convert string values to itextsharp.text.rectangle in vb.net

Question

How to convert string values to itextsharp.text.rectangle value in vb.net.?

I have tried

"Dim rectangle As iTextSharp.text.Rectangle = New iTextSharp.text.Rectangle("226.5;168;324.731;80.57574")"

I got this error

'Public Sub New(rect As iTextSharp.text.Rectangle)': Value of type 'String' cannot be converted to 'iTextSharp.text.Rectangle'. Please suggests if any ideas.