I am working on a Visual studio like application i.e. have a toolbox, an editor and property grid similar to VS.
User can drag and drop the controls(custom and third party) to the editor window and perform operations like resize, move, align, group etc.; Properties of that control needs to be displayed in property grid and user can update them from there.
As per my current understanding I will have to extend the Canvas to create my own editor and and Interface for controls which it supports; Each supported control will have to implement this interface so that it can be placed in our editor.
Something similar to this - http://www.codeproject.com/KB/WPF/WPFDiagramDesigner_Part4.aspx
Looking forward for any kind of help, comment or links.