asked on

Loading a class from a string with a class name.

I don't no if this is easy to do?

I would like to make a function like

FillCombo(ddControl, CollectionClass, ValueField, TextField, NeedsNullValueRow)

this is the code that works:

Dim BuyerCol As New Csb.EabOrder.EabOrderBuyerCollection
BuyerCol.LoadAll()
Dim buyer As Csb.EabOrder.EabOrderBuyer

dropdown.Items.Clear()
Dim FirstlistItem As New ListItem("", "")
dropdown.Items.Add(FirstlistItem)

For Each Buyer In BuyerCol
Dim listItem As New ListItem(Buyer.BuyerName, Buyer.BuyerId)
dropdown.Items.Add(listItem)
Next

Thanks.

Mohamed Zedan

I don't get what you want ?

keezebees

ASKER

Sorry, should be al little more specific.

What i want is an function that automates the listed code
To do that I would have to be able to make an instance of the some classes just by there class name (string)
And thats what my problem is.

How do ik load the class 'Csb.EabOrder.EabOrderBuyer' as an instance based on only a class name??

public Function FillCombo(ddControl as dropdownlist, CollectionClassName as string, ValueField as string, TextField as string, NeedsNullValueRow as boolean) as boolean

Hope this is more clear.

ASKER CERTIFIED SOLUTION

Mohamed Zedan

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keezebees

ASKER

Thanks mohzedan.

Any Idea why i get an 'object reference not set to an instance of an object' error??

NullReference exception was unhandled by user code

Private Sub test()
Dim asm As System.Reflection.Assembly = System.Reflection.Assembly.GetExecutingAssembly
Dim instance As Object = asm.CreateInstance("csb.EabOrder.EabOrderVerkoopOrderViewCollection")

'object reference error is here!!!!!
Dim Enumer As IEnumerator = CType(instance, IEnumerable).GetEnumerator
While Enumer.movenext
Dim buyer As Object = Enumer.Current
'Work with the buyer object
End While

End Sub

Mohamed Zedan

try using eaborderverkooporderviewCollection
only in the createinstance...
and could you run this code
after dim asm .....

Dim types As Type() = asm.GetTypes
for i as integer = 0 to asm.length-1
Console.writeline(asm(i).Name)
next

and the names of the types that are printed are the names you could load using this way.
i.e. asm.createinstance("name of type from the list printed")

Mohamed Zedan

the exception is because the type name wasn't found in that assembly ... if it is contained in a dll then that dll should be loaded ... if that type is in your namespace just check it's type name correctly ...

keezebees

ASKER

ehh...

asm.length doesnt excists....

Must be getting to late for me:)

Mohamed Zedan

sorry i meant types.length must be too late for me too . :)

keezebees

ASKER

Like this right?

Dim asm As System.Reflection.Assembly = System.Reflection.Assembly.GetExecutingAssembly
Dim instance As Object = asm.CreateInstance("Csb.EabOrder.EabOrderVerkoopOrder")

Dim types As Type() = asm.GetTypes
For i As Integer = 0 To types.Length - 1
MsgBox(types(i).Name)
Next

Mohamed Zedan

yes but instead of the msgbox use console.writeline(types(i).name)

that way you'll have them written in the output window

keezebees

ASKER

Here is the output:

MyComputer
MyProject
ThreadSafeObjectProvider`1
desktopmodules_csb_eaborder_editcsb_eaborder_ascx
EditCsb_EabOrder
desktopmodules_csb_eaborder_viewcsb_eaborder_ascx
ViewCsb_EabOrder
desktopmodules_csb_eaborder_settings_ascx
Settings
FastObjectFactory_app_web_yu75jgso
MyComputer
MyProject
ThreadSafeObjectProvider`1
desktopmodules_csb_eaborder_editcsb_eaborder_ascx
EditCsb_EabOrder
desktopmodules_csb_eaborder_viewcsb_eaborder_ascx
ViewCsb_EabOrder
desktopmodules_csb_eaborder_settings_ascx
Settings
FastObjectFactory_app_web_yu75jgso

keezebees

ASKER

Sorry mohzedan,

Have to go now.
Will be back for another go tomorrow.

Thanks.

Mohamed Zedan

see you tomorrow :)

keezebees

ASKER

A bit late, but here are your points.
Just got it to work

Thanks.

Mohamed Zedan

Sorry for being too late :)

Mohamed Zedan

If you need any more info post here ok ... :)

keezebees

ASKER

well,

what i did was just write my code the way i would normaly do.
Do the testing making sure that I dont need to come back no more.
And then i replaced my object declaration with:

Dim instance As Object = asm.CreateInstance(CollectionClassName)

intellisence obviusly wont work, but hey, who needs intellisence.........well actuali I do but dont tell anyone Ok?

can you tell me a bit more about supporting Ienumerable in a class so i could do the enumerating?

Mohamed Zedan

What is your collection class like ?

keezebees

ASKER

I am using EntitySpaces for my DAL

You know of that??

Mohamed Zedan

I just read about it .... your collections should already implement Ienumerable