BusinessObject update on DetailsView - Exception "No parameterlessco nstructor defined for this object"

[bednarz.thomas]

I have the following business Object(s):

public class ParentObject
{
public ParentObject(st ring somestring)
{
...-
}

....

}

public class MyBusinessObjec t : global::ParentO bject
{
public MyBusinessObjec t (string somestring)
: base(somestring )
{
...
}
// some properties and other stuff
}
On a page I have defined a ObjectDataSourc e for MyBusinessObjec t. It
has a select and update method. It has handlers for OnSelected,
OnSelecting, OnCreating, OnUpdating. It has select parameters.

Select works fine, I could work around the 'Parameterless constructor
exception' by doing:

protected void MyBusinessObjec tDS_Creating(ob ject sender,
ObjectDataSourc eEventArgs e)
{
BO_MyBusinessOb ject mbo = new BO_MyBusinessOb ject(somestring );
e.ObjectInstanc e = mbo;
}

This works just fine!

PROBLEM is the update method!

In my <asp:DetailsVie wcontrol I have defined a OnItemUpdating
EventHandler. This gets calls. After that I get the following
exception:

[MissingMethodEx ception: No parameterless constructor defined for this
object.]
System.RuntimeT ypeHandle.Creat eInstance(Runti meType type, Boolean
publicOnly, Boolean noCheck, Boolean& canBeCached,
RuntimeMethodHa ndle& ctor, Boolean& bNeedSecurityCh eck) +0
System.RuntimeT ype.CreateInsta nceSlow(Boolean publicOnly, Boolean
fillCache) +103
System.RuntimeT ype.CreateInsta nceImpl(Boolean publicOnly, Boolean
skipVisibilityC hecks, Boolean fillCache) +268
System.Activato r.CreateInstanc e(Type type, Boolean nonPublic) +66
System.Web.UI.W ebControls.Obje ctDataSourceVie w.BuildDataObje ct(Type
dataObjectType, IDictionary inputParameters ) +39

System.Web.UI.W ebControls.Obje ctDataSourceVie w.ExecuteUpdate (IDictionary
keys, IDictionary values, IDictionary oldValues) +1294
System.Web.UI.D ataSourceView.U pdate(IDictiona ry keys, IDictionary
values, IDictionary oldValues, DataSourceViewO perationCallbac k
callback) +78
System.Web.UI.W ebControls.Deta ilsView.HandleU pdate(String
commandArg, Boolean causesValidatio n) +1152
System.Web.UI.W ebControls.Deta ilsView.HandleE vent(EventArgs e,
Boolean causesValidatio n, String validationGroup ) +440

I also have a Updating handler on my ObjectDataSourc e. BUT THIS
HANDLER GETS NEVER CALLED, IT CRASHES BEFORE!

Any idea, how I can update with a business object, that has
parameterized constructors??? (I need them, otherwise the objects
could be instantiated without being correctly initialized).

Many thanks for your suggestions

Tom

[=?Utf-8?B?YnJ1Y2UgYmFya2Vy?=]

the ObjectDataSourc e Update,Iinsert, and Delete methods create an instance of
the TypeName to perform these actions. the TypeName object can not have any
contructor parametes as there is no way to define them.

you should make a new object (adapter) that hosts the methods, and creates
correct underlying business objects. its you can use the paramter collection
and the Updating... events to create the underlying objects. a bad practice
to put database methods in a buisiness object anyway, as you want seperation
of layers.

-- bruce (sqlwork.com)
"be************ @gmail.com" wrote:

I have the following business Object(s):

public class ParentObject
{
public ParentObject(st ring somestring)
{
...-
}

....

}

public class MyBusinessObjec t : global::ParentO bject
{
public MyBusinessObjec t (string somestring)
: base(somestring )
{
...
}
// some properties and other stuff
}
On a page I have defined a ObjectDataSourc e for MyBusinessObjec t. It
has a select and update method. It has handlers for OnSelected,
OnSelecting, OnCreating, OnUpdating. It has select parameters.

Select works fine, I could work around the 'Parameterless constructor
exception' by doing:

protected void MyBusinessObjec tDS_Creating(ob ject sender,
ObjectDataSourc eEventArgs e)
{
BO_MyBusinessOb ject mbo = new BO_MyBusinessOb ject(somestring );
e.ObjectInstanc e = mbo;
}

This works just fine!

PROBLEM is the update method!

