How to customize the file filters in Add Existing Item dialog

Hi,

We have added our own file type say .myfile and .myfile2 via a package, then can add these files to a C# unit test project.

However, each time when open the Add Existing Item dialog, the default displayed files will be filtered some filter. See below,

After some investigation, we find that maybe we can provide our own filter from our own package, just like your "Visual Studio Class Designer Package" does.

I can easily use its filter value by below way,

The 108 is a value defined in the related DLLs of "Visual Studio Class Designer Package", Microsoft.VisualStudio.EnterpriseTools.ClassDesigner.dll or its satellite DLL Microsoft.VisualStudio.EnterpriseTools.ClassDesignerUI.dll.

Could you help me look into how the 108 value is defined in the class designer package?

Regards,

Jaron