Visual Basic

Re: Open a program with a function initiated

3-Jul-06 5:05

No, there is no way to do this. If the app you're launching doesn't support opening certain items on launch, then you can't do it, period. This kind of functionality, also, doesn't have any standards defined for it, outside of DDE, so it's implementation would be entirely up to the application your trying to launch, if it supports it at all!

The only other method, though unreliable, would be to use SendKeys to try(!!!) to send the appropriate key strokes to the application you launched to get the functionality you want. The problem is that you have to launch the app, then wait, somehow, for the app to finish loading, then send the keystrokes. Also, between the time the app is launched and the keystrokes are sent, pray that the user doesn't hit any keys and doesn't click on anything with the mouse. Oh! Since Windows is a shared system, you also have to hope that no other application running in the system steals the input focus during that time too!

Dave Kreskowiak
Microsoft MVP - Visual Basic

szevy_suez4-Jul-06 7:24

szevy_suez

4-Jul-06 7:24

Thanks

Open another program/software [modified]

szevy_suez3-Jul-06 4:03

szevy_suez

3-Jul-06 4:03

Hi,
Do anyone of u know how to open another program/software from a vb.net project? For example, if the user click a certain button, it will cause a program(paint, for example) to open. Is it possible to do that?

-- modified at 10:53 Monday 3rd July, 2006

Re: initialise another program/software

Duncan Edwards Jones3-Jul-06 4:16

Duncan Edwards Jones

3-Jul-06 4:16

System.Diagnostics.process.Start("paint.exe")

'--8<------------------------
Ex Datis:
Duncan Jones
Merrion Computing Ltd

Re: initialise another program/software

szevy_suez4-Jul-06 7:25

szevy_suez

4-Jul-06 7:25

Thanks

Datagrid style

microuser_20003-Jul-06 2:48

microuser_2000

3-Jul-06 2:48

hellow to all
i had created a DataGridTableStyle , and DataGridTextBoxColumn , now i wanna to access the datagrid and get information about the width of every coloum in the datagrid , i had worte this line of code
(grdWorkMaps.TableStyles("ts").GridColumnStyles.Item("cs28").Width.ToString)
but it is not working for me .
anyone have anyidea ?
thxx

Unloading AppDomain [modified]

matsnas3-Jul-06 1:37

Re: Unloading AppDomain [modified]

3-Jul-06 1:37

Newbi to the whole appdomain-ting but my understanding was that it is a controllable area of a process where I can load code where I can enforce security and at any time unload it.

I want to use it to extend my applications functionallity and at any time given a specific term can unload from memory and eventually restart. This way I could have memory intense parts loaded when I need them instead of all the time.

However I don't get this to work but I'm probably doing some beginners error?1

My code goes something like this:

AppDomainClient<br />
 - Plugin.vb (class implementing AppDomainInterfaces.IPlugin)<br />
<br />
AppDomainInterfaces<br />
 - IPlugin.vb<br />
 - IPluginFactory (Inherits MarshalByRefObject)<br />
<br />
AppDomainApplication<br />
 - MainForm.vb

I start the MainForm by creating an AppDomain. The appdomain object is passed to an instace of the IPluginFactory and used to CreateInstanceAndUnwrap an instance of the Plugin class. The Plugin class is returned as the IPlugin interface to the MainForm. In the constructor of the Plugin class a method EatMemory is called which allocates a very big string. This workes fine and the memory allocated by the application goes through the roof!

When I try to unload the AppDomain I don't get any errors but the memory is still occupied with the same number of bytes as before I ran the unload command:
AppDomain.Unload("MyCustomAppDomain") I was expecting it to decrease mack to what I had before I loaded the Plugin?

-- modified at 7:37 Monday 3rd July, 2006

Dave Kreskowiak3-Jul-06 7:41

3-Jul-06 7:41

matsnas wrote:
When I try to unload the AppDomain I don't get any errors but the memory is still occupied with the same number of bytes as before I ran the unload command:

Did you determine this using the TaskManager or using the Performance Monitor or a Memory Profiler? If you used TaskManager, you picked possibly the worst tool you could use for checking the memory use of your app. TaskManager will show you the memory use of the entire virtual machine your app is running in (the .NET Common Language Runtime). This includes memory that the CLR has reserved for your app, but not in actual use by your application...

Dave Kreskowiak
Microsoft MVP - Visual Basic

-- modified at 13:42 Monday 3rd July, 2006

matsnas3-Jul-06 8:40

3-Jul-06 8:40

Well actually I did but only because I didn't get the Performance Monitor working in a good way. Anyway I also tried to have my plugin display a WinForm in it constructor believing that it would go away when my plugin's appdomain was unloaded but it didn't.

I'm missing some vital part of understanding here I think. All documentation refer to the current AppDomain beeing "unloaded" but what do they actually mean by unloaded? Valid for unloading when the GC feels like it? I would have guessed that the AppDomain stopped/killed and all allocated memory space freed.

Dave Kreskowiak3-Jul-06 9:22

3-Jul-06 9:22

Just because you unloaded an AppDomian, doesn't mean that all the data in it just "went away". Assemblies used by multiple domains in a process can be shared. This means that the assembly is domain-neutral. Data in domain-neutral assemblies in not freed until the entire app shuts down, not just the AppDomain it was allocated in.

You might want to take a look at a couple examples of AppDomain PlugIns.

http://www.devsource.com/article2/0,1759,1790388,00.asp[^]
http://www.google.com/search?hl=en&q=appdomain+plugins[^]
http://msdn.microsoft.com/msdnmag/issues/03/10/Plug-Ins/default.aspx[^]

Dave Kreskowiak
Microsoft MVP - Visual Basic

matsnas3-Jul-06 19:46

3-Jul-06 19:46

Thanks, I'll have a go at the examples you posted.

