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Hi,
I have a windows form which is used to config my application settings. It contains a couple of text boxes that are supposed to contain file paths to some other applications which are used by my application. What I would like to do is when the user clicks the okay button (to accept the changes they've made to the settings) I like the form to validate both text boxes to check that they are okay (a simple test to see if the files actually exist). The problem is that I've tried using the validating event on the text boxes but that gets fired when the textbox losses focus (which I don't want), but doesn't get fired when I click the okay button (which I want to have happen). I tried using the validate event on the form itself, but that never seems to get fired. What's the right way to do this? I know I can just validate the boxes in the OnClick event of the okay button, but I'll probably be adding more controls to the form and I don't want to lump all the validation in one place when it seems to make more sense to have the controls deal with their own validation.
Cheers
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Hi to all,
I have a requirement to call methods of an unmanaged ActiveX control (MFC ActiveX 6.0) from C#. The solution is straightforward if my application is GUI based, but my application has no GUI.
Can anyone give me an idea of how to go about this.
Thanks,
Coding is injurious to health!!
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Hi
I have created a windows form and added a number of datasets from the toolbox. Now, the datasets appears next to menues etc. in the bottom of the form's designview.
Is there a way to access these datasets from the code as a collection - i.e. in the same way as it is possible to access the controls of the form using "this.controls"??
In other words: What I'm looking for is something like "this.datasets" or similiar.
Thanks for your help,
Mads
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Not aware of a 'this.datasets'-like collection in C#. Multiple data adapters within a data set may be accessed in fashion similar to a collection. You probably already knew this. If not though, any way to organize the data within a single set?
>>>-----> MikeO
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Unfortunately there is no way to organize the data within a single set. We have several hundred forms in the app. and each form can contain a number of dataobjects.
The dataobjects are about 30 datasets and each dataset contains one special type of table. Since we need to be able to combine the dataobjects in different ways on each form, it's not possible to organize the data within a single set.
Mads
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When developing gui applications with MFC it is customary to create a worker and a Gui thread. Both of these threads will communicate with each other through a message pump. This kind of architecture will provide a more responsive Gui.
Is there a .Net way of accomplishing the same thing. Basically a Gui thread and a Worker thread no more no less.
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Take a look at Control.Invoke().
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Thank you for your response.
I would like to ellaborate some more in regards to my question. I do not really want to replicate the MFC behavior in .net. Before I do that I would like to know if there is a .net technology that will basicall y accomplish the same thing. For example: Remoting, MessageQueue, web services, etc.
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I have many datagrid-like line item cotrols in a winform form, after user comfirm changes, I need to remove those controls and reload them on the form. The user interface now showing the whole process of removing ctls and reloading. I do want user to have a wait cursor and the form freeze for a while until the process is done, any idears on how to accomplish it?
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Use the form's SuspendLayout() and ResumeLayout() methods.
Cheers, Julian
Program Manager, C#
This posting is provided "AS IS" with no warranties, and confers no rights.
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Hi All!
I've few queries regarding MS Word programming in C#. I need to open a word document (fetched from server) to perform few customize tasks in my client (c# based) and pushed back to server. Pls help me to know how to accomplish following stuff
1. Which activex control should be used... Can I use browser plug-in for this.
2. How to open a word document as read only (no editing should be allowed.)
3. How to open a document associating with a particular template (not the global one) if using a browser plug-in.
4. When a user inserts a comment, the user name that appears in the comment should be my application specific not of the Word application. As api supports this but the modified name should not be reflected in MS WORD.
I would really appreciate of any kind of suggestions.
Thanks In Advance
Bimpy
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In C# it is not legal (or compilable) to let execution fall thru from one switch case context to another.
I'm working on a piece of code to do a MouseHook in C#. Becuase it has to deal with win 32 API messages, I of course have a big long switch statement or two.
An example is deciding which button spawned a particular message, based on the message ID.
In good-ol' C/C++ you'd do it something like this:
int button = 0;
switch ( wParam )
{
case WM_LBUTTONDOWN:
case WM_LBUTTONUP:
case WM_LBUTTONDBLCLK:
button = LEFT;
break;
case WM_RBUTTONDOWN:
case WM_RBUTTONUP:
case WM_RBUTTONDBLCLK:
button = RIGHT;
break;
}Well that won't compile in C# and given the nature of a C# switch statement I can see two alternatives.
MouseButton button = MouseButtons.None;
switch ( wParam )
{
case WM_LBUTTONDOWN:
button = MouseButtons.Left;
break;
case WM_LBUTTONUP:
button = MouseButtons.Left;
break;
case WM_LBUTTONDBLCLK:
button = MouseButtons.Left;
break;
case WM_RBUTTONDOWN:
button = MouseButtons.Right;
break;
case WM_RBUTTONUP:
button = MouseButtons.Right;
break;
case WM_RBUTTONDBLCLK:
button = MouseButtons.Right;
break;
}
or something like :
MouseButton button = MouseButtons.None;
switch ( wParam )
{
case WM_LBUTTONDOWN:
goto case WM_LBUTTONDBLCLK;
case WM_LBUTTONUP:
goto case WM_LBUTTONDBLCLK;
case WM_LBUTTONDBLCLK:
button = MouseButtons.Left;
break;
case WM_RBUTTONDOWN:
goto case WM_RBUTTONDBLCLK;
case WM_RBUTTONUP:
goto case WM_RBUTTONDBLCLK;
case WM_RBUTTONDBLCLK:
button = MouseButtons.Right;
break;
}
Realizing that big switch statements are notoriously buggy and difficult to maintain, I'm torn between which flavor is less bad.
