Re: is this coding correct? - C# Discussion Boards

Christian Graus8-May-08 18:02

8-May-08 18:02

Thomas Toh wrote:
i'm doing asp.net with c#.

Then you should probably use the ASP.NET forum. I told you that last time

Thomas Toh wrote:
i need to use VB input box in c# to validate user input

Well, you really can't. This is why I'm telling you to buy a book, you're missing what ASP.NET *is*. The only thing you can run on the client side, is javascript.

Thomas Toh wrote:
but it doesnt seem to work as it says MessageBox.show does not exit in current context.

Yes, it's trying to tell you what I've told you four times now.

Thomas Toh wrote:
and btw this forum doesn't state its not for beginners.

I am always happy to help beginners. It's people who ignore advice and just ask the same things that frustrate me.

So - for the fifth time. ASP.NET means that you can't use the console, or the message box, or any other winforms or other client side construct to show a message to the end user. Your best bet, is to create a new filename on the server, or to create a new folder to put the same file in. Or, just store it in a DB, where the names can overlap, so long as there's some other way to identify them.

Why are you saving an image in the first place ?

Christian Graus

Please read this if you don't understand the answer I've given you

"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 )

Roger Alsing8-May-08 18:56

Roger Alsing

8-May-08 18:56

Are you sure? Wink | ;-)

*hides*

My Blog

vytheese8-May-08 18:04

vytheese

8-May-08 18:04

Hey I think you complicating the things much. There are out of the box validation controls avialable for the Asp.NET controls. Can you justify why you want to use VB controls ?.

Thomas Toh wrote:
but it doesnt seem to work as it says MessageBox.show does not exit in current context.

MessageBox.Show works in win forms not in asp.net. To achieve the same you can use javascript.

And also forum is not only for throwing a instant answer for the moment, its also guides one to look further on the topics you posted.. So on that sense he told you to buy a book and its also a way of teaching too. Its worth to read a book on starting stage.

Regards,
Vythees

Miles to go before sleep...

Christian Graus8-May-08 19:16

8-May-08 19:16

His issue is, he doesn't know the file already exists until his postback has occured.

I've never seen anyone try to output a prompt in a website on the console before tho.

Thomas Toh8-May-08 18:10

8-May-08 18:10

ok finally thanks for ur constructive response......... so it's possible to use javascript on asp.net for that?

im doing a simple website that allows users to upload image (simply copy/paste image from other folders to my application/images folder). also additional functions.. one of them is to validate whether the image i'm going to upload already existed.. if yes, ask user for input yes/no, if yes overwrite, if no, change a new filename.

i downloaded the sourcecode from here
http://www.codeproject.com/KB/aspnet/netimageupload.aspx also from there modify. atm im stuck at this function... later i'll have to do a Search function on the webpage. that is to search via descriptions/properties of the image not just the filename and i'm not allowed to use DB for that (tho its quite easier right)?

Christian Graus8-May-08 18:38

8-May-08 18:38

If you actually replied to my posts instead of yours, I'd get an email, and the threading on the forums would make sense.

Thomas Toh wrote:
so it's possible to use javascript on asp.net for that?

Kind of. You can show prompts using javascript. However, once you've done a postback, your chance for javascript validation is over, I'd just show a message saying the filename already exists in a control on the page, asking them to rename it and reupload. That is, if you need to do that, overall, I'd take one of the other approaches I suggested ( rename it, put it in a DB, etc )

Thomas Toh wrote:
that is to search via descriptions/properties of the image not just the filename and i'm not allowed to use DB for that (tho its quite easier right)?

You're actually doing a paid project here ? Why can't you use a DB ?

Thomas Toh8-May-08 19:15

8-May-08 19:15

thanks but i don't quite understand your sentence
"However, once you've done a postback, your chance for javascript validation is over"

it's a school project.. no idea as teacher said DB is unnecessary..is there any other way? i've done a simple but not yet complete code lol...

                if (System.IO.File.Exists(Server.MapPath(sSavePath + sFilename)))<br />
                {<br />
                    Response.Write("<script type=\"text/javascript\">var result = confirm('Image already existed. Click OK to overwrite. Click NO for new filename.')</script>");<br />
<br />
                   <br />
                }

Christian Graus8-May-08 19:20

8-May-08 19:20

Thomas Toh wrote:
as i said i'm not allowed to use DB....

But why not ?

Thomas Toh wrote:
Response.Write("var result = confirm('Image already existed. Click OK to overwrite. Click NO for new filename.')");

You're on the right track, but, your page will reload, then your file upload control is empty, and your message box pops up. You will need to do another postback, after the user selects the file again, to get anotehr shot at it. You could use AJAX, but even then, you can't access file paths from javascript. So, your only option as far as I can see, is to find a way to rename the files, or to store the files in folders so the names don't clash. For example, you could store it to a temp filename, store that name in the viewstate, then postback and ask for a new name or if you should overright, but you are better to ask that in the page, not with a popup.

