C# design question - C# Discussion Boards

Dave Kreskowiak17-May-04 6:40

17-May-04 6:40

You could Google for 'OCR' algorithms. There is one here[^] on CodeProject.

RageInTheMachine9532
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Why this default Directory?

Adam °Wimsatt17-May-04 5:38

Adam °Wimsatt

17-May-04 5:38

XmlTextReader reader = new XmlTextReader ("faq.xml");

Why is the default directory for this code = c:\winnt\system32? Maybe I'm missing something, but since this code is located inside of a ASP.Net Default.aspx file... shouldn't it default to the web root?

Re: Why this default Directory?

Heath Stewart17-May-04 5:57

Heath Stewart

17-May-04 5:57

No it shouldn't. It has to do with the executable path or the current working directory set by the executable.

To open a file in a virtual directory, you should use the MapPath method, which is available both on the intrinsic Server property of several objects (an instance of HttpServerUtility) or on the Page class itself:

// Inside a method of the path, for example
string path = MapPath("faq.xml");
XmlTextReader reader = null;
try
{
  reader = new XmlTextReader(path);
  // ...
}
finally
{
  if (reader != null) reader.Close();
}

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Re: Why this default Directory?

Adam °Wimsatt17-May-04 6:04

Adam °Wimsatt

17-May-04 6:04

Thanks for the tip. Do you have any suggetions (websites) for a beginners guide to updating XML files in C#?

Re: Why this default Directory?

Heath Stewart17-May-04 6:19

Heath Stewart

17-May-04 6:19

As I always say - read the .NET Framework SDK. Specifically, read the topic, Exploying XML in the .NET Framework[^]. Don't forget to read the class documentation as well, specifically the members in the System.Xml[^] namespace and child namespaces.

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using excel in c# problem

Russell Jones17-May-04 5:37

Russell Jones

17-May-04 5:37

I'm trying to find the top of a cell in excel.

i tried this code in vba:

something = OutputWorksheet.Range("A1","A1").Top

this works fine

the only way i've found of getting c# to do the same is:

float something = (float)Convert.ToDouble( OutputWorksheet.get_Range("A1","A1").Top.ToString())

is this really the way i have to do this cast?

Thanks

Russell

Re: using excel in c# problem

Heath Stewart17-May-04 5:54

Heath Stewart

17-May-04 5:54

Um, why convert to a Double and then cast to a Single (float)? Also, get_Range returns a Range object, from which you can get the Top and just cast that to a float like so:

Range rng = OutputWorksheet.get_Range("A1", "A1");
float top = (foat)rng.Top;

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C# design question

pankajdaga17-May-04 5:01

pankajdaga

17-May-04 5:01

Hi everyone,

I have an application that should support two types of databases (SQL Server and Oracle). What I want to do is create a datalayer that will use SqlConnection or OracleConnection object depending on the database.

In C++ I would have done the following:

template<class ConnectionType>
class DataLayer
{
...
...

ConnectionType * type
}

DataLayer<SqlConnection> m_layer; // for example

How can I achieve the same result in C#?

Thanks,

Sincerely,

Pankaj

Without struggle, there is no progress

Re: C# design question

Heath Stewart17-May-04 5:10

Heath Stewart

17-May-04 5:10

You would use the provider pattern, an abstract class or interface that contains the methods you would invoke. You then use the appropriate implementation (SQL, Oracle, whatever) that you could configure in the application's .config file. We've been using this since .NET 1.0 for our smart client application.

.NET 2.0 will use the provider pattern heavily: for database access, authentication, personalization, and much, much more.

For more information, you should read a couple of recent MSDN articles:

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Re: C# design question

pankajdaga17-May-04 7:32

pankajdaga

17-May-04 7:32

Thanks Heath!

Pankaj

Without struggle, there is no progress

Managing 3 applications at the same time

Diego F.17-May-04 4:55

Diego F.

17-May-04 4:55

Hi. I need 3 applications working at the same time. The first one is a
Pocket PC application, the second is a web service and the third one isn't
done yet. This third app is only to receive messages (maybe a Windows Forms
application or even an ASP.NET one...)

The question is how to send messages to the third application. It should be
the web service when the Pocket PC calls a web method. How could I do that?
Remoting? I only need to send a string, so the easier method Wink | ;-)

Regards,

Diego F.

Re: Managing 3 applications at the same time

Heath Stewart17-May-04 5:06

Heath Stewart

17-May-04 5:06

.NET Remoting is probably the easiest way. The PPC (presumably a .NET CF application) would call the web service method, which calls a remoting method on the third application. It should be tollerant that the third application might not be running, especially if this is an application that must be started by the user (like a desktop application monitor or something).

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Re: Managing 3 applications at the same time

Diego F.17-May-04 5:33

Diego F.

17-May-04 5:33

OK, then I'll try with Remoting. Is there any consideration I should know using Remoting with web services or is just the same way as using Remoting between two console applications?

Regards,

Diego F.

