cast structure in thread

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i have a structure that i try to case in background worker, but no success i get

private Jobs as list(of jobitems)
Structure JobItem
        Dim Index As Integer
        Dim Url As String
        Dim Status As String
End Structure

i get this error

TryCast' operand must be reference type, but is a value type

in background worker

 Private Sub DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs)
        Dim worker As BackgroundWorker = TryCast(sender, BackgroundWorker)
        Dim workItem As String = TryCast(e.Argument, String)

        If worker IsNot Nothing AndAlso workItem IsNot Nothing Then
            'Process the work item here.
            Dim jb As New JobItem
            jb.Status = "Starting" & Jobs(CInt(workItem)).Url
            worker.ReportProgress(CInt((Jobs.Count / 100) * urlIndex), jb)
        End If
    End Sub


Private Sub ProgressChanged(ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs)

 Dim jb As JobItem = TryCast(e.UserState, JobItem)

End Sub

how do i fix this,

thanks

Posted 4-Jun-11 10:08am

Cool Smith

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Tarun.K.S · Accepted Answer · 2011-06-04T10:38:00

Hi, you have to use CType instead of TryCast. TryCast expects the parameters that you have passed to of Reference Type but JobItem is a Structure which is a Value type and hence the error. Which is not the case with CType.

This should work now:

VB

Private Sub ProgressChanged(ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs)
 Dim jb As JobItem = CType(e.UserState, JobItem)
End Sub

:)