Yet another Reflection / Interface Question

[rowe_newsgroups]

I know this has to be answered in the archives somewhere, but the
search results are just confusing me more :-(

Anyways, I authored a control library that contains an Interface
definition and then some usercontrols that implement that interface.
In a separate project I want to load the dll and then load the
usercontrols onto tabpages on my form.

I just cannot seem to figure out how to cast the usercontrols into the
interface type so I can access the defined methods.

Here's the interface thats defined only in the dll:

public interface IReadonlyTab
{
void CreateBindings( );
String CaptionText { get;}
String ConnectionStrin g { get;set;}
event RequestTitleCha ngeEventHandler RequestTitleCha nge;
}

And here's the nonworking code that loads the controls:

String path = @"C:\Documen ts and Settings\srowe\ Desktop
\MyTabs.dll";
Assembly assembly = Assembly.LoadFr om(path);
Type[] types = assembly.GetTyp es();
foreach (Type t in types)
{
Type I = t.GetInterface( "MainTabs.IRead onlyTab");
if (I != null)
{
//I want to do something similar to this:
Type.GetType(I) c =
(Type.GetType(I ))Activator.Cre ateInstance(t);
TabPage tp = new TabPage(c.Capti onText); //CaptionText is
an Interface defined property
tp.Controls.Add (c);
this.tabControl 1.TabPages.Add( tp);
}
}

In case you haven't realized I'm new to using reflection, so please be
nice if I'm missing something obvious here.

I really appreciate any advice you experts can give!

Thanks,

Seth Rowe

[Jon Skeet [C# MVP]]

rowe_newsgroups <ro********@yah oo.comwrote:

I know this has to be answered in the archives somewhere, but the
search results are just confusing me more :-(

Anyways, I authored a control library that contains an Interface
definition and then some usercontrols that implement that interface.
In a separate project I want to load the dll and then load the
usercontrols onto tabpages on my form.

I just cannot seem to figure out how to cast the usercontrols into the
interface type so I can access the defined methods.

Just cast it to IReadonlyTab - that's the interface you want to use, so
that's what you cast it to.

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[rowe_newsgroups]

On Feb 16, 1:35 pm, Jon Skeet [C# MVP] <[e-mail] wrote:

rowe_newsgroups <rowe_em...@yah oo.comwrote:

I know this has to be answered in the archives somewhere, but the
search results are just confusing me more :-(

Anyways, I authored a control library that contains an Interface
definition and then some usercontrols that implement that interface.
In a separate project I want to load the dll and then load the
usercontrols onto tabpages on my form.

I just cannot seem to figure out how to cast the usercontrols into the
interface type so I can access the defined methods.

Just cast it to IReadonlyTab - that's the interface you want to use, so
that's what you cast it to.

--
Jon Skeet - <[e-mail] >http://www.pobox.com/~skeet Blog:http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

Thanks for replying Jon you're a great source of knowledge in this
newsgroup.

I'm afraid I'm still a bit confused as to how to cast it to
IReadonlyTab. The interface is only defined in the dll, not in the
calling application, so I can't do a IReadOnlyTab c =
(IReadOnlyTab)A ctivator.Create Instance(t). That's where I am so
confused, how do I "get" the interface so that I can cast to it?

Thanks again,

Seth Rowe

[Ignacio Machin \( .NET/ C# MVP \)]

>
I'm afraid I'm still a bit confused as to how to cast it to
IReadonlyTab. The interface is only defined in the dll, not in the
calling application, so I can't do a IReadOnlyTab c =
(IReadOnlyTab)A ctivator.Create Instance(t). That's where I am so
confused, how do I "get" the interface so that I can cast to it?

If the interface is only defined in the dll and you are not compiling the
dll with the project there is no way you can use it. Usually you compile
your exec. with the interface that all of your controls implement. Take a
look at Jon Skeet's plugin article

If you do not do this you will have to call the methds using reflection,
which is a pain.
--
Ignacio Machin
machin AT laceupsolutions com

[sloan]

