Not the whole Solution but a part of it.
This code-snippet gives the Project-path :
Dim dte As EnvDTE.DTE = System.Runtime.InteropServices.Marshal.GetActiveObject("VisualStudio.DTE")
Dim dir As String = Path.GetDirectoryName(dte.Solution.FullName)
To get it work it is necessary to add a reference to "Microsoft.Development Environment"
see also :
Referencing the DTE Object[
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