dll compilation error

Question

I have created a C# window application that contains the namespaces System and System.Data Additionally, I have added Microsoft.SqlServer.Smo. When I try to compile from command prompt it shows the error as: then i navigate to G:\SqlDisc:> csc /target:library /r:Micrsoft.SqlServer.Smo.Dll SqlSmoDiscovery.cs but it shows the erroe as error CS0006: Metadata file 'Microsoft.SqlServer.Smo.dll' could not be found