Re: Controls created in one thread cannot parent in other thread - delegate. - C# Discussion Boards

Re: How to get screen area

J. Dunlap13-May-03 18:17

J. Dunlap

13-May-03 18:17

Thanks, although that Poke tongue | ;-P

wasn't necessary. Wink | ;)

"Do unto others as you would have them do unto you." - Jesus

"An eye for an eye only makes the whole world blind." - Mahatma Gandhi

Find the namespace an object is from?

FruitBatInShades13-May-03 8:43

FruitBatInShades

13-May-03 8:43

Does anybody have a code snippet that shows how to find the namespace an object lives in?

Dim obj As Object<br />
Namespace = FindNamespace(Obj)

Re: Find the namespace an object is from?

leppie13-May-03 9:05

leppie

13-May-03 9:05

obj.GetType().Namespace or typeof(Object).Namespace

Hey leppie! Your "proof" seems brilliant and absurd at the same time. - Vikram Punathambekar 28 Apr '03

Re: Find the namespace an object is from?

FruitBatInShades13-May-03 9:28

FruitBatInShades

13-May-03 9:28

Thanks leppie Laugh | :laugh:

Controls created in one thread cannot parent in other thread - delegate.

Mrso13-May-03 5:37

Mrso

13-May-03 5:37

I have a Form that react to a delegate callback and create child controls according to the delegate event argument. But when I try to create the controls and set the parent to the Form at runtime, the subjected exception raised. Any solution on this?

e.g.
Class CA : System.Windows.Forms.Form
{
public CA()
{
CB b = new CB();
b.MyEvent += new OnMyEventHandler( this.OnMyEvent );
}
protected void OnMyEvent( int nCount )
{
for ( int i = 0; i < nCount; i ++ )
{
Button btn = new Button();
btn.Parent = this; <----- Exception
btn.Location = new Point( 100 + i * 100, 10 );
btn.Show();
}
}
}

public delegate void OnMyEventHandler( int nCount );
Class CB
{
public event OnMyEventHandler myEvent;
public CB
{
if ( myEvent != null )
myEvent( 5 );
}
}

Thanks!

Re: Controls created in one thread cannot parent in other thread - delegate.

leppie13-May-03 9:07

leppie

13-May-03 9:07

if (control.InvokeRequired)
  control.Invoke(...., .....);
else
  //call function normally

Hey leppie! Your "proof" seems brilliant and absurd at the same time. - Vikram Punathambekar 28 Apr '03

Re: Controls created in one thread cannot parent in other thread - delegate.

Mrso14-May-03 4:19

Mrso

14-May-03 4:19

Thanks for the hint. But I still have some further question.
The Invoke require a delegate as the arguement. What I want to ask is, if I dynamically create a number of buttons when a delegate callback triggered, can I set those buttons' parent to the original form?

Re: Controls created in one thread cannot parent in other thread - delegate.

Richard Deeming14-May-03 5:35

Richard Deeming

14-May-03 5:35

The simplest solution is to marshal to call to the correct thread when the delegate is invoked:

class CA : System.Windows.Forms.Form
{
    ...
    
    protected void OnMyEvent(int nCount)
    {
        if (this.InvokeRequired)
        {
            // Marshal the call to the correct thread:
            this.Invoke(new OnMyEventHandler(this.OnMyEvent));
        }
        else
        {
            for ( int i = 0; i < nCount; i ++ )
            {
                Button btn = new Button();
                btn.Parent = this; 
                btn.Location = new Point( 100 + i * 100, 10 );
                btn.Show();
            }
        }
    }
}

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

adding form to a panel

zuhx13-May-03 5:30

zuhx

13-May-03 5:30

Hi, I am new to C# and this message board, so I would appreciate any help I can get. I am writing and MDI application, where I have the parent screen split in two areas (with size of the area on the left about 20% of the MDI parent). The area on the left will be the navigation screen and on the right will display the window that results from user action taken on the left. I am trying to get the windows on the right to display the maximum size of its alloted area and I thought I can do this by adding it to a panel. Is it possible to add a form to a panel and if so can any provide some code on doing this. If not, is there some kind of container to restrict the child form size to its alloted area. Thanks.

