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How is your editor being invoked? Design-time components are required in order to work with the ComponentModel features of .NET. This doesn't mean they're limited to use at design-time (we use them in our runtime application), but the write objects must exist.
For example, the PropertyGrid provides design-time facilities even at runtime, using the ComponentModel. If you are trying to invoke your editor programmatically, you must also provide implementations of the ITypeDescriptorContext, IServiceProvider (that can return an instance of what services you need, like the IWindowsFormsEditorService), etc.
Microsoft MVP, Visual C#
My Articles
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Hi,
I have code that subtracts two variables (type: double). The problem happends when both variables have the same value (should get 0)...
change = grandTotal - totalPayments;
but result is: 1.4210854715202E-14
(found that out with the MessageBox)
It's mucking up my if statement:
if (change > 0)
thanks,
Ron
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doubles are not accurate they will often contain rounding errors.
You should used double.Epsilon to deal with it.
For example code to test equality should do something like this:
if (Math.Abs(testValueA - testValueB) <= double.Epsilon)
{
}
So your if statement could be something like:
if (change > double.Epsilon)
{
}
Does this help?
"You can have everything in life you want if you will just help enough other people get what they want." --Zig Ziglar
The Second EuroCPian Event will be in Brussels on the 4th of September
Can't manage to P/Invoke that Win32 API in .NET? Why not do interop the wiki way!
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Thanks Colin,
I didn't realize that double would be so buggy.
Ron
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myNameIsRon wrote:
I didn't realize that double would be so buggy
Its not buggy - That how double works. As the precision of floating point operations on processors increases the problem will decrease, but it will never go away completely.
"You can have everything in life you want if you will just help enough other people get what they want." --Zig Ziglar
The Second EuroCPian Event will be in Brussels on the 4th of September
Can't manage to P/Invoke that Win32 API in .NET? Why not do interop the wiki way!
My Blog
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Are you working with money (I can guess it from the variables)? So why use Double if you could use Decimal type for money.
Just my 1 cent 
Regards,
Serge (Logic Software, Easy Projects .NET site)
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Hi Serge,
Thanks, I thought that double would be sufficient...
but I guess not! Using decimal fixes the problem  )
Ron
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Hi Ron,
As far as I know, Decimal is the replacement for Currency data type that was in COM before, and it naturally fits in SQL Server's money datatype.
Regards,
Serge (Logic Software, Easy Projects .NET site)
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Dir sir
+. I'm using FAXCOMLib and C#.net for developing an application.
+. In my Application I have send a fax. But when I click button SendFax
I recevice an Error: "The handle is invalid"
What should I do ?
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I was messing around with this code to hide my taskbar
ShowWindow(FindWindow("Shell_TrayWnd", NULL), SW_HIDE);
I think it's C or C++, but I really don't know... anyways to make it work in my C# app I just put in 0, instead of SW_HIDE. I know SW_HIDE is in winuser.h and equals 0, so thats why I put 0...
So, my question... I feel like i'm cheating "hard coding" a 0. I would like to know how to use SW_HIDE and other things such as -- SW_SHOWNORMAL, SW_MAX etc. in winuser.h -- in my C# program the correct way.
/\ |_ E X E GG
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They are usually just int variables , so you can do it like this:
private int SW_HIDE = 0;
Mazy
"One who dives deep gets the pearls,the burning desire for realization brings the goal nearer." - Babuji
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yeah, that's what i'm doing right now...
/\ |_ E X E GG
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You should actually declare them as consts. When it comes down to it, that's all they really are in C/C++ - constants. Since they're pre-proc definitions, they can't be changed by code. The value is actually inserted.
When you declare them as consts, the value is actually used as well. Those values will never change, and using consts is faster.
You can also use enums, which is another common way (but often requires casting to an int or something). The values of the enum are also used in place of a reference (they're value types).
That's just the way it is.
Microsoft MVP, Visual C#
My Articles
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t h a n k s
/\ |_ E X E GG
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Since you cant use C++ .H files in C#, you have to recode the structures and constants you need from the header files into C# code. Just like Mazy showed you...
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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like sorta make a class library out of them?
/\ |_ E X E GG
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You could. Then in that library, you make the function declarations static so you don't have to instantiate the class in order to use the functions.
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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If I insert .wmf file to an RTF file programatically Or simply by 'opening that RTF file and insert picture' way, it works fine. But when I select the image and try to compress or enlarge it, the line width of the image changes. How to avoid that? I want to make the widh of lines FIX.
Please guide
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What do you mean by "lines"? An image - such as a .wmf - takes up a block of space, not lines. When you change the size of the image, the lines above and below it (perhaps beside it as well, if there's any wrapping) will move, too. This is true even in Word unless you change a lot of settings that aren't available in RTF.
If you want to learn about the RTF codes that you could try to fanagle, read the RTF 1.7 Specifications, available for download at http://www.microsoft.com/downloads/details.aspx?FamilyID=e5b8ebc2-6ad6-49f0-8c90-e4f763e3f04f&DisplayLang=en[^].
Microsoft MVP, Visual C#
My Articles
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Thanks for the reply. I am reading RTF 1.8 Specification.
Let me re arrange my words, "Lines" means, lets say I draw a simple line in .wmf file and add that to RTF document. When I open the document and select .wmf image with the help of mouse and enlarge it, the size (width and height) of the rectangle (i.e. wmf image) increases that is acceptable but at the same time the line's width also increases, it becomes fat. Can we not control it at the time of creation of .wmf image?
sorry for messy description
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That's what's supposed to happen. WMF is a vector graphic, meaning, basically, that the instructions to draw shapes is stored, not the shapes themselves. This is so that proportionally the graphic looks the same at any resolution.
Now, there may be a way to draw a rasterized shape (rendered) but I really don't know.
Microsoft MVP, Visual C#
My Articles
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yes you are very correct, all theory I read so far say the same thing about vector graphics and it is also said that .wmf can contain rasterized shapes (like bitmaps ) but nothing is said about how to add bitmaps to .wmf
may be i need to search more.
thanks
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I have three classes A,B & C
A can instantiate B
B can instantiate C
but A cannot instantiate C
How can we do that
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Put B and C in a separate DLL and mark C as 'internal', instead of 'public'.
Other way is making C a protected (or private) class inside the class B.
Yes, even I am blogging now!
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 I give up. Is there an option D?
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