Perché Entity Framework genera un cast non valido

Question

Perché Entity Framework genera un cast non valido

.net c# casting entity-framework entity-framework-core

Domanda

Indipendentemente dal metodo che utilizzo per eseguire query sui dati, non riesco a superare questo metodo. Emette sempre un errore:

Il cast specificato non è valido.

Non sono sicuro del motivo per cui questo sta impazzendo sul casting. La colonna è definita come INT(10) in MySQL, il modello è un INT sull'attributo ID , la variabile di input è un INT , eppure c'è ancora un errore di cast! L'uso quasi identico della stessa logica per creare, eliminare e getAllCustomer metodi getAllCustomer funziona getAllCustomer . Questo è l'unico problema.

Ecco il metodo in questione:

public static bool UpdateCustomerById(int id, string updatedName, int updatedAddressId)
{
        try
        {
            using (Context db = new Context())
            {
                Customer customer = (Customer)db.Find(typeof(Customer),id);
                //Customer customer = db.Customer.Find(id);
                customer.AddressId = updatedAddressId;
                customer.CustomerName = updatedName;
                db.SaveChanges();
            }

            return true;
        }
        catch (Exception err)
        {
            Console.WriteLine("Error: " + err);
            throw new Exception("Couldn't update the customer because: " + err);
        }
}

Modello:

using System;
using System.Collections.Generic;

namespace Scheduler.Data.Models
{
    public partial class Customer
    {
        public int CustomerId { get; set; }
        public string CustomerName { get; set; }
        public int AddressId { get; set; }
        public sbyte Active { get; set; }
        public DateTime CreateDate { get; set; }
        public string CreatedBy { get; set; }
        public DateTime LastUpdate { get; set; }
        public string LastUpdateBy { get; set; }
    }
}

Rappresentazione della tabella HTML della tabella del database

<table border=1>
<tr>
<td bgcolor=silver class='medium'>Field</td>
<td bgcolor=silver class='medium'>Type</td>
<td bgcolor=silver class='medium'>Null</td>
<td bgcolor=silver class='medium'>Key</td>
<td bgcolor=silver class='medium'>Default</td>
<td bgcolor=silver class='medium'>Extra</td>
</tr>

<tr>
<td class='normal' valign='top'>customerId</td>
<td class='normal' valign='top'>int(10)</td>
<td class='normal' valign='top'>NO</td>
<td class='normal' valign='top'>PRI</td>
<td class='normal' valign='top'>NULL</td>
<td class='normal' valign='top'></td>
</tr>

<tr>
<td class='normal' valign='top'>customerName</td>
<td class='normal' valign='top'>varchar(45)</td>
<td class='normal' valign='top'>NO</td>
<td class='normal' valign='top'></td>
<td class='normal' valign='top'>NULL</td>
<td class='normal' valign='top'></td>
</tr>

<tr>
<td class='normal' valign='top'>addressId</td>
<td class='normal' valign='top'>int(10)</td>
<td class='normal' valign='top'>NO</td>
<td class='normal' valign='top'></td>
<td class='normal' valign='top'>NULL</td>
<td class='normal' valign='top'></td>
</tr>

<tr>
<td class='normal' valign='top'>active</td>
<td class='normal' valign='top'>tinyint(1)</td>
<td class='normal' valign='top'>NO</td>
<td class='normal' valign='top'></td>
<td class='normal' valign='top'>NULL</td>
<td class='normal' valign='top'></td>
</tr>

<tr>
<td class='normal' valign='top'>createDate</td>
<td class='normal' valign='top'>datetime</td>
<td class='normal' valign='top'>NO</td>
<td class='normal' valign='top'></td>
<td class='normal' valign='top'>NULL</td>
<td class='normal' valign='top'></td>
</tr>

<tr>
<td class='normal' valign='top'>createdBy</td>
<td class='normal' valign='top'>varchar(40)</td>
<td class='normal' valign='top'>NO</td>
<td class='normal' valign='top'></td>
<td class='normal' valign='top'>NULL</td>
<td class='normal' valign='top'></td>
</tr>

<tr>
<td class='normal' valign='top'>lastUpdate</td>
<td class='normal' valign='top'>timestamp</td>
<td class='normal' valign='top'>NO</td>
<td class='normal' valign='top'></td>
<td class='normal' valign='top'>CURRENT_TIMESTAMP</td>
<td class='normal' valign='top'>on update CURRENT_TIMESTAMP</td>
</tr>

