Most probably, you’ll come across situation where you need to use a third-party control in your project. Ever thought about how to add them in your Visual Studio toolbox. Just simple.
Step 1: Right-Click on your toolbox & select ‘Add Tab’.

Step 2: Give a name to the tab, relating to the control you are trying to add; say ‘My Control 1’

Step 3: Right-Click on ‘My Control 1’ and select ‘Choose Items…’

Step 4: From the dialogue-box, click ‘Browse’ button.

Step 5: Browse your control and hit OK. Your control is added.
Now, for using the control you only have to drag-drop the control to your web-page.
Hope this helped.
Thanks