Visual Studio since 2002 (.Net 1.0) has been partly written in C#/WinForms and then C#/WPF. Visual Interdev (from which the current Visual Studio lineage descen

Visual Studio since 2002 (.Net 1.0) has been partly written in C#/WinForms and then C#/WPF. Visual Interdev (from which the current Visual Studio lineage descends) was partly written in VJ++. It was these bits that were ported to C#/COOL for the 2002 release.