A free IDE for C#, VB.NET, & Boo projects on Microsoft's .NET platform
SharpDevelop is the open-source IDE for the .NET platform. Write applications in languages including C#, VB.NET, F#, IronPython and IronRuby, as well as target rich and reach: Windows Forms or WPF, as well as ASP.NET MVC and WCF. It starts from USB drives, supports read-only projects, comes with integrated unit and performance testing tools, Git, NuGet and a lot more features that make you productive as a developer.
Add-on based IDE adaptable to any developement platform
UniversalIDE is an open source development environment studied to be compatible with any programming language thanks to its add-on based structure. Anyone who knows the .NET Framework can develop add-ons to support a programming language, defining syntax highlighting rules and interfacing the IDE with compilers or interpreters. It is written in Visual Basic .NET, so it requires the .NET Framework to run. The program's GUI is multi-language (actually English and Italian are officially supported, but translating to another language is as easy as editing an XML file). More information in the wiki https://sourceforge.net/p/universalide/wiki/ and in the website http://universalide.sf.net This project uses SharpZipLib: http://icsharpcode.github.io/SharpZipLib/ Some icons are from this creative commons - licensed icon set: http://p.yusukekamiyamane.com/ .
A PSP-Lua Script Editor. Write your lua software for Sony PSP easily testing directly form pc.
On Stop surely a show stopper.
dotView Visual Studio is an open source IDE for dotView PHP framework. Main Functions : syntax highlight, break point and debug, integrating WAMP environement, and RAD tools. Support : PHP5, JS, CSS, HTML, XML, DOJO, JQUERY, SVN, FTP