How to show popup window?

To show popup window with System.Windows.Forms.MessageBox.Show(“My message here”); we need to add reference to System.Windows.Forms in sources and then recompile?

To show popup window with System.Windows.Forms.MessageBox.Show(“My message here”); we need to add reference to System.Windows.Forms in sources and then recompile?

No need to recompile as the #r directive can be used in a script to make use of assemblies of your choice. The following code shows a popup window:

#r "System.Windows.Forms"
System.Windows.Forms.MessageBox.Show("My message here");