We've all, of course, been schooled on the harmfulness of goto, and the poor person who's got to debug that code four years from now is in for headache.
On the other hand, without the goto's, you end up with a lot duplicate code (all the assignment statements in the above exaple), which always raises a red flag for me (especially because of the maintainance issues duplicate code can cause).
Anybody got an opinion on this? I'm leaning towards the non-goto version but am looking for other opinions.
Cheers,
don
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I don't understand. Your example of stacking up case labels does compile in C#. Here's a small example:
Random r = new Random();
switch (r.Next(10)) {
case 1:
Console.WriteLine("It's one");
break;
case 2:
case 3:
case 5:
case 7:
Console.WriteLine("It's prime");
break;
default:
Console.WriteLine("It's composite");
break;
}
Cheers, Julian
Program Manager, C#
This posting is provided "AS IS" with no warranties, and confers no rights.
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I was getting an error when I was setting up a switch block, and on further examination it looks like it was because I failed to include a break in my default case.
Without the break in the last case statement you get something like: "error CS0163: Control cannot fall through from one case label ('case 2:') to another"
However, when I first encountered the error I found this in the C# MSDN reference on the switch statement:
"Unlike the C++ switch statement, C# does not support an explicit fall through from one case label to another. If you want, you can use goto a switch-case, or goto default."
Now I'm confused, because that apparently doesn't mean what I thought it meant.
The way I read the statement from MSDN, plus if you read the help on error number CS0163 (see reference below), it seems to support my original post.
It seems like either the C# help is in error, or the compiler is in error (or I'm just plain missing something).
don
References
Error CS0163:
ms-help://MS.VSCC.2003/MS.MSDNQTR.2003JUL.1033/cscomp/html/vcerrCompilerErrorSC0163.htm
Switch statement help:
ms-help://MS.VSCC.2003/MS.MSDNQTR.2003JUL.1033/csref/html/vclrfTheSwitchStatement.htm
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Ah ha! You're reading the "simplified" pages and I'm not surprised that you found ambiguity. Personally I tend to go to the authoritative source, the C# Language Reference. Here you see that
a switch statement consists of "switch" followed by an expression in parentheses followed by a switch block
a switch block consists of 0 or more switch sections, the whole wrapped in braces
a switch section consists of one or more switch labels followed by a list of statements
a switch label is either "case" followed by a constant expression followed by colon, or "default" followed by colon.
It is the statement list that cannot "fall through." (In fact, it's stated as "the end point of a statement list cannot be reachable," by which it means that you cannot get to the point just after the last statement in the statement list. In other words, the last statement in the list must be a "jump" type statement: break, goto, throw, etc.)
Hence, <phew>, you can have code that lokos like this:
switch (foo) {
case 1:
case 2:
DoSomething();
break;
...
}
As to the error message, I agree that it could be a little misleading, although it does correctly talk about the last switch label in the (possible) list of labels.
Cheers, Julian
Program Manager, C#
This posting is provided "AS IS" with no warranties, and confers no rights.
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And the light comes on!
It does makes sense now (and also renders my original post completely moot).
Thanks for clearing up the ambiguity for me Julian!
don
To summarize
legal:
switch case( foo )
{
case 0:
case 1:
DoIt();
break;
}not-legal:
switch ( foo )
{
case 0:
DoOneThing();
case 1:
DoAnotherThing();
break;
} also not legal:
switch ( foo )
{
case 0:
DoOneThing();
break;
default:
DoAnotherThing();
}
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I found that GDI+ has some features for smoothing (SmoothingMode,TextRenderingHint...). MSVisio2002 also uses GDI+ (I suppose). But graphics in Visio and my GDI+ application looks different. It seems that Visio uses another smoothing mode, do you know which ?
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MS used to have a thing called "Browser Helper Object", supporting IE4 (maybe 5). Is there a newer parllel to this? To be specific, I would like to gather statistics on my browser, such as download time of each object in a web page. Are there events raised by IE handling such questions?
at first stage, I don't mind activating the browser programmtically (I gather that the strongest feature of the Browser Helper was that it attached itself to any instance of the browser )
YD
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Hi All,
Recently I loaded a C# project am writing using VS.Net 2002 all of a sudden the development enviroment closes my project by it self. It repeated several time any time I load the project and start coding.
I've even reinstalled VS.Net 2002 in an XP OS, tried to open the same project from another PC (Win2k Pro) having VS.Net 2002 . Visual studio.Net 2002
still close itself after allowing me to work for a while.
I am waiting for your sugestions or advice on what to do. I don't know wheather it is a bug with Visual Studio 2002.
Thanks
(I've posted the same question on Visaul studion IDE board)
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Mmm...
Some tips, XP, XP Service Packs. something wrong with your version...
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I've being using the Vs.net 2002 for about 8 months now. Apart from that, I've tried it in two different OS (XP and WIN2K Pro service 3). For now am even afriad opening it in any other machine running visual studio. I have scanned for virus. The file is not infested with virus. Or does there exist different version of VS.Net 2002?
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Hi, i'd like to learn C#, any book titles suggestion!?
nevhile.net
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Hi there,
I am learning too.
Programming C# 3rd Edition by O'REILLY is pretty good.
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Wrox: Professional C# 2nd Edition is fantastic!
Mads
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