C# Discussion Boards - CodeProject

1-Jul-09 2:07

If there already exist some text in textBox, then

restrict user, so user can not delete/modify that text, but can add(append) text in to textBox. How to do this?

Soppose:
"Quick brown fox jumps" (already present in text box)

so, user can only append text, but can't modify previous text.

like:
"Quick brown fox jumps ......(only from here he can enter/append)"

regards.

musefan1-Jul-09 2:12

musefan

1-Jul-09 2:12

Try handling the KeyPreview event and then check for 'delete/backspace' key when the current text is at a certain length (i.e. the length of the text you want to always be present). That might work

Life goes very fast. Tomorrow, today is already yesterday.

Hum Dum1-Jul-09 2:40

1-Jul-09 2:40

musefan wrote:
(i.e. the length of the text you want to always be present). That might work

I also first thought of this, but suppose if user appended some text then its lenght got increased, now he acts smart and jumps back , then he can delete as length is greater(as he adds some text)

Application is on order progress.
Where user has to update its order action/remarks?

I am fetching text from DB to textControl, and user have to update these fields.

So if user once entered some data and updated it, then next time he can only append new data, can't modify previous data.

Any help appreciated....?
Smile | :)

musefan1-Jul-09 2:43

musefan

1-Jul-09 2:43

I knew it would have a flaw somewhere lol

what about on KeyPreview do some check using the caret position of the text box?

So keep the backspace/delete check and also add - if caret < fixed length then don't allow key press to go through

Life goes very fast. Tomorrow, today is already yesterday.

Hum Dum1-Jul-09 2:56

1-Jul-09 2:56

an example would be greatful.

or else i have to run hit and try method on my own Smile | :)

dojohansen1-Jul-09 6:27

1-Jul-09 6:27

Perhaps if you build on musefan's idea but use the Tag property to store the length of the Text when the TextBox has been initialized (i.e. the "uneditable" text has been assigned to it)..? Then you always know the initial length and you can prevent it from being modified.

However, I think a better solution would be to split the UI to reflect that there's a read-only part and the user may add to this. This would make it easier to implement, and imho more logical for the end user as well.

If you do opt for a single TextBox control you may have to handle cut/copy/paste (if you select text and paste, you replace the selection) as well.

OriginalGriff1-Jul-09 2:16

OriginalGriff

1-Jul-09 2:16

Hum Dum wrote:
How to do this?

Manually.
See TextBox.OnChange event, but be aware that this is "odd" behaviour - not what users expect from a text box. Is there no better solution you can apply, such as moving the text to a label so the TextBox is empty?

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Hum Dum1-Jul-09 2:46

1-Jul-09 2:46

OriginalGriff wrote:
moving the text to a label so the TextBox is empty?

This is one solution?
But moving whole text to a label then adding new text?

application like daily/weekly update on a task.
so text is goes on increasing?

also there are 3-4 fields where user has to add its progress,
and moving each on a seprate labe, makes things somewhat unpleasent?

can't there be any better way.....?

just user can't modify previous data?

any help appreciated....
Smile | :)

OriginalGriff1-Jul-09 3:46

OriginalGriff

1-Jul-09 3:46

Hum Dum wrote:
But moving whole text to a label then adding new text?

application like daily/weekly update on a task.
so text is goes on increasing?

also there are 3-4 fields where user has to add its progress,
and moving each on a seprate labe, makes things somewhat unpleasent?

can't there be any better way.....?

just user can't modify previous data?

any help appreciated....

Ok, so what it is is an update of a to-do-list or similar, with the user inputing new progress?
In which case, yes it will keep increasing - what you need to do is treat each new progress update as a new record and display it in - for example - a grid control. Or better a DataGrid if you store the updates in a database, which would make sense.

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K03061-Jul-09 2:19

K0306

1-Jul-09 2:19

Try this in TextBox Keypress event

if(textbox1.text.lenght > 0)
{
if(e.KeyChar == "backspace","Delete","shift","Home","End"
{
e.Handled = true;
}
}

Luc Pattyn1-Jul-09 2:35

Luc Pattyn

1-Jul-09 2:35

I think that is not sufficient, the user could still use the mouse to select some text, then type new text replacing the selection.

Smile | :)

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DISCLAIMER: this message may have been modified by others; it may no longer reflect what I intended, and may contain bad advice; use at your own risk and with extreme care.

Hum Dum1-Jul-09 2:52

1-Jul-09 2:52

Luc Pattyn wrote:
I think that is not sufficient, the user could still use the mouse to select some text, then type new text replacing the selection.

Yup

Application is on order progress.
Where user has to update its order action/remarks?

I am fetching text from DB to textControl, and user have to update these fields.

