Anpassung Grades

EF_Code_First/Models/Grade.cs

@@ -9,7 +9,7 @@ namespace EF_Code_First.Models
         public int GradeId { get; set; }
         public string? GradeName { get; set; }
         public string? Section { get; set; }
-        [ForeignKey("StudentId")]
+        //[ForeignKey("StudentId")]
         public ICollection<Student>? Students { get; set; }
 
 
@@ -20,7 +20,11 @@ namespace EF_Code_First.Models
             builder.Append('\u002C');
             builder.Append(GradeName);
             builder.Append('\u002C');
-            builder.Append(Students.Count);
+            if (Students != null)
+            {
+                builder.Append(Students.Count);
+            }
+            
             return builder.ToString();
         }
     }

EF_Code_First/Program.cs

@@ -8,27 +8,18 @@ namespace EF_Code_First
     public class Program
     {
         static void Main(string[] args)
+        {
+            AddStudent();
+            ShowStudentsWithGrade();
+            
+        }
+        static public void ShowStudentsWithGrade()
         {
             using (var ctx = new SC_DbContext())
             {
-                /*
-                var grade = ctx.Grades.Single(g => g.GradeId == 5);
 
-                
-                var stud = new Student()
-                {
-                    StudentName = "Michael Maier",
-                    Weight = (float?)102, 
-                    Height = (decimal?)175,
-                    DateOfBirth = DateTime.Parse("1970-10-11"),
-                    Grade = grade
-                };
-                Console.WriteLine($"new Student: {stud}");
-                ctx.Students.Add(stud);
-                ctx.SaveChanges();
-                */
                 List<Grade> grades = ctx.Grades
-                    .Include(st=> st.Students)
+                    .Include(st => st.Students)
                     .ToList();
                 foreach (var grade in grades)
                 {
@@ -36,19 +27,41 @@ namespace EF_Code_First
                 }
 
                 List<Student> students = ctx.Students
-                    .Include(g=> g.Grade)
+                    .Include(g => g.Grade)
                     .ToList();
-                
+
 
                 foreach (var s in students)
                 {
-                    Console.WriteLine(s.ToString());    
+                    Console.WriteLine(s.ToString());
                 }
+
+                Console.WriteLine(ctx.DbPath);
+            }
+
+        }
+
+        static public void AddStudent()
+        {
+            using (var ctx = new SC_DbContext())
+            {
+                var grade = ctx.Grades.Single(g => g.GradeId == 5);
+
+
+                var stud = new Student()
+                {
+                    StudentName = "Michael Maier",
+                    Weight = (float?)102,
+                    Height = (decimal?)175,
+                    DateOfBirth = DateTime.Parse("1970-10-11"),
+                    G_Id = grade.GradeId,
+                    Grade = grade
+                };
+                Console.WriteLine($"new Student: {stud}");
+                ctx.Students.Add(stud);
+                ctx.SaveChanges();
                 
-                Console.WriteLine (ctx.DbPath);
-               
-               
-                             
+
             }
         }
     }