A small error(thread)

Question

1.00/5 (2 votes)

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I keep getting the following error:
""Delegate 'system.windows.forms.methodinvoker'
requires an 'AddressOf'expression or
lambda expression as the only argument to its constructor.""

Please Help Me.
-----------my code------------------

VB

Public Sub search()
        Try

            cmdoledb.CommandText = "SELECT NAME FROM table1 WHERE ID=" & CInt(txtid.Text)
            cmdoledb.CommandType = CommandType.Text
            cmdoledb.Connection = cnnoledb
            Dim rdroledb As OleDbDataReader = cmdoledb.ExecuteReader
            While rdroledb.Read = True
                updatetext(rdroledb.Item(0).ToString)
                Thread.Sleep(2000)
                tictac()
            End While
            t1.Abort()
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
        cmdoledb.Dispose()
    End Sub
    Private Sub updatetext(ByVal text)
        If Me.InvokeRequired Then
            Me.Invoke(Me.Invoke(New MethodInvoker(AddressOf updatetext, text)))
        Else
            txtnam.Text &= text
        End If
    End Sub

Posted 19-May-10 9:07am

ehsan6000

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Christian Graus 19-May-10 16:15pm

Reason for my vote of 1
Not for the dumb question, but for asking it again, after I answered it.

William Winner 19-May-10 16:28pm

Reason for my vote of 1
inability to understand a simple error message

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William Winner · Answer 1 · 2010-05-19T10:28:00

Do you not understand the English in the error? Is that the problem?

MethodInvoker does not have an overload that allows for multiple parameters. The error tells you everything:

ehsan6000 wrote:
Delegate 'system.windows.forms.methodinvoker'
requires an 'AddressOf'expression or
lambda expression as the only argument to its constructor.

MethodInvoker only takes one argument. If you want to pass a parameter, you do that in the Invoke...as in:

VB

Me.Invoke(New MethodInvoker(AddressOf updatetext),New Object(){text})

and Christian is right...what's up with Me.Invoke twice? You need to try to understand what you're writing before doing it.

Christian Graus · Answer 2 · 2010-05-19T09:44:00

Your basic issue is a combination of cluelessness and illiteracy. I assume, despite you not telling us, that this line is the error:

ehsan6000 wrote:
Me.Invoke(Me.Invoke(New MethodInvoker(AddressOf updatetext, text)))

Why are you calling me.invoke twice ? Is it because

a - this is actually right, me.invoke returns the same thing as AddressOf

b - you get an error after copying code blind off the web, so ask here because you can't use google, can't read, and have no idea what you're doing ( and therefore cannot diagnose the problem ) ?

Oh, your code is still terrible - SQL in the presentation layer, the assumption that a textbox contains an int, etc. What happens if someone types text in to that textbox ?

A small error(thread)

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