Question

I am trying to map a class from SQL to a linq collection, But I fail..

I have got this class:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Linq;
using System.Data.Linq.Mapping;

namespace SportsStore.Entities
{
    [Table(Name = "Products")]
    public class Product 
    {
        [Column(IsPrimaryKey = true, IsDbGenerated = true, AutoSync = AutoSync.OnInsert)]
        public int ProductID { get; set; }

        [Column]public string Name { get; set; }
        [Column]public string Description { get; set; }
        [Column]public `int` Price { get; set; } 
        [Column]public string Category { get; set; }

    }
}

I call that class from another class:

using SportsStore.Abstract;
using SportsStore.Entities;
using System.Data.Linq;
using System.Linq;

    namespace SportsStore.Concrete
    {
        public class SqlProductsRepository : IProductRepository
        {
            private Table<Product> productsTable;

            public SqlProductsRepository(string connnectionString)
            {
                productsTable = (new DataContext(connnectionString)).GetTable<Product>();
            }

            public IQueryable<Product> Products
            {
                get { return productsTable; }
            }
        }

    }

Basically, I get this:

base {System.SystemException} = {“Specified cast is not valid.”}

This implies the cast is invalid

update
My database looks like that:

>

 **ProductID  int (primary key) Name  
     nvarchar(100) Description  
 nvarchar(500) Category  
 nvarchar(50) Price  int**

StackTrace:

[InvalidCastException: Specified cast is not valid.]
System.Data.SqlClient.SqlBuffer.get_Decimal() +274
System.Data.SqlClient.SqlDataReader.GetDecimal(Int32 i) +44
Read_Product(ObjectMaterializer1 ) +1088
System.Data.Linq.SqlClient.ObjectReader2.MoveNext() +32
System.Collections.Generic.List1..ctor(IEnumerable1 collection) +406
System.Linq.Enumerable.ToList(IEnumerable1 source) +58
SportsStore.Controllers.ProductController.List() in
D:\Call.of.Duty.Modern.Warfare.3-RELOADED\SportsStore\SportsStore\SportsStore\Controllers\ProductController.cs:28
lambda_method(Closure , ControllerBase , Object[] ) +96
System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase
controller, Object[] parameters) +51
System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext
controllerContext, IDictionary2 parameters) +409
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext
controllerContext, ActionDescriptor actionDescriptor, IDictionary2
parameters) +52
System.Web.Mvc.<>c__DisplayClassd.<InvokeActionMethodWithFilters>b__a()
+127 System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter
filter, ActionExecutingContext preContext, Func1 continuation) +436
System.Web.Mvc.<>c_DisplayClassf.b_c()
+61 System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext
controllerContext, IList1 filters, ActionDescriptor actionDescriptor,
IDictionary2 parameters) +305
System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext
controllerContext, String actionName) +830
System.Web.Mvc.Controller.ExecuteCore() +136
System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext)
+111 System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext
requestContext) +39
System.Web.Mvc.<>c_DisplayClass8.b_4() +65
System.Web.Mvc.Async.<>c_DisplayClass1.b_0() +44
System.Web.Mvc.Async.<>c__DisplayClass81.<BeginSynchronous>b__7(IAsyncResult
_) +42 System.Web.Mvc.Async.WrappedAsyncResult1.End() +141 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult,
Object tag) +54
System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult,
Object tag) +40
System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult)
+52 System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult
result) +38
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
+8966925 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +184

Answer 1

Your error message states that the value for the Price column cannot be converted to a decimal.

You need to make sure that your database table has the correct column type for the Price column and that it contains valid data.

Also, if your column in the database allows NULL values, you need to map it to a nullable decimal with decimal? Price { get; set; }