Main Screen fixes

Added confimation dialogues for deleting parts/products;
Finished implementing Product class methods;
Propogating part modifications to associated products;
Stopped deleting of items if there is an association;

C968Project/Product.cs

@@ -4,7 +4,7 @@ namespace C968Project;
 
 public class Product
 {
-    public BindingList<Part> AssociatedParts { get; set; }
+    public BindingList<Part> AssociatedParts { get; set; } = new();
     public int ProductId { get; set; }
     public string Name { get; set; }
     public float Price { get; set; }
@@ -12,15 +12,39 @@ public class Product
     public int Min { get; set; }
     public int Max { get; set; }
     
-    public void AddAssociatedPart(Part part){}
+    public void AddAssociatedPart(Part part)
+    {
+        if (AssociatedParts.Contains(part))
+        {
+            MessageBox.Show($"Product {Name} already has an association with part {part.Name}", "", MessageBoxButtons.OK, MessageBoxIcon.Error);
+            return;
+        }
+
+        AssociatedParts.Add(part);
+    }
 
     public bool RemoveAssociatedPart(int partIndex)
     {
-        return false;
+        var part = LookupAssociatedPart(partIndex);
+
+        if (part is null)
+        {
+            MessageBox.Show($"An error occured while trying to locate the part at index {partIndex}.", "", MessageBoxButtons.OK, MessageBoxIcon.Error);
+            return false;
+        }
+
+        AssociatedParts.Remove(part);
+        return true;
     }
 
-    public Part LookupAssociatedPart(int partIndex)
+    public Part? LookupAssociatedPart(int partIndex)
     {
-        return null;
+        if (partIndex > AssociatedParts.Count)
+        {
+            MessageBox.Show($"Error trying to locate part at index {partIndex}. Out of bounds.", "", MessageBoxButtons.OK, MessageBoxIcon.Error);
+            return null;
+        }
+
+        return AssociatedParts[partIndex];
     }
 }