Why can't you use a DB ? You're working on a photo site that needs to be searchable, but can't have a database ? For school, or for a client ?

Thomas Toh8-May-08 19:51

8-May-08 19:51

i'm not sure whether the teacher is dumb or what lol. personally i think DB is so much easier and i have no idea why she said it's unnecessary not needed.

well, i guess i'd have to follow your path lol.i rougly know your idea.. is there a website guide that you could show me so that I can follow the guide?

Christian Graus8-May-08 19:52

8-May-08 19:52

OK - well, your only other option is to store the text in something like an XML file that you maintain. A DB would definately be easier.

Thomas Toh8-May-08 19:58

8-May-08 19:58

yes

i store those image descriptions to a HTML

                // Save the stream to disk<br />
                System.IO.FileStream newFile = new System.IO.FileStream(Server.MapPath(sSavePath + sFilename), System.IO.FileMode.Create);<br />
                newFile.Write(myData, 0, myData.Length);<br />
                newFile.Close();<br />
                TextWriter tw = new StreamWriter(Server.MapPath("Images/Saved Images/" + sFilename + ".html"));<br />
<br />
                // write a line of text to the files<br />
                tw.WriteLine("<html>");<br />
                tw.WriteLine("<img src=\"" + sSavePath + sFilename + "\">" + " " + "<desc=\"" + desc.Text + "\">" + " " + "<mat=\"" + materials.Text + "\">" + " " + "<date=\"" + date.Text + "\">");<br />
                tw.WriteLine("</html>");<br />
<br />
                // close the stream<br />
                tw.Close();

right now i have to solve this function... and next is the toughest part since not using DB.. which is the Searching Smile | :)

Christian Graus8-May-08 20:02

8-May-08 20:02

Well, that's not much use. A single XML file with all your metadata is the most sensible way to do non DB search.

Thomas Toh8-May-08 20:10

8-May-08 20:10

ok i got you... a single XML with all my metadata.. but i remember teacher mentioning about each image file -> each html .. nevertheless, is there any keyword i shld search online for any guide or maybe u could provide some...?

Christian Graus8-May-08 20:26

Search/Parse/Display HTML Metadata

8-May-08 20:26

I would expect that having a single XML file with the file path as the key to storing/updating data would be best. The XmlDocument class is the way to parse XML and XPath is the language you use to do that. If you have a bunch of HTML files, then you can load those as XML, if it's XHTML, but how do you write the code to search ? Sounds messy. A single file with all the metadata, which you can then search, seems best, although it's a long way away from the ease of doing it with a database.

Thomas Toh14-May-08 18:31

14-May-08 18:31

hi,

sorry to post again lol.

is there a basic code sample or guide for html search/parse/display?

on this search.aspx.. i have to do a search function whereby it'll search/parse my HTML files and look inside their's metadata for eg <desc> and then display a link to the HTML file.

my html basically looks like:

ImageFilename.html

Little Help

nelsonpaixao8-May-08 15:53

nelsonpaixao

8-May-08 15:53

Hi, the following code is about getting the right thread to run something left stoped before.
No need help here

private void AppendToRichEditControl(string msg)
{
if (InvokeRequired)
{
object[] pList = {msg}; // this line here
richTextBoxReceivedMsg.BeginInvoke(new UpdateRichEditCallback(OnUpdateRichEdit), pList);
}
else
{
OnUpdateRichEdit(msg);
}
}

private void OnUpdateRichEdit(string msg)
{
richTextBoxReceivedMsg.AppendText(msg);
}

What i want to now is why the use of the {}? why not ()? its wierd. Confused | :confused:

Re: Little Help

Christian Graus8-May-08 15:57

beginner question: how to add method to a class using wizard in VC#2008?

8-May-08 15:57

Because {} is the syntax for creating an array. IF you had more than one element it may be more clear

object[] pList = {msg, msg2, new object()}; // creates an array with three elements

Re: Little Help

MarkB7778-May-08 18:05

MarkB777

8-May-08 18:05

nelsonpaixao wrote:
What i want to now is why the use of the {}? why not ()? its wierd.

Consider the code below:

<br />
int[] numbers = new int[] {1, 2, 3, 4, 5};<br />

This would initalise an array of 5 data locations (i.e int[4]).

The values would be set to the following:

numbers[0] = 1
numbers[1] = 2
numbers[2] = 3
numbers[3] = 4
numbers[4] = 5

Mark Brock

Click here to view my blog

sharp_k8-May-08 14:52

sharp_k

8-May-08 14:52

The documents says right click on class in 'class view' and click on 'add > method'. I do not see this option.
Thanks

Re: beginner question: how to add method to a class using wizard in VC#2008?

Christian Graus8-May-08 15:56