Just one question though, I was expecting to be able to have other programmers write plugins for my application but using AppDomains I would be able to securly shut these plugins down and unload them without disturbing the plugin host?

Note! Written from memory so there might be compilation errors...

namespace AppDomainHost<br />
  public class Host<br />
<br />
    private mAppDomain as AppDomain<br />
    private mIPlugin as AppDomainInterfaces.IPlugin<br />
<br />
    public sub New()<br />
      Dim vEvidence As Evidence = AppDomain.CurrentDomain.Evidence<br />
      mAppDomain = AppDomain.CreateDomain("MyAppDomain", vEvidence)<br />
      mIPlugin = AppDomainInterfaces.Factory.CreateIPlugin(mAppDomain, "AppDomainClient", "AppDomainClient.Client")<br />
      mIPlugin.Connect<br />
      AppDomain.Unload(mAppDomain)<br />
    end sub <br />
<br />
  end class <br />
end namespace <br />
<br />
namespace AppDomainClient<br />
  <serializable()> _<br />
  public class Client<br />
    implements AppDomainInterfaces.IPlugin<br />
<br />
    private mForm as Form<br />
    public sub New()<br />
      mForm = new Form()<br />
    end sub <br />
<br />
    public sub Connect() implements AppDomainInterfaces.IPlugin.Connect<br />
      msgbox("Connected")<br />
    end sub <br />
  end class <br />
end namespace <br />
<br />
namespace AppDomainInterfaces<br />
  public interface IPlugin<br />
    sub Connect()<br />
  end interface<br />
<br />
  public class Factory<br />
    function CreateIPlugin(byval pAppDomain as AppDomain, byval pAssembly as string, byval pType as string)<br />
      dim vIPlugin = directcast(pAppDomain.CreateInstanceAndUnwrap(pAssembly, pType), IPlugin)<br />
      return vIPlugin<br />
    end function <br />
  end class<br />
end namespace

Dave Kreskowiak5-Jul-06 1:28

5-Jul-06 1:28

I really couldn't tell you. I've done plugin's before, but not in AppDomains. I've never needed the ability to unload plugin's.

Dave Kreskowiak
Microsoft MVP - Visual Basic

matsnas3-Jul-06 20:29

3-Jul-06 20:29

Ok, I'm not sure I understand what happens or what to do about it but as the first article talks about leaking datum into the original AppDomain it seems like loading the Plugin loads an extra assemby into AppDomain.CurrentDomain.

I thougt that I was only calling a sub on the interface object IPlugin. Why is the AppDomainClient.DLL loaded and how do I prevent this? More correctly, how do I assure that my plugin can be removed from memory at any time?

Datetime

vengaqua3-Jul-06 0:01

vengaqua

3-Jul-06 0:01

I am having problem when i make procedure and declare parameter as datetime and when i call it in crysat report it asks for the value and as in the database that is saved as date only it does not return anything.Can anyone tell me what to do?

Mohinder Singh

PDU format

vengaqua2-Jul-06 23:55

vengaqua

2-Jul-06 23:55

What is the PDU format for Long SMS? I am bit confused in this case.

Mohinder Singh

Re: PDU format

Dave Kreskowiak3-Jul-06 2:57

Re: Comparing two Objects

3-Jul-06 2:57

Google is your friend! Results[^] for "PDU format Long SMS"

Dave Kreskowiak
Microsoft MVP - Visual Basic

Sorting

vengaqua2-Jul-06 23:53

vengaqua

2-Jul-06 23:53

How to sort the table column by clicking on particular column?

Mohinder Singh

Re: Sorting

Rey99993-Jul-06 2:11

Rey9999

3-Jul-06 2:11

you could use a datagridview instead of a table. on a datagridview, colums are sorted by clicking on their header.

~~~ From Milano to The Hague, easy as it goes ~~~

Comparing two Objects

alien viper2-Jul-06 23:48

alien viper

2-Jul-06 23:48

Hello all,

Pls, someone help me.
I would like to compare two objects. It's equal value or not.

For Example

Dim emp1 As New Employee()
Dim emp2 As New Employee()

emp1.Name ="John"
emp2.Name ="John"

'emp1.Equals(emp2) return false I what to get true in this 'condition.

I know that emp1 and emp2 is the difference reference address. But I would to get the return True Value when all of it's property value is the same and else false. How do I get it.

Thanks in advance

!alien!

Rey99993-Jul-06 2:08

Rey9999

3-Jul-06 2:08

Overwrite the Equals method.

~~~ From Milano to The Hague, easy as it goes ~~~

Re: Comparing two Objects

Dave Kreskowiak3-Jul-06 2:53

if treviewnode's name is blank after rename how to detact

3-Jul-06 2:53

If this is the way you really want to do it, then you'll either have to supply a Equals override in your Employee class or add a DefaultPropertyAttribute[^] to your class specifying the Name property as the default property if none is specified in the expression.

Dave Kreskowiak
Microsoft MVP - Visual Basic

mini87802-Jul-06 23:37

mini8780

2-Jul-06 23:37

in a treeview,, if i do rename on any node,, by beginedit,,, but,,, after user chage it's name,, how can i detact tht,, wether new name is vbnullstring or not,,, ????????

Re: if treviewnode's name is blank after rename how to detact

Dave Kreskowiak3-Jul-06 2:50