Collection Property in web custom control

[Class]

Hi all,

I'm building a custom control. I would like that on the control you can set
some 'rights'
For that I have an enum:
public enum GroupRights

{
Group0 = 0,
Group1 = 1,
Group2 = 2,
Group3 = 3,
Group4 = 4,
Group5 = 5,
}

In design time I want to set these right (can be multiple rights at the same
time)
So I put them in a generic list:

[Category("Rights")]
[DefaultValue("")]
[Localizable(true)]
[Bindable(true)]
public List<GroupRights> ControlRights
{
get
{
List<GroupRights> temp = (List<GroupRights>)ViewState["ControlRights"];
return ((object)temp == null) ? new List<GroupRights>() : temp;
}

set
{
ViewState["ControlRights"] = value;
}}

In desgin time I get the controls window with the GrouRights enum to choose
from.
But when I add one right in the collection window I get the message:

Cannot create an object of type
'System.Collections.Generic.List`1[[GroupRights, MaxControls,
Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]' from its string
representation '(Collection)' for the 'ControlRights' property.

Also the property can not be read out during runtime.

What am I doing wrong or forgetting?

tia,

Class

 

[Michael Tkachev]

Your class must be serializible. Or use Session instead of ViewState.

Sincerely yours,
Michael B. Tkachev.
(e-mail address removed)

 

[Class]

Hi Michael,

Thanks for your response.

Your class must be serializible. Or use Session instead of ViewState.

Which class do you mean, that needs to be serializable?
The enum? or The List class?
The list is a generic .NET collection class which is serializable already,
right?
Session?? There is no Session object in a web custom control, what do you
mean??

Thanks,
Class

Your class must be serializible. Or use Session instead of ViewState.

Sincerely yours,
Michael B. Tkachev.
(e-mail address removed)

Hi all,

I'm building a custom control. I would like that on the control you can
set some 'rights'
For that I have an enum:
public enum GroupRights

{
Group0 = 0,
Group1 = 1,
Group2 = 2,
Group3 = 3,
Group4 = 4,
Group5 = 5,
}

In design time I want to set these right (can be multiple rights at the
same time)
So I put them in a generic list:

[Category("Rights")]
[DefaultValue("")]
[Localizable(true)]
[Bindable(true)]
public List<GroupRights> ControlRights
{
get
{
List<GroupRights> temp = (List<GroupRights>)ViewState["ControlRights"];
return ((object)temp == null) ? new List<GroupRights>() : temp;
}

set
{
ViewState["ControlRights"] = value;
}}

In desgin time I get the controls window with the GrouRights enum to
choose from.
But when I add one right in the collection window I get the message:

Cannot create an object of type
'System.Collections.Generic.List`1[[GroupRights, MaxControls,
Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]' from its string
representation '(Collection)' for the 'ControlRights' property.

Also the property can not be read out during runtime.

What am I doing wrong or forgetting?

tia,

Class

 

[Michael Tkachev]

Take the "Page" property and there you can find Session

Hi Michael,

Thanks for your response.

Your class must be serializible. Or use Session instead of ViewState.

Which class do you mean, that needs to be serializable?
The enum? or The List class?
The list is a generic .NET collection class which is serializable already,
right?
Session?? There is no Session object in a web custom control, what do you
mean??

Thanks,
Class

Your class must be serializible. Or use Session instead of ViewState.

Sincerely yours,
Michael B. Tkachev.
(e-mail address removed)

Hi all,

I'm building a custom control. I would like that on the control you can
set some 'rights'
For that I have an enum:
public enum GroupRights

{
Group0 = 0,
Group1 = 1,
Group2 = 2,
Group3 = 3,
Group4 = 4,
Group5 = 5,
}

In design time I want to set these right (can be multiple rights at the
same time)
So I put them in a generic list:

[Category("Rights")]
[DefaultValue("")]
[Localizable(true)]
[Bindable(true)]
public List<GroupRights> ControlRights
{
get
{
List<GroupRights> temp = (List<GroupRights>)ViewState["ControlRights"];
return ((object)temp == null) ? new List<GroupRights>() : temp;
}

set
{
ViewState["ControlRights"] = value;
}}

In desgin time I get the controls window with the GrouRights enum to
choose from.
But when I add one right in the collection window I get the message:

Cannot create an object of type
'System.Collections.Generic.List`1[[GroupRights, MaxControls,
Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]' from its string
representation '(Collection)' for the 'ControlRights' property.

Also the property can not be read out during runtime.

What am I doing wrong or forgetting?

tia,

Class

 

[Nathaniel Greene]

Whoa, Whoa, Whoa, Whoa.
Remember that a session should only be used to store information when this
information is stored on a "per" user basis. What if you have 30 of these
controls on a single web page and the user is browsing 2 different web pages
at the same time ont he same site under the same session. That's 60 controls
overwriting each other.

Class, what is happening is the fact that you are trying to serialize Enums.
Your first step should be to convert your List<EnumRights> to a enumrights[],
this is done through the .ToArray() method.
Do this when you save your items in the viewstaet. When you load your
viewstaet you can create a new List<EnumRights> by using the
MyEnumRights = new List<EnumRights>((List<Enumrights>) viewstate["bleah"]);

The Constructor overload for a List<> accepts Ienumerable which a type[]
implements so this works. This should solve all of your serialization
problems. Worst case scenario - you may have to, assuming your enums have
values, convert it to an array of integers - but I don't think you have to do
this.

