create an instance with a string Name

[wu jianhua]

hi.
If I have a form, like FrmAbout, can I create a form instance only with a
string "FrmAbout"?
not like : Form frm = new FrmAbout();
I want the code : Form frm = createInstance( "FrmAbout" );
How to code my createInstance function?

Thanks.

 

[Guest]

There are several ways. You can use Activator.CreateInstance() or
Type.InvokeMember. I don't remember the pros and cons of these methods but
you can probably find out which is most appropriate for your application.

http://msdn.microsoft.com/library/d...rfsystemactivatorclasscreateinstancetopic.asp

http://msdn.microsoft.com/library/d...tml/frlrfsystemtypeclassinvokemembertopic.asp

 

[Michael Nemtsev]

Hello wu,

See this code. Comments expain how it works

// Get current assembly
Assembly frmMain = Assembly.GetEntryAssembly();
// Get Type of your form
System.Type formType = frmMain.GetType("WindowsApplication1.frmAbout");
// Create instance of form
object pc = Activator.CreateInstance(formType);
// Cast to Form class
Form frm = (Form)pc;
// Show Form
frm.Show();

wj> hi.
wj> If I have a form, like FrmAbout, can I create a form instance only
wj> with a
wj> string "FrmAbout"?
wj> not like : Form frm = new FrmAbout();
wj> I want the code : Form frm = createInstance( "FrmAbout" );
wj> How to code my createInstance function?
wj> Thanks.

---
WBR,
Michael Nemtsev :: blog: http://spaces.msn.com/laflour

"At times one remains faithful to a cause only because its opponents do not
cease to be insipid." (c) Friedrich Nietzsche

 

[Michael Nemtsev]

Hello Michael ,

And instead of using Assembly u can change these 2 lines below

// Get current assembly
Assembly frmMain = Assembly.GetEntryAssembly();
// Get Type of your form
System.Type formType = frmMain.GetType("WindowsApplication1.frmAbout");

on this

Type formType = typeof(WindowsApplication1.frmAbout);

MN> Hello wu,
MN>
MN> See this code. Comments expain how it works
MN>
MN> // Get current assembly
MN> Assembly frmMain = Assembly.GetEntryAssembly();
MN> // Get Type of your form
MN> System.Type formType =
MN> frmMain.GetType("WindowsApplication1.frmAbout");
MN> // Create instance of form
MN> object pc = Activator.CreateInstance(formType);
MN> // Cast to Form class
MN> Form frm = (Form)pc;
MN> // Show Form
MN> frm.Show();
wj>> hi.
wj>> If I have a form, like FrmAbout, can I create a form instance only
wj>> with a
wj>> string "FrmAbout"?
wj>> not like : Form frm = new FrmAbout();
wj>> I want the code : Form frm = createInstance( "FrmAbout" );
wj>> How to code my createInstance function?
wj>> Thanks.
MN> ---
MN> WBR,
MN> Michael Nemtsev :: blog: http://spaces.msn.com/laflour
MN> "At times one remains faithful to a cause only because its opponents
MN> do not cease to be insipid." (c) Friedrich Nietzsche
MN>
---
WBR,
Michael Nemtsev :: blog: http://spaces.msn.com/laflour

"At times one remains faithful to a cause only because its opponents do not
cease to be insipid." (c) Friedrich Nietzsche

 

[Michael Nemtsev]

Hello rmacias,

The IDasm code is similar, except that InvokeMemeber just call virtual function
InvokeMember and CreateInstance is direct call
Using CreateInstance is more readable


r> There are several ways. You can use Activator.CreateInstance() or
r> Type.InvokeMember. I don't remember the pros and cons of these
r> methods but you can probably find out which is most appropriate for
r> your application.
r>
r> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpre
r> f/html/frlrfsystemactivatorclasscreateinstancetopic.asp
r>
r> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpre
r> f/html/frlrfsystemtypeclassinvokemembertopic.asp
r>
r> "wu jianhua" wrote:
r>---
WBR,
Michael Nemtsev :: blog: http://spaces.msn.com/laflour

"At times one remains faithful to a cause only because its opponents do not
cease to be insipid." (c) Friedrich Nietzsch

 

[wu jianhua]

it is so great.
Thanks to all.

 

[Joanna Carter [TeamB]]

"wu jianhua" <[email protected]> a écrit dans le message de (e-mail address removed)...


| If I have a form, like FrmAbout, can I create a form instance only with a
| string "FrmAbout"?
| not like : Form frm = new FrmAbout();
| I want the code : Form frm = createInstance( "FrmAbout" );
| How to code my createInstance function?

Take a look at Activator.CreateInstance(...)

Joanna