programatically add user permission to a list in sharepoint

Question

how do i programatically add user permission to a list in sharepoint. i want to add the permission "Contribute" to a user or group for a certain list. im using c#

Thanks..

Answer 1

You can do this using the SPRoleAssignment object, e.g.

// Assuming you already have SPWeb and SPList objects
...
SPRoleAssignment roleAssignment = new SPRoleAssignment("dom\\user", "user@dom", "user", "some notes");
SPRoleDefinition roleDefinition = web.RoleDefinitions.GetByType(SPRoleType.Contributor);
roleAssignment.RoleDefinitionBindings.Add(roleDefinition);
if (!myList.HasUniqueRoleAssignments)
{
    myList.BreakRoleInheritance(true); // Ensure we don't inherit permissions from parent
} 
myList.RoleAssignments.Add(roleAssignment);
myList.Update();

Answer 2

but what if we want to assign this permission to the group by the same way ?