://www.frankkerrigan.com/[^]

Creating Website in SharePoint using C#/ASP.NET

md Nazeem29-Nov-07 23:37

md Nazeem

29-Nov-07 23:37

Hi Guys,
I need to create an Application in C#/ASP.NET which can create an Website in SharePoint 2007.
Please send me information regarding this.

thank you

Mohamed Nazeem
Software Engineer
Bangalore

open an Excel file using c#

ramyanaidu29-Nov-07 23:37

ramyanaidu

29-Nov-07 23:37

hai i need to open an excel file when i click on the open button i need to open in visible mode of excel file it means just display the excel file using c#

Re: open an Excel file using c#

NewToAspDotNet30-Nov-07 0:35

NewToAspDotNet

30-Nov-07 0:35

maybe this helps u:
exap = new Microsoft.Office.Interop.Excel.ApplicationClass();
if (exap == null)
{
MessageBox.Show("can't load excel");
System.Windows.Forms.Application.Exit();
}
exap.Visible = true;

"out of memory" exception and resource management

metalion29-Nov-07 23:14

metalion

29-Nov-07 23:14

Hi
I'm developing a tool that manages a lot of bitmaps, and very big ones; at some point it hits the 1gb limit that all windows apps have and it causes an "out of memory" exception.

The out of memory exception is expected due to the amount of bitmaps loaded, no memory leaks nor bad memory management.

I developed a "image server" that loads the images on demand, and if it hits an out of memory exception, it is able to temporarily release least recently used images.

Now, what I would like to do (and I have absolutely no idea on how to do it), is to capture the "out of memory" exception for the whole application, essentially, these are the events I would like to control:

- somewhere in the application an amount of memory is requested
- there's not enough memory and an "out of memory" exception is thrown
- "somehow", trap the exception, and call the image server to free some resources
- retry again the allocation, and if successful, continue executing the app normally.
- if the retry fail, try again to free some more resources (if possible), and if it is not possible, finally throw the "out of memory" exception.

Is this possible? I'm pretty new to C#, but I guess that, since the GC is in charge of managing the memory, trapping the memory allocation exception should have to be done through the GC api, right?

Thanks in advance

Re: "out of memory" exception and resource management

Christian Graus29-Nov-07 23:17

Christian Graus

29-Nov-07 23:17

Are you calling Dispose on your bitmaps when you're done with them ?

Christian Graus - Microsoft MVP - C++

"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 )

Re: "out of memory" exception and resource management

metalion29-Nov-07 23:23

metalion

29-Nov-07 23:23

yes, I'm calling dispose as soon as I don't need them. As I said, the out of memory exception is expected, due to the size of the bitmaps being loaded

Re: "out of memory" exception and resource management

Luc Pattyn30-Nov-07 0:45

Luc Pattyn

30-Nov-07 0:45

Hi,

you may want to read up on the WeakReference class; it allows to hold on to as much data
as possible without ever hitting an out-of-memory situation.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

Re: "out of memory" exception and resource management

metalion30-Nov-07 1:25

metalion

30-Nov-07 1:25

thanks a lot for the WeakReference hint, I've read a bit about it and it looks exactly what I'm looking for!

IDeviceContext OR How to MeasureText out of the Paint Event

C-Scharbe29-Nov-07 23:04

C-Scharbe

29-Nov-07 23:04

Hello,

I'd like to Resize a control that contains any text.
If I use TextRenderer.MeasureText there is always a Padding, also if I use the Flag NoPadding:

Size size = TextRenderer.MeasureText("dddd", this.Font, new Size(Int32.MaxValue, Int32.MaxValue), (TextFormatFlags.NoPadding));

I found out that i need to set a IDeviceContext like that:

private void MyControl_Paint(object sender, PaintEventArgs e)<br />
{<br />
      Size size = TextRenderer.MeasureText(e.Graphics, "dddd", this.Font, new Size(Int32.MaxValue, Int32.MaxValue), (TextFormatFlags.NoPadding));<br />
}

My Problem is:
I dont want to Resize the Control in the Paint-Event, so I guess I need to get somehow the current IDeviceContext, but how?
Or do I use the TextRenderer.MeasureText method in a wrong way?

Thank You for Your Answers!

Re: IDeviceContext OR How to MeasureText out of the Paint Event

C-Scharbe30-Nov-07 1:04

C-Scharbe

30-Nov-07 1:04

Solution:
IDeviceContext deviceContext = this.CreateGraphics();

ARTICLE AT:
Friday, April 28, 2006
Calculating Size of Multi-Line WinForm Label With MeasureText

http://geekswithblogs.net/paulmehner/Default.aspx

Re: IDeviceContext OR How to MeasureText out of the Paint Event

mav.northwind30-Nov-07 21:05

mav.northwind

30-Nov-07 21:05

Don't forget to dispose of the Graphics object you just created.
It's a very common mistake that leads to resource leaks.

Regards,
mav

--
Black holes are the places where God divided by 0...

Impersonation in C#

dhanashree_129-Nov-07 23:02

dhanashree_1

29-Nov-07 23:02

Hi to all

I had written a ASP.NET WEB App for uploading files on to the server running in Win-2003. I am getting Access Denied Error when i try to upload the files when the application is running. The uploaded files should be stored on another server.

What i did is - We have 2 servers both running on the same Win-2003 OS on Server1 i published by Web App and i want to upload the files to Server2 having shared folders which are accessible to only the users(basically user based authentication is permitted) from the Web App i gave the shared folder path and i Impersonated the User using WindowsIdentity, but still i am not able to access my own folder on the drive.

Can anyone help me out in this?????

Avinash Deshpande

Replacing ReportViewer with Internet Explorer

Ramith Sivanarain29-Nov-07 23:02

Ramith Sivanarain

29-Nov-07 23:02

I am new to VS2005 and C# and only involved with desktop programming. I need to email reports to Customers with only IE and Outlook Express. The Pdf file created by exporting from ReportViewer is 1mb. The body of my reports contain tables and line graphs. Confused | :confused:

Is it possible to do away with ReportViewer and create reports that can be Viewed and Emailed directly from the IE browser. If so what technologies would I have to use eg. Webforms. How do I accomplish this. Thanks

RS

External device

Lol2129-Nov-07 23:01

Lol21

29-Nov-07 23:01

Hey! i need to get input from a external device. how do i connect to that device to get the information?

Re: External device

MickCurley29-Nov-07 23:10

MickCurley

29-Nov-07 23:10

What kind of device...Mouse...Scanner...Fridge??

A craft is an enemy if not well learned.

Re: External device

ChandraRam30-Nov-07 1:59

ChandraRam

30-Nov-07 1:59

Lol21 wrote:
Hey! i need to get input from a external device. how do i connect to that device to get the information?

Get the right kind of cable, plug it in (on both ends), and there you go...

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