Partly working

Tanshu.Accounts.Contracts/Data Contracts/FoodTableBO.cs

@@ -0,0 +1,11 @@
+using System;
+using System.Runtime.Serialization;
+
+namespace Tanshu.Accounts.Contracts
+{
+    public class FoodTableBO
+    {
+        public int TableID { get; set; }
+        public string Name { get; set; }
+    }
+}

Tanshu.Accounts.Contracts/Data Contracts/SalesBillItemBO.cs

@@ -18,7 +18,7 @@ namespace Tanshu.Accounts.Contracts
             get { return price; }
             set
             {
-                if (value <= 0)
+                if (value < 0)
                     throw new ArgumentException("Price has to be non-negative greater than zero.");
                 else
                     price = value;