Here is some example code:
public static IRateQuoter GetARateQuoter( )
{
//The RateQuoterSetti ngs encapulates the information found in the
App.Config file
//The "Handler" reads the xml ... to create a RateQuoterSetti ngs
instance.
RateQuoterSetti ngs settings =
((RateQuoterSet tings)System.Co nfiguration.Con figurationSetti ngs.GetConfig(C O
NFIG_SECTION_NA ME));
//Now you have a RateQuoterSetti ngs instance.
//use the assembly and class name from the RateQuoterSetti ngs instance.
to dynamically create the object
return CreateInstance( settings.Assemb lyName, settings.ClassN ame ,
settings.Shippi ngCompanyHomeSt ate );

}

private static IRateQuoter CreateInstance( string assemblyName, string
className , string homeState)
{
IRateQuoter returnObject = null;
Assembly assem = Assembly.Load( assemblyName );
if(null != assem)
{
Type objectType = assem.GetType( className , true , true );
//The use of "homeState" is here... to show how the CreateInstance can
have non default constructors.
//Notice the second argument is an array of objects.. the array of
objects ... needs to match one of the contructor-method-signatures
returnObject = (IRateQuoter)Ac tivator.CreateI nstance( objectType , new
object[] {homeState} );

}
return returnObject;

}
Full code download is available at:

http://sholliday.spaces.live.com/blog/

12/1/2005
Understanding the Simple Factory Pattern


"rowe_newsgroup s" <ro********@yah oo.comwrote in message
news:11******** *************@q 2g2000cwa.googl egroups.com...

I know this has to be answered in the archives somewhere, but the
search results are just confusing me more :-(

Anyways, I authored a control library that contains an Interface
definition and then some usercontrols that implement that interface.
In a separate project I want to load the dll and then load the
usercontrols onto tabpages on my form.

I just cannot seem to figure out how to cast the usercontrols into the
interface type so I can access the defined methods.

Here's the interface thats defined only in the dll:

public interface IReadonlyTab
{
void CreateBindings( );
String CaptionText { get;}
String ConnectionStrin g { get;set;}
event RequestTitleCha ngeEventHandler RequestTitleCha nge;
}

And here's the nonworking code that loads the controls:

String path = @"C:\Documen ts and Settings\srowe\ Desktop
\MyTabs.dll";
Assembly assembly = Assembly.LoadFr om(path);
Type[] types = assembly.GetTyp es();
foreach (Type t in types)
{
Type I = t.GetInterface( "MainTabs.IRead onlyTab");
if (I != null)
{
//I want to do something similar to this:
Type.GetType(I) c =
(Type.GetType(I ))Activator.Cre ateInstance(t);
TabPage tp = new TabPage(c.Capti onText); //CaptionText is
an Interface defined property
tp.Controls.Add (c);
this.tabControl 1.TabPages.Add( tp);
}
}

In case you haven't realized I'm new to using reflection, so please be
nice if I'm missing something obvious here.

I really appreciate any advice you experts can give!

Thanks,

Seth Rowe

[rowe_newsgroups]

On Feb 16, 2:17 pm, "Ignacio Machin \( .NET/ C# MVP \)" <machin TA
laceupsolutions .comwrote:

I'm afraid I'm still a bit confused as to how to cast it to
IReadonlyTab. The interface is only defined in the dll, not in the
calling application, so I can't do a IReadOnlyTab c =
(IReadOnlyTab)A ctivator.Create Instance(t). That's where I am so
confused, how do I "get" the interface so that I can cast to it?

If the interface is only defined in the dll and you are not compiling the
dll with the project there is no way you can use it. Usually you compile
your exec. with the interface that all of your controls implement. Take a
look at Jon Skeet's plugin article

If you do not do this you will have to call the methds using reflection,
which is a pain.

--
Ignacio Machin
machin AT laceupsolutions com

Thanks for the response!

Unfortunately, you confirmed my fears - I was just hoping in my
"newness" to reflection I was missing something. I guess I could use
reflection to just call the methods as you suggest, but how do I map
the events and get/set the properties? Sorry, this is really my first
exposure to reflection. Any good links for this?

