I want to list some issues that I've noticed.

1. C:\Projects\Samples\Z39.50\Zoom.Net\HelloWorld\Class1.cs

should use PrefixQuery, e.g @"@attr 1=4 ""Gong""" , not simple query "isbn=0253333490"

2. It is required to download latest YAZ from http://www.indexdata.com/yaz/

and copy DLLs from YAZ\BIN to \Zoom.Net.YazSharp\yaz

to build \YazSharp for Windows successfully.

3. In YazSharp for Windows during search I've got:
An unhandled exception of type 'System.InvalidOperationException'  Additional information: Cross-thread operation not valid: Control 'btnSearch' accessed from a thread other than the thread it was created on.

I’ve followed suggestion from “How to solve "Cross thread operation not valid" and added to beginning of PerformSearch

            if (this.InvokeRequired)

                this.Invoke(new MethodInvoker(PerformSearch));