我如何使用数据表显示数据？ [英] How I show data using data table?

问题描述

我的代码就是这样：

My code just like that:

public List<teacher> GetAsssignCoursesOfTeachers(int departmentId)
       {
           SqlConnectionObj.Open();
           string commandString = String.Format("SELECT tbl_TeacherEntry.Name,tbl_Department.Name,tbl_CourseEntry.CourseName From (((tbl_TeacherEntry INNER JOIN tbl_CourseAssignToTeacher ON tbl_TeacherEntry.Id=tbl_CourseAssignToTeacher.TeacherId) INNER JOIN tbl_Department ON tbl_Department.Id=tbl_CourseAssignToTeacher.DepartmentId) INNER JOIN tbl_CourseEntry ON tbl_CourseEntry.Id=tbl_CourseAssignToTeacher.CourseId)");
           commandString += String.Format(" where tbl_CourseAssignToTeacher.DepartmentId=@departmentId");
           SqlCommandObj.CommandText = commandString;
           SqlCommandObj.Parameters.Clear();
           SqlCommandObj.Parameters.Add("@departmentId", SqlDbType.Int);
           SqlCommandObj.Parameters["@departmentId"].Value = departmentId;
           SqlDataReader aDataReader = SqlCommandObj.ExecuteReader();
          List<teacher> teachers=new List<teacher>();
           while (aDataReader.Read())
           {
               Teacher anotherTeacher = new Teacher();
               anotherTeacher.Name = aDataReader["Name"].ToString();
               anotherTeacher.ADepartment.DepartmentName = aDataReader["Name"].ToString();
               anotherTeacher.ACourse.CourseName = aDataReader["CourseName"].ToString();
               teachers.Add(anotherTeacher);
           }
           return teachers;
       }

推荐答案

public DataSet GetAsssignCoursesOfTeachers(int departmentId)
    {
        DataSet dsTemp = new DataSet();
        SqlDataAdapter daTemp;
        SqlConnectionObj.Open();
        string commandString = String.Format("SELECT tbl_TeacherEntry.Name,tbl_Department.Name,tbl_CourseEntry.CourseName From (((tbl_TeacherEntry INNER JOIN tbl_CourseAssignToTeacher ON tbl_TeacherEntry.Id=tbl_CourseAssignToTeacher.TeacherId) INNER JOIN tbl_Department ON tbl_Department.Id=tbl_CourseAssignToTeacher.DepartmentId) INNER JOIN tbl_CourseEntry ON tbl_CourseEntry.Id=tbl_CourseAssignToTeacher.CourseId)");
        commandString += String.Format(" where tbl_CourseAssignToTeacher.DepartmentId=@departmentId");
        SqlCommandObj.CommandText = commandString;
        SqlCommandObj.Parameters.Clear();
        SqlCommandObj.Parameters.Add("@departmentId", SqlDbType.Int);
        SqlCommandObj.Parameters["@departmentId"].Value = departmentId;
        daTemp = new SqlDataAdapter(SqlCommandObj);
        daTemp.Fill(dsTemp);

        return dsTemp;
        //SqlDataReader aDataReader = SqlCommandObj.ExecuteReader();
        //List<teacher> teachers = new List<teacher>();
        //while (aDataReader.Read())
        //{
        //    Teacher anotherTeacher = new Teacher();
        //    anotherTeacher.Name = aDataReader["Name"].ToString();
        //    anotherTeacher.ADepartment.DepartmentName = aDataReader["Name"].ToString();
        //    anotherTeacher.ACourse.CourseName = aDataReader["CourseName"].ToString();
        //    teachers.Add(anotherTeacher);
        //}
        
    }
</teacher></teacher>

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