[Announce] diagnosing interop marshaling

Stephane Rodriguez.13-May-03 5:15

Stephane Rodriguez.

13-May-03 5:15

Someone who wrote a book[^] about .NET interop has released a free tool[^] to monitor type marshaling inside the CLR. It takes advantage of .NET 1.1. It works on all machines, although Windows XP is required to show the balloon tooltips.

Re: [Announce] diagnosing interop marshaling

David Stone13-May-03 5:23

David Stone

13-May-03 5:23

Clicking on the second link gives you a "Server error in / application."

Hawaian shirts and shorts work too in Summer.
People assume you're either a complete nut (in which case not a worthy target) or so damn good you don't need to worry about camouflage...
-Anna-Jayne Metcalfe on Paintballing

Re: [Announce] diagnosing interop marshaling

Kant13-May-03 6:15

Kant

13-May-03 6:15

The tool link works for me.

For others if you don't know about Adam Nathan, he is CLR Test Lead.

Don't Beer | [beer]

and drive.

Re: [Announce] diagnosing interop marshaling

David Stone13-May-03 7:54

David Stone

13-May-03 7:54

Kant wrote:
For others if you don't know about Adam Nathan, he is CLR Test Lead.

And a freaking god when it comes to Interop.

Re: [Announce] diagnosing interop marshaling

Kant13-May-03 8:11

Kant

13-May-03 8:11

I bet he is Stephane's guru. Wink | ;)

Don't

and drive.

Re: [Announce] diagnosing interop marshaling

Stephane Rodriguez.13-May-03 9:08

Stephane Rodriguez.

13-May-03 9:08

eh... who knows Wink | ;)

Re: [Announce] diagnosing interop marshaling

Richard Deeming14-May-03 5:40

Richard Deeming

14-May-03 5:40

Don't forget to read his blog[^] as well. Apparently, the new Application.EnableVisualStyles() method has a marshalling bug in it. Roll eyes | :rolleyes:

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

Re: [Announce] diagnosing interop marshaling

Stephane Rodriguez.14-May-03 6:55

Stephane Rodriguez.

14-May-03 6:55

I am subscribed to it since day one. But quite honestly, I think I am gonna quit it altogether as I tend to think that as a "customer" I don't have to learn the intrinsics of an engine whose implementation is going to change anyway.
For any current problem, the work around is to write a dll and use a P/Invoke native call to bypass the CLR itself. It only takes an F-grade know-how to do so. I swallow a small raisin, leaving away all this crap.

Setting events - beginner question

Neil Lamka13-May-03 4:57

Neil Lamka

13-May-03 4:57

I'm trying to educate myself on C# and .Net. I decided to try and use the techniques outlined by Marc Clifton ("Using XML to generate Menus") but to use it with a different UI tool kit along with extending the menus.xsd to support imagelists.

What I'm looking for is a method of taking an input name (of an imagelist or a method) passed in the xml definition or the menu and use that name to pass the actual object or method to the appropriate constructors etc.

I've found that I can find the appropriate MethodInfo information using reflection and can find the FieldInfo information for an imagelist but I can't seem to figure out how to use that information to accomplish my objective. I'm using the Crownwood Magic Library menus that have a MenuCommand constructor that will take an imagelist and index value for the menu image and will take an EventHandler for an OnClick event.

Is there a way to use the information retrieved form the reflection methods to set the event handler and to set the imagelist from the names passed in the xml.

Thanks for the help

Neil Lamka
neil@meetingworks.com

Re: Setting events - beginner question

Bo Hunter14-May-03 10:02

Bo Hunter

14-May-03 10:02

I beleave you are on the wright track you just need to use the
typeof( YourType ).GetMethod( "MethodName", BindingFlags.Public ).Invoke( objToCallInvokeOn, new object[](arg1, arg2, arg3} );

The BindingFlags is just that there flags so you can use | operator.
The args can be null new object[]{null} or null will work I beleave.
There are a few different ways and method overloads that is avaliable.

