Multivalued parameter in SSRS 2012

I am designing a report using SSRS 2012.

I want to pass multiple transactions id to the report as parameter.

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In the report i have declared @tranid as parameter and set "Allow multiple values" checked.

So how to pass more than one transactions ids through my code ?

and how to write query in the report.

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My code (which is not working)

strids =  "tran1,tran2,tran3"

Dim param1 As New ReportParameter("tranid", strIds, False)

Dim params As New Collections.Generic.List(Of ReportParameter)

 params.Add(param1)

ReportViewer1.ServerReport.SetParameters(params)

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In the report my query, Select * from myTable where transactionNo in (@tranid)

If i pass only one then its working. If i select more than 1 then not working.

h2007