So if user once entered some data and updated it, then next time he can only append new data, can't modify previous data.

Luc i am seeing your replies and help from long time on this forum Smile | :)

Is there way to achieve this?

regards Smile | :)

musefan1-Jul-09 3:06

musefan

1-Jul-09 3:06

how about each 'update' is a new entry in the database. then you use a control such as a datagridview (or make a custom one) that displays each entry along with the time and date that it was made. Much better solution

Life goes very fast. Tomorrow, today is already yesterday.

WinApp access variables in WebService...?

Luc Pattyn1-Jul-09 3:38

Luc Pattyn

1-Jul-09 3:38

I would avoid having both old data that should not be changed, and new data, that the user wants to add and edit, in a single control.

Maybe have a read-only TextBox showing what is already processed, and a smaller TextBox allowing the entry (with editing) of new data plus a "Enter" button (or act on ENTER key).

And as always, I don't like Textboxes for large amounts of data, so I would prefer a ListBox or DataGridView for old data, and a Textbox (or whatever suits best) for new data.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

DISCLAIMER: this message may have been modified by others; it may no longer reflect what I intended, and may contain bad advice; use at your own risk and with extreme care.

Mtyb1-Jul-09 0:46

Mtyb

1-Jul-09 0:46

Hello,

How can i access public variables in a WebService..using the object that i create in the WinApp?
Is posible to call method at a WebService by sending its paramters by refrence..?

Thanks Smile | :)

SeMartens1-Jul-09 1:28

SeMartens

1-Jul-09 1:28

Well I would say no. Sending by reference will not work, because both 'apps' (winapp and webservice) reside in different memory spaces. The pointer (reference) to a position in memory will be uselesse to the other part...

It's not a bug, it's a feature!

Check out my CodeProject article Permission-by-aspect.

Me in Softwareland.

dojohansen1-Jul-09 1:31

1-Jul-09 1:31

Hi,

You can't access fields in a web service. It would be possible to change the state of the service by calling a web method and then have the service change it's own state in response to it, but in general web services should be stateless so it's basically a bad idea.

It is not possible to send parameters by reference to a web service.

You might want to look into remoting as it seems the things you want to do are the sort of things a web service isn't right for. Web services have one primary advantage over other services: They are more interoperable - it is possible to build clients for the service using many different tools and this in turn means it can be used by a Symbian cellphone or an iPhone or a Windows/Linux/other-based computer.

It is also possible, with WCF, to build a service class and expose it through remoting AND as a web service (as well as other endpoint types). You may want to learn a bit more about the technologies before you go ahead and design the solution to whatever problem you're trying to solve.

Mtyb1-Jul-09 2:10

Mtyb

1-Jul-09 2:10

//Web Service

public class WebServ : WebService
{
     public VirtualDiskHandler WS_m_pHandler;
}

//Windows Application

private VirtualDiskHandler m_pHandler;

WebServ WebS = new WebServ();
m_pHandler = WebS.WS_m_pHandler;        // this does not work..cant see WS_m_pHandler in the object list

How can i do that..?

dojohansen1-Jul-09 4:43

1-Jul-09 4:43

I understood the question. But (a) you should not make a web service stateful, (b) you cannot read the fields of a web service even if you do give it fields.

So, if you absolutely insist on making your service stateful, you have to add a webmethod that a client could call to get the value of the field, like this:

[WebMethod]
public VirtualDiskHandler GetDiskHandler()
{
   return WS_m_pHandler;
}

As said, this is a bad idea. And even if you *still* insist on doing it, it would only work if VirtualDiskHandler is a type the FrameWork is able to put as xml on the wire in a meaningful way. You can't call methods on it as if the object was running on the client.

If you do not understand this explanation you simply need to study what a web service is before you try to design your own. I'm not saying this to be mean, but because I suspect you need to be told so.

J4amieC1-Jul-09 2:45

J4amieC

1-Jul-09 2:45

dojohansen wrote:
It is not possible to send parameters by reference to a web service.

Are you sure?

dojohansen1-Jul-09 4:48

1-Jul-09 4:48

Jeeze. A reference is ultimately a memory address (though managed by the runtime). How could it possibly even have any meaning to "pass by reference" when what you are actually sending to the server is a bloody SOAP message with XML?

J4amieC1-Jul-09 7:06

J4amieC

1-Jul-09 7:06

dojohansen wrote:
How could it possibly even have any meaning to "pass by reference" when what you are actually sending to the server is a bloody SOAP message with XML

Because SOAP defines the necessary communication protocol to allow it to do so, so although not "by reference" using the strict definition you used, to the programmer it very much is (you even use the ref keyword in C# to define such a web method).

dojohansen1-Jul-09 21:26