In my <asp:DetailsVie wcontrol I have defined a OnItemUpdating
EventHandler. This gets calls. After that I get the following
exception:

[MissingMethodEx ception: No parameterless constructor defined for this
object.]
System.RuntimeT ypeHandle.Creat eInstance(Runti meType type, Boolean
publicOnly, Boolean noCheck, Boolean& canBeCached,
RuntimeMethodHa ndle& ctor, Boolean& bNeedSecurityCh eck) +0
System.RuntimeT ype.CreateInsta nceSlow(Boolean publicOnly, Boolean
fillCache) +103
System.RuntimeT ype.CreateInsta nceImpl(Boolean publicOnly, Boolean
skipVisibilityC hecks, Boolean fillCache) +268
System.Activato r.CreateInstanc e(Type type, Boolean nonPublic) +66
System.Web.UI.W ebControls.Obje ctDataSourceVie w.BuildDataObje ct(Type
dataObjectType, IDictionary inputParameters ) +39

System.Web.UI.W ebControls.Obje ctDataSourceVie w.ExecuteUpdate (IDictionary
keys, IDictionary values, IDictionary oldValues) +1294
System.Web.UI.D ataSourceView.U pdate(IDictiona ry keys, IDictionary
values, IDictionary oldValues, DataSourceViewO perationCallbac k
callback) +78
System.Web.UI.W ebControls.Deta ilsView.HandleU pdate(String
commandArg, Boolean causesValidatio n) +1152
System.Web.UI.W ebControls.Deta ilsView.HandleE vent(EventArgs e,
Boolean causesValidatio n, String validationGroup ) +440

I also have a Updating handler on my ObjectDataSourc e. BUT THIS
HANDLER GETS NEVER CALLED, IT CRASHES BEFORE!

Any idea, how I can update with a business object, that has
parameterized constructors??? (I need them, otherwise the objects
could be instantiated without being correctly initialized).

Many thanks for your suggestions

Tom

[Thommy]

On 29 Okt., 18:11, bruce barker
<brucebar...@di scussions.micro soft.comwrote:

the ObjectDataSourc e Update,Iinsert, and Delete methods create an instance of
the TypeName to perform these actions. the TypeName object can not have any
contructor parametes as there is no way to define them.

you should make a new object (adapter) that hosts the methods, and creates
correct underlying business objects. its *you can use the paramter collection
and the Updating... events to create the underlying objects. a bad practice
to put database methods in a buisiness object anyway, as you want seperation
of layers.

-- bruce (sqlwork.com)

"bednarz.tho... @gmail.com" wrote:

I have the following business Object(s):

public class ParentObject
{
* *public ParentObject(st ring somestring)
* *{
* * ...-
* *}

* ....

}

public class MyBusinessObjec t : global::ParentO bject
{
* * public MyBusinessObjec t (string somestring)
* * * * : base(somestring )
* * {
* * * * * ...
* * }
* * // some properties and other stuff
}

On a page I have defined a ObjectDataSourc e for MyBusinessObjec t. It
has a select and update method. It has handlers for OnSelected,
OnSelecting, OnCreating, OnUpdating. It has select parameters.

Select works fine, I could work around the 'Parameterless constructor
exception' by doing:

protected void MyBusinessObjec tDS_Creating(ob ject sender,
ObjectDataSourc eEventArgs e)
{
* * * * BO_MyBusinessOb ject mbo = new BO_MyBusinessOb ject(somestring );
* * * * e.ObjectInstanc e = mbo;
}

This works just fine!

PROBLEM is the update method!

In my <asp:DetailsVie wcontrol I have defined a OnItemUpdating
EventHandler. This gets calls. After that I get the following
exception:

[MissingMethodEx ception: No parameterless constructor defined for this
object.]
* *System.Runtime TypeHandle.Crea teInstance(Runt imeType type, Boolean
publicOnly, Boolean noCheck, Boolean& canBeCached,
RuntimeMethodHa ndle& ctor, Boolean& bNeedSecurityCh eck) +0
* *System.Runtime Type.CreateInst anceSlow(Boolea n publicOnly, Boolean
fillCache) +103
* *System.Runtime Type.CreateInst anceImpl(Boolea n publicOnly, Boolean
skipVisibilityC hecks, Boolean fillCache) +268
* *System.Activat or.CreateInstan ce(Type type, Boolean nonPublic) +66
* *System.Web.UI. WebControls.Obj ectDataSourceVi ew.BuildDataObj ect(Type
dataObjectType, IDictionary inputParameters ) +39

System.Web.UI.W ebControls.Obje ctDataSourceVie w.ExecuteUpdate (IDictionary
keys, IDictionary values, IDictionary oldValues) +1294
* *System.Web.UI. DataSourceView. Update(IDiction ary keys, IDictionary
values, IDictionary oldValues, DataSourceViewO perationCallbac k
callback) +78
* *System.Web.UI. WebControls.Det ailsView.Handle Update(String
commandArg, Boolean causesValidatio n) +1152
* *System.Web.UI. WebControls.Det ailsView.Handle Event(EventArgs e,
Boolean causesValidatio n, String validationGroup ) +440

I also have a Updating handler on my ObjectDataSourc e. BUT THIS
HANDLER GETS NEVER CALLED, IT CRASHES BEFORE!

Any idea, how I can update with a business object, that has
parameterized constructors??? (I need them, otherwise the objects
could be instantiated without being correctly initialized).

Many thanks for your suggestions

Tom

Hi Bruce,

Thanks for that feedback. Do you know of any link that shows some
'best practice' when working with Business Objects and ASP.NET? I have
some experience with Java and Application Servers like JBoss, Tomcat,
Geronimo etc. Seems all to be a bit different with MS technology.

Tom