Trying to create generic object: SOLVED
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As usual, as soon as I post, if figure it out; sorry. :( This Me._Column = Activator.CreateInstance(GetType(T))() Should be this Me._Column = Activator.CreateInstance(GetType(T)). However, now I have another problem; I'll work on this awhile. I hope I am in the right group. I have a Class that creates an xml file that currently works. However, I would like to change the definition to define 1 of 2 generic types (T) when creating the file; Column1 or Column2. The code below is what I have come up with through searches. Everything compiles but when I create an instance of MyXmlDef I get this error. 'No Default Member Found for type 'Column1' A search on the error says: A late-bound index Get or Set call has been attempted. Ensure that the object has a default property with a Get or Set, depending on which you are trying to make. I have tried to define a Property for Column below but it doesn't fix the error. I don't know what 'object' the error refers to. Can someone help? Thank you ' I am just showing the relevant code ' I have hardcoded this to Column1 to test public Class MyXmlDef _ Public _ColumnList As ColumnList(Of Column1) Public Sub New() Me._ColumnList = New ColumnList(Of Column1) end sub end Class Class ColumnList(Of T) _ Public _Column As T ' This is test code to try and fix the error; it doesn't fix. Public Property Column() As T Get Return Me._Column End Get Set(ByVal value As T) Me._Column = value End Set End Property Public Sub New() ' THis is the code I found on the internet to create an object from generic. ' However, it does not compile. ' Me._Column = Activator.CreateInstance(T)() ' This compiles but get the error described above for Column1. ' I do not know if this is valid or not. Me._Column = Activator.CreateInstance(GetType(T))() End Sub End Class Class Column1 _ Public _ProductName As XMLProductName ' ... other XmlElments Public Sub New() '... initialize elements end sub End Class Class Column2 _ Public _ProductName As XMLProductName ' ... o
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As usual, as soon as I post, if figure it out; sorry. :( This Me._Column = Activator.CreateInstance(GetType(T))() Should be this Me._Column = Activator.CreateInstance(GetType(T)). However, now I have another problem; I'll work on this awhile. I hope I am in the right group. I have a Class that creates an xml file that currently works. However, I would like to change the definition to define 1 of 2 generic types (T) when creating the file; Column1 or Column2. The code below is what I have come up with through searches. Everything compiles but when I create an instance of MyXmlDef I get this error. 'No Default Member Found for type 'Column1' A search on the error says: A late-bound index Get or Set call has been attempted. Ensure that the object has a default property with a Get or Set, depending on which you are trying to make. I have tried to define a Property for Column below but it doesn't fix the error. I don't know what 'object' the error refers to. Can someone help? Thank you ' I am just showing the relevant code ' I have hardcoded this to Column1 to test public Class MyXmlDef _ Public _ColumnList As ColumnList(Of Column1) Public Sub New() Me._ColumnList = New ColumnList(Of Column1) end sub end Class Class ColumnList(Of T) _ Public _Column As T ' This is test code to try and fix the error; it doesn't fix. Public Property Column() As T Get Return Me._Column End Get Set(ByVal value As T) Me._Column = value End Set End Property Public Sub New() ' THis is the code I found on the internet to create an object from generic. ' However, it does not compile. ' Me._Column = Activator.CreateInstance(T)() ' This compiles but get the error described above for Column1. ' I do not know if this is valid or not. Me._Column = Activator.CreateInstance(GetType(T))() End Sub End Class Class Column1 _ Public _ProductName As XMLProductName ' ... other XmlElments Public Sub New() '... initialize elements end sub End Class Class Column2 _ Public _ProductName As XMLProductName ' ... o
You just need a constraint on your generic type parameter:
Class ColumnList(Of T As New)
...
Public Sub New()
Me._Column = New T()
End Sub
...Generic Types in Visual Basic (Visual Basic) | Microsoft Docs[^]
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