Dynamically add row in Datagrid in Silverlight

You can have a class which holds the value of the controls whatever you want and maintain a global collection of that class...
ObservableCollection<employee> obj = new ObservableCollection<employee>()
where Employee is your defined class.

Now on button click , you can add the new row like this

Private void AddRows(sender,args){
obj.Add(new Employee() {.... });
 datagrid1.itemsource=obj;
 }