修正项目个人得分问题：统计时只计算项目成员，user_grade表user_id和project_id联合不重复验证，user_grade分数部位负验证

app/controllers/members_controller.rb

@@ -122,7 +122,7 @@ class MembersController < ApplicationController
             user_ids = attrs.delete(:user_ids)
             user_ids.each do |user_id|
               members << Member.new(:role_ids => params[:membership][:role_ids], :user_id => user_id)
-              user_grades << UserGrade.new(:user_id => user_id, :course_id => @course.id)
+              #user_grades << UserGrade.new(:user_id => user_id, :course_id => @course.id)
               if (params[:membership][:role_ids] && params[:membership][:role_ids][0] == "3")
                 course_info << CourseInfo.new(:user_id => user_id, :course_id => @course.id)
               end

app/models/user_grade.rb

@@ -2,4 +2,37 @@ class UserGrade < ActiveRecord::Base
   # attr_accessible :title, :body
   attr_accessible :user_id, :project_id, :grade
   belongs_to :project
+  before_save :correct_score
+  validates_uniqueness_of :user_id, :scope => [:project_id]
+  #validate :my_validation
+
+  #修正分数
+  #分数小于0时修正为0
+  #分数大于等于0时不修正  -by zjc
+  def correct_score
+    if !self.grade.nil? && self.grade < 0
+      self.grade = 0
+    end
+  end
+
+  #def self.exit_user_and_project(user,project)
+  #  unless user.nil? || project.nil?
+  #    if user.class.to_s == 'User' && project.class.to_s == 'Project'
+  #      user_grade = UserGrade.find_by_user_id_and_project_id(user.id,project.id)
+  #      user_grade
+  #    else
+  #      nil
+  #    end
+  #  else
+  #    nil
+  #  end
+  #end
+
+  #def my_validation
+  #  if user_id.nil? || project_id.nil?
+  #    errors[:Base] << "用户和项目不能为空"
+  #  elsif UserGrade.exit_user_and_project(user_id,project_id)
+  #    errors[:Base] << "当前记录已存在"
+  #  end
+  #end
 end