<tr>
<td class='normal' valign='top'>lastUpdateBy</td>
<td class='normal' valign='top'>varchar(40)</td>
<td class='normal' valign='top'>NO</td>
<td class='normal' valign='top'></td>
<td class='normal' valign='top'>NULL</td>
<td class='normal' valign='top'></td>
</tr>
</table>

traccia errore:

System.Exception
HResult=0x80131500
Message=couldn't update the customer because: System.InvalidCastException: Specified cast is not valid.
at MySql.Data.MySqlClient.MySqlDataReader.GetFieldValue[T](Int32 ordinal)
at lambda_method(Closure , DbDataReader )
at Microsoft.EntityFrameworkCore.Storage.Internal.TypedRelationalValueBufferFactory.Create(DbDataReader dataReader)
at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.BufferlessMoveNext(DbContext _, Boolean
buffer)
at Pomelo.EntityFrameworkCore.MySql.Storage.Internal.MySqlExecutionStrategy.Execute[TState,TResult](TState state, Func`3
operation, Func`3 verifySucceeded)
at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.MoveNext()
at System.Linq.Enumerable.First[TSource](IEnumerable`1 source)
at lambda_method(Closure )
at Microsoft.EntityFrameworkCore.Query.Internal.LinqOperatorProvider.ResultEnumerable`1.GetEnumerator()
at Microsoft.EntityFrameworkCore.Query.Internal.LinqOperatorProvider.<_TrackEntities>d__17`2.MoveNext()
    at
Microsoft.EntityFrameworkCore.Query.Internal.LinqOperatorProvider.ExceptionInterceptor`1.EnumeratorExceptionInterceptor.MoveNext()
at System.Linq.Enumerable.First[TSource](IEnumerable`1 source)
at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.<>c__DisplayClass15_1`1.<CompileQueryCore>
        b__0(QueryContext qc)
        at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.Execute[TResult](Expression query)
        at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.Execute[TResult](Expression expression)
        at System.Linq.Queryable.First[TSource](IQueryable`1 source, Expression`1 predicate)
        at Scheduler.Data.CustomerDao.UpdateCustomerById(Int32 id, String updatedName, Int32 updatedAddressId)
        Source=Scheduler.Data
        StackTrace:
        at Scheduler.Data.CustomerDao.UpdateCustomerById(Int32 id, String updatedName, Int32 updatedAddressId) in
        C:\Users\source\repos\Scheduler\Scheduler.Data\CustomerDao.cs:line 79
        at Scheduler.Dashboard.ApplyChangesButton_Click(Object sender, EventArgs e) in
        C:\Users\source\repos\Scheduler\Scheduler\Dashboard.cs:line 112
        at System.Windows.Forms.Control.OnClick(EventArgs e)
        at System.Windows.Forms.Button.OnClick(EventArgs e)
        at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
        at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
        at System.Windows.Forms.Control.WndProc(Message& m)
        at System.Windows.Forms.ButtonBase.WndProc(Message& m)
        at System.Windows.Forms.Button.WndProc(Message& m)
        at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
        at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
        at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr
        lparam)
        at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
        at
        System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr
        dwComponentID, Int32 reason, Int32 pvLoopData)
        at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext
        context)
        at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
        at System.Windows.Forms.Application.Run(Form mainForm)
        at Scheduler.Program.Main() in C:\Users\source\repos\Scheduler\Scheduler\Program.cs:line 19

Qualsiasi pensiero o difetto evidente sul perché questo metodo in particolare non funziona sarebbe fantastico, grazie

CoderLee

Vedi di più su Stack Overflow

CoderLee · Accepted Answer · 12/31/2019 6:05:15 PM

La soluzione che ho riscontrato a questo problema era aggiornare il tinyint (1) in un tinyint (3). La modifica che ha risolto gli errori di casting in quanto il framework di entità è stato in grado di lavorare con esso come previsto. Il gotcha è nella CLI che lo rende un tinyint (1) per impostazione predefinita, quindi aggiornandolo in un tinyint (3) dopo che il fatto dovrebbe risolverlo.

Perché Entity Framework genera un cast non valido

Domanda

Fastest Entity Framework Extensions

Risposta accettata

Performance

Expression Evaluator

Related