C＃SQLITE指定的转换无效

Question

尝试从SQLite数据库中检索数据时出现错误“ 指定的转换无效”。

认为它与DeviceRecord.ip_address有关。ToString认为sqlite不喜欢它，有人可以帮忙吗？

我是编码和SQLite的新手，所以希望所有这一切都有意义，我的代码可能遍地都是，很抱歉...

来自浏览器的错误消息

[InvalidCastException: Specified cast is not valid.]
   System.Data.SQLite.SQLiteDataReader.VerifyType(Int32 i, DbType typ) +327
   System.Data.SQLite.SQLiteDataReader.GetBoolean(Int32 i) +263
   System.Data.Entity.Core.Objects.Internal.ShapedBufferedDataRecord.Initialize(DbDataReader reader, DbSpatialDataReader spatialDataReader, Type[] columnTypes, Boolean[] nullableColumns) +420
   System.Data.Entity.Core.Objects.Internal.BufferedDataReader.Initialize(String providerManifestToken, DbProviderServices providerServices, Type[] columnTypes, Boolean[] nullableColumns) +156
   System.Data.Entity.Core.Objects.Internal.ObjectQueryExecutionPlan.Execute(ObjectContext context, ObjectParameterCollection parameterValues) +1014
   System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction(Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess) +512
   System.Data.Entity.Core.Objects.<>c__DisplayClassb.<GetResults>b__9() +203
   System.Data.Entity.Core.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption) +341
   System.Data.Entity.Core.Objects.ObjectQuery`1.<System.Collections.Generic.IEnumerable<T>.GetEnumerator>b__0() +38
   System.Lazy`1.CreateValue() +727
   System.Lazy`1.LazyInitValue() +184
   System.Data.Entity.Internal.LazyEnumerator`1.MoveNext() +15
   System.Linq.Enumerable.SingleOrDefault(IEnumerable`1 source) +202
   _Default.getIP() +982
   System.Web.UI.Control.OnLoad(EventArgs e) +103
   System.Web.UI.Control.LoadRecursive() +68
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1381

C＃代码

using System;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Net;
using System.Net.Mail;
using System.Text;
using System.Configuration;
using System.Windows;
using System.Net.Sockets;


public partial class _Default : System.Web.UI.Page
{
    string serviceDesk = "email address";
    string emailSubject = "MyPc";
    string IPaddr = "";
    string deviceName = "";
    private readonly object reader;

    public DateTime DateStamp { get; private set; }


    protected void Page_Load(object sender, EventArgs e)
    {
        getIP();
    }

    protected void getIP()
    {
        if (HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDER_FOR"] != null)
        {
            IPaddr = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDER_FOR"].ToString();
        }
        if (HttpContext.Current.Request.UserHostAddress.Length != 0)
        {
            IPaddr = HttpContext.Current.Request.UserHostAddress;            
            DateStamp = DateTime.Now;

            try
            {
                deviceName = Dns.GetHostEntry(IPAddress.Parse(IPaddr)).HostName;
            }
            catch (SocketException)
            {
                deviceName = "could not be resolved";
            }
        }
        Label1.Text = "IP Address: " + " " + IPaddr;
        Label2.Text = "PC Name: " + " " + deviceName;
        Label3.Text = "Date and Time: " + " " + DateStamp;

        using (mainEntities dbcontent = new mainEntities())
        {
            var DeviceRecord = dbcontent.devices.SingleOrDefault(x => x.ip_address == IPaddr);

            if(DeviceRecord !=null)
            {
                string ipaddress = DeviceRecord.ip_address.ToString();
                string name = DeviceRecord.name.ToString();

                Label4.Text = ipaddress;
                Label5.Text = name;
            }


            }

    }





    private void EmailVerificationRequest(string recepientEmail, string subject)
    {
        try
        {
            using (MailMessage mailMessage = new MailMessage())
            {
                StringBuilder sbEmailBody = new StringBuilder();

                sbEmailBody.Append("IP address " + IPaddr + "<br/>");
                sbEmailBody.Append("Hostname " + " " + deviceName + "<br/>");
                sbEmailBody.Append("Date and Time " + " " + DateStamp);

                mailMessage.From = new MailAddress(ConfigurationManager.AppSettings["FromEmail"]);
                mailMessage.Subject = subject;
                mailMessage.Body = sbEmailBody.ToString();
                mailMessage.IsBodyHtml = true;
                mailMessage.To.Add(new MailAddress(recepientEmail));

                SmtpClient smtp = new SmtpClient();

                smtp.Host = ConfigurationManager.AppSettings["Host"];
                smtp.Port = Convert.ToInt32(ConfigurationManager.AppSettings["Port"]);
                smtp.EnableSsl = Convert.ToBoolean(ConfigurationManager.AppSettings["EnableSsl"]);

                System.Net.NetworkCredential NetworkCred = new System.Net.NetworkCredential();
                NetworkCred.UserName = ConfigurationManager.AppSettings["UserName"];
                NetworkCred.Password = ConfigurationManager.AppSettings["Password"];

                if (string.IsNullOrWhiteSpace(NetworkCred.UserName))
                {
                    smtp.UseDefaultCredentials = true;
                }
                else
                {
                    smtp.Credentials = NetworkCred;
                    smtp.UseDefaultCredentials = false;
                }

                smtp.Port = int.Parse(ConfigurationManager.AppSettings["Port"]);

                try
                {
                    smtp.Send(mailMessage);
                }

                catch (SmtpException e)
                {
                }
            }
        }

        catch
        {
        }
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        EmailVerificationRequest(serviceDesk, emailSubject);
        Response.Redirect("~/message.aspx");
    }


}