Specified cast is not valid C# Entity Framework

Question

Hi I have been getting this Specified cast is not valid in my code but when I connect to my backup database I do not get the Specified cast is not valid error. I am not sure what is going on.

Again, this code works perfectly on one database and gives me the error on the other.

My Controller

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Data.Linq.SqlClient;
using System.Text.RegularExpressions;
using MvcPaging;
using lookups.Models;
using lookups.Helpers;


namespace lookups.Controllers
{
public class MPController : Controller
{
    // GET: /Lookups/
    public LpAppsDataDataContext db = new LpAppsDataDataContext();
    public const int DefaultPageSize = 30;


    //get MP Data
         if (countSpace == 1 && v.Count(char.IsLetter) > 3)
                            {
                                if (SqlString.CheckStringForComma(v))
                                {
                                    mpq = db.mps
                                         .Where(c => c.NAME_LAST.ToLower().Contains(SqlString.GetSplitCommaString(v.ToLower(), 0))).OrderBy(c => c.NAME_LAST).ThenBy(f => f.NAME_FIRST);
                                }
                                else
                                {
                                    mpq = db.mps
                                       .Where(c => c.NAME_LAST.ToLower().Contains(SqlString.GetSplitString(v.ToLower(), 1)) || c.NAME_LAST.Contains(SqlString.GetSplitString(v.ToLower(), 0))).OrderBy(c => c.NAME_LAST).ThenBy(f => f.NAME_FIRST);
                                }
                            }
                            else
                            {
                                mpq = db.mps
                                       .Where(c => c.NAME_L
                ViewBag.count = mpq.Count();
            }
        }
        else { ViewBag.count = 0; }
        @ViewBag.col = "Unclaimed Pensions";

        return View(mpq.ToPagedList(currentPageIndex, DefaultPageSize));
    }

}
}

My Model

[global::System.Data.Linq.Mapping.TableAttribute(Name = "dbo.mp")]
public partial class mp
{

    private string _COMPANY;

    private string _STATE;

    private System.Nullable<System.DateTime> _DOPT;

    private string _SP_STATE;

    private string _PRT_NAME;

    private string _NAME_LAST;

    private string _NAME_FIRST;

    private string _LASTADDRESS;

    private System.Nullable<double> _ID;

    private System.Nullable<System.DateTime> _DATE;

    private string _PLAN_TYPE;

    public mp()
    {
    }

    [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_COMPANY", DbType = "NVarChar(255)")]
    public string COMPANY
    {
        get
        {
            return this._COMPANY;
        }
        set
        {
            if ((this._COMPANY != value))
            {
                this._COMPANY = value;
            }
        }
    }

    [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_STATE", DbType = "NVarChar(255)")]
    public string STATE
    {
        get
        {
            return this._STATE;
        }
        set
        {
            if ((this._STATE != value))
            {
                this._STATE = value;
            }
        }
    }

    [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_DOPT", DbType = "DateTime")]
    public System.Nullable<System.DateTime> DOPT
    {
        get
        {
            return this._DOPT;
        }
        set
        {
            if ((this._DOPT != value))
            {
                this._DOPT = value;
            }
        }
    }

    [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_SP_STATE", DbType = "NVarChar(255)")]
    public string SP_STATE
    {
        get
        {
            return this._SP_STATE;
        }
        set
        {
            if ((this._SP_STATE != value))
            {
                this._SP_STATE = value;
            }
        }
    }

    [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_PRT_NAME", DbType = "NVarChar(255)")]
    public string PRT_NAME
    {
        get
        {
            return this._PRT_NAME;
        }
        set
        {
            if ((this._PRT_NAME != value))
            {
                this._PRT_NAME = value;
            }
        }
    }

    [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_NAME_LAST", DbType = "NVarChar(255)")]
    public string NAME_LAST
    {
        get
        {
            return this._NAME_LAST;
        }
        set
        {
            if ((this._NAME_LAST != value))
            {
                this._NAME_LAST = value;
            }
        }
    }