Thanks,

Seth Rowe

[rowe_newsgroups]

On Feb 16, 2:17 pm, "sloan" <[e-mail] wrote:

Here is some example code:
public static IRateQuoter GetARateQuoter( )
{
//The RateQuoterSetti ngs encapulates the information found in the
App.Config file
//The "Handler" reads the xml ... to create a RateQuoterSetti ngs
instance.
RateQuoterSetti ngs settings =
((RateQuoterSet tings)System.Co nfiguration.Con figurationSetti ngs.GetConfig(C O
NFIG_SECTION_NA ME));
//Now you have a RateQuoterSetti ngs instance.
//use the assembly and class name from the RateQuoterSetti ngs instance.
to dynamically create the object
return CreateInstance( settings.Assemb lyName, settings.ClassN ame ,
settings.Shippi ngCompanyHomeSt ate );

}

private static IRateQuoter CreateInstance( string assemblyName, string
className , string homeState)
{
IRateQuoter returnObject = null;
Assembly assem = Assembly.Load( assemblyName );
if(null != assem)
{
Type objectType = assem.GetType( className , true , true );
//The use of "homeState" is here... to show how the CreateInstance can
have non default constructors.
//Notice the second argument is an array of objects.. the array of
objects ... needs to match one of the contructor-method-signatures
returnObject = (IRateQuoter)Ac tivator.CreateI nstance( objectType , new
object[] {homeState} );

}
return returnObject;

}

Full code download is available at:

http://sholliday.spaces.live.com/blog/

12/1/2005
Understanding the Simple Factory Pattern

"rowe_newsgroup s" <rowe_em...@yah oo.comwrote in message

news:11******** *************@q 2g2000cwa.googl egroups.com...

I know this has to be answered in the archives somewhere, but the
search results are just confusing me more :-(

Anyways, I authored a control library that contains an Interface
definition and then some usercontrols that implement that interface.
In a separate project I want to load the dll and then load the
usercontrols onto tabpages on my form.

I just cannot seem to figure out how to cast the usercontrols into the
interface type so I can access the defined methods.

Here's the interface thats defined only in the dll:

public interface IReadonlyTab
{
void CreateBindings( );
String CaptionText { get;}
String ConnectionStrin g { get;set;}
event RequestTitleCha ngeEventHandler RequestTitleCha nge;
}

And here's the nonworking code that loads the controls:

String path = @"C:\Documen ts and Settings\srowe\ Desktop
\MyTabs.dll";
Assembly assembly = Assembly.LoadFr om(path);
Type[] types = assembly.GetTyp es();
foreach (Type t in types)
{
Type I = t.GetInterface( "MainTabs.IRead onlyTab");
if (I != null)
{
//I want to do something similar to this:
Type.GetType(I) c =
(Type.GetType(I ))Activator.Cre ateInstance(t);
TabPage tp = new TabPage(c.Capti onText); //CaptionText is
an Interface defined property
tp.Controls.Add (c);
this.tabControl 1.TabPages.Add( tp);
}
}

In case you haven't realized I'm new to using reflection, so please be
nice if I'm missing something obvious here.

I really appreciate any advice you experts can give!

Thanks,

Seth Rowe

Thanks for the reply sloan, but I'm afraid I'm not sure how to use
what you are showing me? All I really need is to access the
usercontrol's methods, events, and properties that are defined by an
interface in it's dll.

Could you please elaborate a bit more?

Thanks,

Seth Rowe

[Jon Skeet [C# MVP]]

rowe_newsgroups <ro********@yah oo.comwrote:

Unfortunately, you confirmed my fears - I was just hoping in my
"newness" to reflection I was missing something. I guess I could use
reflection to just call the methods as you suggest, but how do I map
the events and get/set the properties? Sorry, this is really my first
exposure to reflection. Any good links for this?

Events and properties are available in reflection in the same way as
methods - Type.GetPropert y and Type.GetEvent. Look at PropertyInfo and
EventInfo for what you can then do with them.

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[rowe_newsgroups]

On Feb 16, 3:49 pm, Jon Skeet [C# MVP] <[e-mail] wrote:

rowe_newsgroups <rowe_em...@yah oo.comwrote:

Unfortunately, you confirmed my fears - I was just hoping in my
"newness" to reflection I was missing something. I guess I could use
reflection to just call the methods as you suggest, but how do I map
the events and get/set the properties? Sorry, this is really my first
exposure to reflection. Any good links for this?

Events and properties are available in reflection in the same way as
methods - Type.GetPropert y and Type.GetEvent. Look at PropertyInfo and
EventInfo for what you can then do with them.

--
Jon Skeet - <[e-mail] >http://www.pobox.com/~skeet Blog:http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

Thanks! This is going to be a bit more work than I hoped (isn't always
that way?), but this should get me to where I need to be!

Thanks again to everyone,

Seth Rowe