editable image property ?

[--== Alain ==--]

Hi,

I would like to have a property of image type.

i've seen on official .NET component that several controls have such
properties.

My component is built under VC++.NET and not under C#, but as codes are
similar and i did not get any help from relative forum, i'm asking here.

So, i do not have any problem with my component except 1 thing.
When an image is already allocated, i can not delete it or destroy the
bundling with the property by replacing "System.Drawing.Bitmap" with
"(none)".
the (none) appears when i directly edit and erase everything (all
characters) from the image property editor.

in my component it's impossible...
i was thinking to convert my type image to a string (to be able to edit
it in property editor) and after to convert it back, but i would be very
surprised if this is the solution.

please, could you advise me ?

thanks a lot,

Alain

 

[Dave Sexton]

Hi Alain,

Assuming you're using VS 2005 add the following to your property (C#):

[DefaultValue(null)]
public Bitmap MyBitmap { get { return bitmap } set { bitmap = value; } }

In the property window you can select the text and press the delete key or you
can right-mouse click and select "Reset".

 

[--== Alain ==--]

here is my code :

#pragma region public Property : ImageSortAscendant
// Allow user to select the image which will be displayed for column
sorted ascendantly

[System::ComponentModel:efaultPropertyAttribute (nullptr)]
property Bitmap^ ImageSortAscendant
{
Bitmap^ get()
{
return m_ImageSortA;
}
void set(System:rawing::Bitmap^ value)
{
m_ImageSortA = value;
}
}
#pragma endregion

but when i try to compile, i have the following error :
...\RAF_ListView.h(177) : error C3115:
'System::ComponentModel:efaultPropertyAttribute': this attribute is
not allowed on 'RAF_ListView::AR_ListView::ImageSortAscendant'

how could it be possible ?
if i understood well, [DefaultValue(null)] was available on .net v1 only.

thanks,

Al.

 

[Dave Sexton]

Hi Alain,

but when i try to compile, i have the following error :
..\RAF_ListView.h(177) : error C3115:
'System::ComponentModel:efaultPropertyAttribute': this attribute is not
allowed on 'RAF_ListView::AR_ListView::ImageSortAscendant'
how could it be possible ?

I searched MSDN for C3115 - I think you are misusing the attribute.

Attribute Usage on MSDN:
http://windowssdk.msdn.microsoft.com/en-us/library/0b34zz73.aspx

Apparently your example is not the correct way to declare public properties so
that they can use managed attributes. In the link I posted above there is no
reference to public properties at all so I'm not sure how you can accomplish
that (although there is mention of attributes on methods, which I believe is
the direction you'll probably need to go)

Your idea that C# is similar enough to C++ and asking your questions in this
newsgroup isn't going to help you solve your problems. You're probably much
better off finding some managed C++ resources and taking some time to read
them.

if i understood well, [DefaultValue(null)] was available on .net v1 only.

DefaultValueAttribute is still alive and well in the 2.0 framework. I use it
all the time.

--
Dave Sexton

here is my code :

#pragma region public Property : ImageSortAscendant
// Allow user to select the image which will be displayed for column sorted
ascendantly

[System::ComponentModel:efaultPropertyAttribute (nullptr)]
property Bitmap^ ImageSortAscendant
{
Bitmap^ get()
{
return m_ImageSortA;
}
void set(System:rawing::Bitmap^ value)
{
m_ImageSortA = value;
}
}
#pragma endregion

but when i try to compile, i have the following error :
..\RAF_ListView.h(177) : error C3115:
'System::ComponentModel:efaultPropertyAttribute': this attribute is not
allowed on 'RAF_ListView::AR_ListView::ImageSortAscendant'

how could it be possible ?
if i understood well, [DefaultValue(null)] was available on .net v1 only.

thanks,

Al.

Hi Alain,

Assuming you're using VS 2005 add the following to your property (C#):

[DefaultValue(null)]
public Bitmap MyBitmap { get { return bitmap } set { bitmap = value; } }

In the property window you can select the text and press the delete key or
you can right-mouse click and select "Reset".