Sitecore: Detect user in Page Editor mode

Can I know how to detect user is in page editor mode using code? This is because, I have a component, when user browses from page editor, it will search in master_index folder instead of web_index folder.

Please check with : if (Sitecore.Context.PageMode.IsPageEditorEditing)

also is working on Sitecore 6.6, it not depends on Sitecore 7.

Please check also this Sitecore blog post by Martina Welander.

To check if is normal page use: if (Sitecore.Context.PageMode.IsNormal)

To check if is preview mode use: if (Sitecore.Context.PageMode.IsPreview)

Also are others PageMode:

• IsPageEditorClassic
• IsPageEditorDesigning
• IsPageEditorEditing
• IsPageEditorNavigating, etc

If you are curious you can check with Reflector or dotPeek this class: Sitecore.Context.PageMode from Sitecore.Kernel assembly.