- add a data grid
- add a button in the control bar of the datagrid, set it to open another page, select page and make it default button in settings of the button
- the opened page should be build on the datagrid object
if you wish to add on the line a button you should use a list view wherein you can add a page button.
For a datagrid it is not possible to add a button in everyline. In a template grid you can right click and add a microflow button to open another page.
Mendix is object oriented, so you can pass the object of the row, not a single attribute value.
Create a page and connect it as described in the other answers.
The page should start with a dataview with datasource context and entity equal to the datagrid;
to show the required value, use either a text (read) or input widget (Write)