Take the "Page" property and there you can find Session

Hi Michael,

Thanks for your response.

Your class must be serializible. Or use Session instead of ViewState.

Which class do you mean, that needs to be serializable?
The enum? or The List class?
The list is a generic .NET collection class which is serializable already,
right?
Session?? There is no Session object in a web custom control, what do you
mean??

Thanks,
Class

Your class must be serializible. Or use Session instead of ViewState.

Sincerely yours,
Michael B. Tkachev.
(e-mail address removed)

Hi all,

I'm building a custom control. I would like that on the control you can
set some 'rights'
For that I have an enum:
public enum GroupRights

{
Group0 = 0,
Group1 = 1,
Group2 = 2,
Group3 = 3,
Group4 = 4,
Group5 = 5,
}

In design time I want to set these right (can be multiple rights at the
same time)
So I put them in a generic list:

[Category("Rights")]
[DefaultValue("")]
[Localizable(true)]
[Bindable(true)]
public List<GroupRights> ControlRights
{
get
{
List<GroupRights> temp = (List<GroupRights>)ViewState["ControlRights"];
return ((object)temp == null) ? new List<GroupRights>() : temp;
}

set
{
ViewState["ControlRights"] = value;
}}

In desgin time I get the controls window with the GrouRights enum to
choose from.
But when I add one right in the collection window I get the message:

Cannot create an object of type
'System.Collections.Generic.List`1[[GroupRights, MaxControls,
Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]' from its string
representation '(Collection)' for the 'ControlRights' property.

Also the property can not be read out during runtime.

What am I doing wrong or forgetting?

tia,

Class

 

[Class]

Hi Nathaniel,

Thank you for your response.
When I try your suggestion and I try to add a right in the colleciton
Editor:
'Unable to cast object of type
'System.Collections.Generic.List`1[GroupRights]' to type
'System.Collections.Generic.List`1[GroupRights]''

This is the code I have now:
public List<GroupRights> Rights
{
get
{
if (ViewState["Rights"] != null)
{
List<GroupRights> s = new
List<GroupRights>((IEnumerable<GroupRights>)ViewState["Rights"]);
return ((s == null) ? new List<GroupRights>() : s);
}
else
{
return null;
}
}
set
{
if (value != null)
ViewState["Rights"] = value.ToArray();
else
{
List<GroupRights> s = new List<GroupRights>();
s.Add((GroupRights)1);
ViewState["LikMe"] = s;
}
}
}

Regards,
Maarten

Whoa, Whoa, Whoa, Whoa.
Remember that a session should only be used to store information when this
information is stored on a "per" user basis. What if you have 30 of these
controls on a single web page and the user is browsing 2 different web
pages
at the same time ont he same site under the same session. That's 60
controls
overwriting each other.

Class, what is happening is the fact that you are trying to serialize
Enums.
Your first step should be to convert your List<EnumRights> to a
enumrights[],
this is done through the .ToArray() method.
Do this when you save your items in the viewstaet. When you load your
viewstaet you can create a new List<EnumRights> by using the
MyEnumRights = new List<EnumRights>((List<Enumrights>)
viewstate["bleah"]);

The Constructor overload for a List<> accepts Ienumerable which a type[]
implements so this works. This should solve all of your serialization
problems. Worst case scenario - you may have to, assuming your enums have
values, convert it to an array of integers - but I don't think you have to
do
this.

Take the "Page" property and there you can find Session

Hi Michael,

Thanks for your response.

Your class must be serializible. Or use Session instead of ViewState.

Which class do you mean, that needs to be serializable?
The enum? or The List class?
The list is a generic .NET collection class which is serializable
already,
right?
Session?? There is no Session object in a web custom control, what do
you
mean??

Thanks,
Class

Your class must be serializible. Or use Session instead of ViewState.

Sincerely yours,
Michael B. Tkachev.
(e-mail address removed)

Hi all,

I'm building a custom control. I would like that on the control you
can
set some 'rights'
For that I have an enum:
public enum GroupRights

{
Group0 = 0,
Group1 = 1,
Group2 = 2,
Group3 = 3,
Group4 = 4,
Group5 = 5,
}

In design time I want to set these right (can be multiple rights at
the
same time)
So I put them in a generic list:

[Category("Rights")]
[DefaultValue("")]
[Localizable(true)]
[Bindable(true)]
public List<GroupRights> ControlRights
{
get
{
List<GroupRights> temp =
(List<GroupRights>)ViewState["ControlRights"];
return ((object)temp == null) ? new List<GroupRights>() : temp;
}

set
{
ViewState["ControlRights"] = value;
}}

In desgin time I get the controls window with the GrouRights enum to
choose from.
But when I add one right in the collection window I get the message:

Cannot create an object of type
'System.Collections.Generic.List`1[[GroupRights, MaxControls,
Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]' from its
string
representation '(Collection)' for the 'ControlRights' property.

Also the property can not be read out during runtime.

What am I doing wrong or forgetting?

tia,

Class