    [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_NAME_FIRST", DbType = "NVarChar(255)")]
    public string NAME_FIRST
    {
        get
        {
            return this._NAME_FIRST;
        }
        set
        {
            if ((this._NAME_FIRST != value))
            {
                this._NAME_FIRST = value;
            }
        }
    }

    [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_LASTADDRESS", DbType = "NVarChar(255)")]
    public string LASTADDRESS
    {
        get
        {
            return this._LASTADDRESS;
        }
        set
        {
            if ((this._LASTADDRESS != value))
            {
                this._LASTADDRESS = value;
            }
        }
    }

    [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_ID", DbType = "Float")]
    public System.Nullable<double> ID
    {
        get
        {
            return this._ID;
        }
        set
        {
            if ((this._ID != value))
            {
                this._ID = value;
            }
        }
    }

    [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_DATE", DbType = "DateTime")]
    public System.Nullable<System.DateTime> DATE
    {
        get
        {
            return this._DATE;
        }
        set
        {
            if ((this._DATE != value))
            {
                this._DATE = value;
            }
        }
    }

    [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_PLAN_TYPE", DbType = "NVarChar(255)")]
    public string PLAN_TYPE
    {
        get
        {
            return this._PLAN_TYPE;
        }
        set
        {
            if ((this._PLAN_TYPE != value))
            {
                this._PLAN_TYPE = value;
            }
        }
    }
}

StackTrace

Line 257:            @ViewBag.col = "Unclaimed Pensions";
Line 258:
Line 259:            return View(mpq.ToPagedList(currentPageIndex,      DefaultPageSize));
Line 260:        }
Line 261:

Stack Trace: 


[InvalidCastException: Specified cast is not valid.]
 System.Data.SqlClient.SqlBuffer.get_Double() +51
System.Data.SqlClient.SqlDataReader.GetDouble(Int32 i) +62
 Read_mp(ObjectMaterializer`1 ) +2057
 System.Data.Linq.SqlClient.ObjectReader`2.MoveNext() +32
   System.Collections.Generic.List`1.InsertRange(Int32 index, IEnumerable`1 collection) +392
   System.Collections.Generic.List`1.AddRange(IEnumerable`1 collection) +10
   MvcPaging.PagedList`1..ctor(IQueryable`1 source, Int32 index, Int32    pageSize, Nullable`1 totalCount) +2014
   MvcPaging.PagingExtensions.ToPagedList(IQueryable`1 source, Int32 pageIndex, Int32 pageSize, Nullable`1 totalCount) +134
   lookups.Controllers.MPController.Mp(Nullable`1 page, String sortOrder) in 

Answer 1

Compare the backup database with the database that doesn't work, specifically the ID column. Make sure they match both the Type (Float) and ability to be Nullable (NULL).

The exception being thrown indicates that one of the columns (that is of type "double") doesn't match the model.

The ID column on the "mp" table is the only double column in your model.

Answer 2

In SQL Server Developer 2019, I used the sys tables to create a SQL script to determine what SQL Server thinks are the types per columns.

select
    obj.name as [Table]
    , col.name as [Column]
    , case
        when type.[precision] > 0 and type.scale = 0 then type.name + '(' + CONVERT(nvarchar(8), type.precision) + ')'
        when type.[precision] > 0 and type.scale > 0 then type.name + '(' + CONVERT(nvarchar(8), type.precision) + ',' + CONVERT(nvarchar(8), type.scale) + ')'
        else type.name end as [FullType]
from
    sys.objects as [obj]
    inner join sys.columns as [col]
        on obj.object_id = col.object_id
    inner JOIN sys.types as [type]
        on col.system_type_id = type.system_type_id
where 
    obj.type = N'U'

I could then use script in a common table expressions (CTE) or other similar structure to filter on specific columns.