Re: Setting events - beginner question

Neil Lamka14-May-03 11:29

Neil Lamka

14-May-03 11:29

Thanks for the pointer.

If I use this method then I'm assuming that in my DLL that handles reading the XML definitions for menus and all that I'd have

1) Set an "OnClick" event handler internal to my DLL
and then
2) When processing the OnClick event figure out the real target menthod that should process the event and use the Invoke as you described.

Is there any way to set the event handler for the menu item so as to bypass having to handle the event and route it? I'd like to get out of the way and just wire the menu directly to the desired handler. I was hoping that once I found the MethodInfo for the target method I would be able to set the menu event handler directly. Or is that what your note allows me to do and I just did not understand.

Thanks
Neil

Neil Lamka
neil@meetingworks.com

Re: Setting events - beginner question

Bo Hunter16-May-03 19:57

Bo Hunter

16-May-03 19:57

Sorry it took so long to get back. I hate to say it but I dont fully
understand what it is you need to do. Just a little more info on what
you need to do and maybe I can help some more.

Bo Hunter

Re: Setting events - beginner question

Neil Lamka17-May-03 5:30

Neil Lamka

17-May-03 5:30

Ok, Let me try again.

What I'd like to be able to do is (from a class in a managed DLL) to take a method name from a file, create a menu item and set the "OnClick" event to use that method.

What I have been able to figure out is how to set an onclick event handler that resides in my DLL and then to use Invoke to route the event to the desired handler within the application. I was looking for a direct way to wire the event handler to the menu item without the intermediate handling.

I have the MethodInfo for the desired (real) event handler but don't see any way to use that to set the OnClick event using that information.

An example would be something like

<xmlstuff>
<menuitem>
&File
<onclick>My_Handler

....
in the DLL

string caption = ... get the caption from the xml
string onclick = ... get the handler from the xml
MethodInfo mi = ... get the MethodInfo for "My_Handler" (from onclick)
//* I'm using the MagicLibrary .. which is where the MenuCommand lives
MenuCommand mc = new MenuCommand( caption );
mc.Click += ??? using the MethodInfo from above.

What I do have is the above but with

mc.Click += new EventHandler(menu_Click); //menu_Click is my internal handler)

private void menu_Click(object sender, System.EventArgs e)
{
MethodInfo mi = .. get the Method info for the real handler
....
mi.Invoke(_callingInstance, args);
....
}

So..the .Net of what I'm trying to do is to use what I can find out from Reflection to wire a menu item directly to the target event handler without having to use Invoke and this event redirection.

Hope this helps

Neil Lamka
neil@meetingworks.com

Index/Custom Control

Kant13-May-03 4:48

Kant

13-May-03 4:48

1.How to get the index (int) from ImageList.Images?(this returns System.Drawing.Image)

2. Right click on Solution -> Add -> Add New Item. In that dialog, Is the "OPEN" button a custom control? Is it available via Toolbox?

Don't Beer | [beer]

and drive.

changes in a datagrid?

Manster13-May-03 4:26

Manster

13-May-03 4:26

Can anyone help me get my datagrid to update it's data?
I’ve populated a datagrid with the contents of a table from an access database, but the problem I’m running into is when I change a value in the grid it’s not being saved/updated/deleted in the database. Has anyone ever done anything like this before? I've seen some examples in sql server and one or two things in access from the web but none of them seem to work correctly.

Poke tongue | ;-P

Thanks

Re: changes in a datagrid?

Kant13-May-03 4:55

Kant

13-May-03 4:55

Manster wrote:
Can anyone help me get my datagrid to update it's data?

Looks like nobody answered your earlier post. Wink | ;)

Anyway I will try.

Did you check the RowState property "DataRowState.Modified" value?

Don't Beer | [beer]

and drive.

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