Creating dynamic forms from a varible name

[salportaro]

Hello:

Here is the situation. VB.NET

I have several forms and I have a XML file that can start with a
particular for for debugging/layout reasons. This is a mdi project.
Normaly you would load a form as follows:

Dim frmT As frmTrans
frmT = New frmTrans
frmT.formDate = Now.Date
frmT.MdiParent = Me
frmT.Show()

Thus you could have a menu option to kick off a child form. What I
need is a way to have the form class as a varible name. Such as:

dim f as string = "frmTrans"
Dim frmT As f
frmT = New frmTrans
frmT.formDate = Now.Date
frmT.MdiParent = Me
frmT.Show()

Is there a way of doing this?

Thanks,

Sal

sfp04212005

[Simon Verona]

I think you need to use reflection for this..

I do something similar, using an XML based menu structure with each menu
loading a dll and calling a function... The function may in turn load a
form.

This is done using the following function which is called such as follows:

obj=loadmebynam e("myclassfilen ame.dll","mycla ss",nothing)
obj.functionnam e
Hope this helps.. function follows:
Regards
Simon
Public Shared Function LoadMeByName(By Val vstrAssemblyNam e As String, ByVal
vstrClassName As String, ByVal vArgs() As Object) As Object

'************** *************** *************** *************** *************** **********

'dynamically load object from assembly for late binding purpose

'
*************** *************** *************** *************** *************** **********

Dim objAssembly As Reflection.Asse mbly

Dim objtemp As Object

Dim Params() As Object

'MsgBox(Applica tion.StartupPat h)

Try

If Dir(Application .StartupPath & "\" & vstrAssemblyNam e).Equals("") Then

Err.Raise(-1, "LoadMeByNa me", "assembly could not found, wrong assembly name
given ")

Exit Function

End If

objAssembly = objAssembly.Loa dFrom(Applicati on.StartupPath & "\" &
vstrAssemblyNam e)

objtemp = objAssembly.Cre ateInstance(vst rClassName, True,
Reflection.Bind ingFlags.Create Instance, Nothing, vArgs, Nothing, Nothing)

If objtemp Is Nothing Then

Err.Raise(-1, "LoadMeByNa me", "assembly could not found, wrong assembly name
given ")

Exit Function

End If

' LoadMeByName = objtemp

Return objtemp

Catch

End Try

End Function

<sa********@gma il.com> wrote in message
news:11******** **************@ l41g2000cwc.goo glegroups.com.. .

Hello:

Here is the situation. VB.NET

I have several forms and I have a XML file that can start with a
particular for for debugging/layout reasons. This is a mdi project.
Normaly you would load a form as follows:

Dim frmT As frmTrans
frmT = New frmTrans
frmT.formDate = Now.Date
frmT.MdiParent = Me
frmT.Show()

Thus you could have a menu option to kick off a child form. What I
need is a way to have the form class as a varible name. Such as:

dim f as string = "frmTrans"
Dim frmT As f
frmT = New frmTrans
frmT.formDate = Now.Date
frmT.MdiParent = Me
frmT.Show()

Is there a way of doing this?

Thanks,

Sal

sfp04212005

[rmacias]

Try using reflection by importing the System.Reflecti on namespace. You can
do something like this:

Dim currentAsm As [Assembly] 'Instance of current executing assembly
Dim asmTypes() As Type 'An array of all type of the executing
assembly
Dim typeNamespace As String 'the namespace of a given type
Dim constructorArgu ments() As Object 'any parameters you pass for the New()
Dim typeToCreate As String = "frmTrans" 'The name of the type you want
Dim instanceOfType As Object 'The actual instance of the type.

'Create instance of executing assembly
currentAsm = [Assembly].GetExecutingAs sembly()

'Get the types from the assembly
asmTypes = currentAsm.GetT ypes()

'Iterate through the types and find the one you want
For Each objType As Type In asmTypes
'Get the namespace of the current type
typeNamespace = objType.Namespa ce & "."

'If we find a match, then create an instance of that type
If Type.GetType(ty peNamespace & typeToCreate, False, True) Is objType Then
'Create your arguments if necessary
args = new object() {"argument1" }

'Create instance of type
instanceOfType = objType.InvokeM ember(Nothing, _
BindingFlags.Pu blic Or BindingFlags.No nPublic Or _
BindingFlags.In stance Or BindingFlags.Cr eateInstance _
, Nothing, Nothing, args)
End If
Next

Doing a search on Reflection and pull up other examples. Hope this helps.

"sa********@gma il.com" wrote:

Hello:

Here is the situation. VB.NET

I have several forms and I have a XML file that can start with a
particular for for debugging/layout reasons. This is a mdi project.
Normaly you would load a form as follows:

Dim frmT As frmTrans
frmT = New frmTrans
frmT.formDate = Now.Date
frmT.MdiParent = Me
frmT.Show()

Thus you could have a menu option to kick off a child form. What I
need is a way to have the form class as a varible name. Such as:

dim f as string = "frmTrans"
Dim frmT As f
frmT = New frmTrans
frmT.formDate = Now.Date
frmT.MdiParent = Me
frmT.Show()

Is there a way of doing this?

Thanks,

Sal

sfp04212005