Re: Managing 3 applications at the same time

Heath Stewart17-May-04 5:38

Heath Stewart

17-May-04 5:38

You should be mindful of the service registration type. If you use a singleton - depending how the remoting object is hosted, yours calls may be synchronous while web service methods are not. This will result in synchronous-like method calls to your web service. The lifetime of the remoting object is also a factor. Basically, there's a lot of factors that go into this. If you're not familiar with .NET Remoting, I suggestion a couple of books. I just posted these earlier today, so I'll just refer you to that post[^].

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Combobox

bertcox17-May-04 4:54

bertcox

17-May-04 4:54

Hi,

I have a combobox and now i want that you can see the first item when it's filled. Now it's empty and you can type in the combobox.

Thx!

Re: Combobox

Heath Stewart17-May-04 5:04

Heath Stewart

17-May-04 5:04

You should change the DropDownStyle property to ComboBoxStyle.DropDownList. The default is DropDown and allows you type, where DropDownList doesn't. If you want the user to be able to type in new items, then you should set the SelectedIndex to 0.

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Edit a file

Appelz17-May-04 3:17

Appelz

17-May-04 3:17

Hello,

I have a xml-file where some words are in uppercase. Is it possible to edit the entire file. So everything in the file is in lowercase?

thx in advance

Re: Edit a file

Dave Kreskowiak17-May-04 3:41

Dave Kreskowiak

17-May-04 3:41

Read the entire file into a String, just like any text file, then call the .ToLower method on the String, then write the new file out to a DIFFERENT file. Write it out a different file just to make sure nothing went wrong and you still have the original file to work from.

RageInTheMachine9532

Re: Edit a file

Heath Stewart17-May-04 3:47

Heath Stewart

17-May-04 3:47

While the two previous answers tell you how, I want to stress the "why and why not". If the XML elements and attributes are supposed to be a certain case, you should leave them. XML elements and attributes are case-sensitive. Changing them would cause any processors specific to that schema (like an XSLT or DOM parser) to fail (at least, identifying it as the appropriate doc type).

If this is a file you have created, then you must make sure that any processing is changed to use the lower-case elements and attributes.

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Image Transparent In C#

Anonymous17-May-04 2:44

Anonymous

17-May-04 2:44

hi why output of this code isn't Transparent.

Bitmap b = new Bitmap(100,20);<br />
Graphics g = Graphics.FromImage(b);<br />
g.Clear(Color.Transparent);<br />
g.DrawString("Test",new Font("Tahoma",8),new SolidBrush(Color.Green),0,0);<br />
b.Save("test.gif",System.Drawing.Imaging.ImageFormat.Gif);<br />
Close();<br />

thanks.

Re: Image Transparent In C#

Heath Stewart17-May-04 3:49

Heath Stewart

17-May-04 3:49

A GIF is an index image, so there is no transparent color. There is, however, a color that is masked so that the GIF appears transparent. See the Bitmap.MakeTransparent method. You provide it a color and that image is saved with that color's index marked as the transparent color so it appears transparent when displayed.

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Getting the Attibute on an element XML

Melanius17-May-04 1:27

Melanius

17-May-04 1:27

Hi i am trying to get the value of an attribute displayed, but i can't seem to find the best way to get to it. If the element contains no attributes it returns -1?

XmlDocument document = new XmlDocument();<br />
			document.Load("..\\..\\commands.xml");<br />
<br />
			XmlNodeReader reader = new XmlNodeReader(document);<br />
<br />
			this.Show();<br />
<br />
			while (reader.Read())<br />
			{<br />
				switch (reader.NodeType)<br />
				{<br />
					case XmlNodeType.Element:<br />
						int attributes = reader.AttributeCount;<br />
						cmdOutput.Text += "<" + reader.Name + reader.GetAttribute(attributes) + ">";<br />
						break;<br />
					case XmlNodeType.Text:<br />
						cmdOutput.Text += "\t" + reader.Value + "\r\n";<br />
						break;<br />
					case XmlNodeType.EndElement:<br />
						cmdOutput.Text += "</" + reader.Name + ">\r\n";<br />
						break;<br />
				}<br />
			}

Re: Getting the Attibute on an element XML

Heath Stewart17-May-04 3:54

Heath Stewart

17-May-04 3:54

Why not just have a case for the XmlNodeType.Attribute? Your switch cases will be called appropriately so even if you were to just write-out the attribute, it will happen in between XmlNodeType.Element and XmlNodeType.Text or XmlNodeType.EndElement, if there are any attributes. What you have anyway will not work anyway. AttributeCount - 1 would be the index of the last attribute. Remember that indexes in the .NET FCL are 0-based.

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Slow sorting with XSL

bertcox17-May-04 0:18

bertcox

17-May-04 0:18

Hello,

Is there a way to sort an xml with xslt faster? Right now a file with 15 records takes about 9 seconds. A file with 60 records takes about 15 seconds. I probably won't have more then 60 records but a file with 1000 records takes about 2 minutes. 15 seconds is still a little to long i think, is it possible to make it faster?

Thx in advance

Re: Slow sorting with XSL

Dave Kreskowiak17-May-04 3:39

Dave Kreskowiak

17-May-04 3:39

How is the sorting being done? Through code you wrote or through an for-each order-by?

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