指定的强制类型转换无效的C＃实体框架

Question

嗨，我一直在代码中看到这个指定的转换无效，但是当我连接到备份数据库时，我没有收到指定的转换无效的错误。我不确定发生了什么。

同样，此代码可在一个数据库上完美运行，而在另一个数据库上却给我错误。

我的控制器

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));
    }

}
}

我的模特

[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;
            }
        }
    }
}

堆栈跟踪

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

将备份数据库与无效数据库进行比较，尤其是将ID列进行比较。确保它们同时匹配 类型 （浮点数）和可为 空 （NULL）的能力。

引发异常表示列之一（类型为“ double”）与模型不匹配。

“ mp”表上的ID列是模型中唯一的双列。