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db.savechanges（）不起作用(db.savechanges() is not working)

编程入门 行业动态 更新时间:2024-10-21 04:04:02
db.savechanges（）不起作用(db.savechanges() is not working)

我正在学习如何使用实体框架创建Master-Details Windows窗体，但如果我修改了某列或添加了新行，则db.Savechanges()不起作用。 根据这个视频教程，它会工作，但它不会。

Product_Form.cs

using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Forms; namespace RemoteSynchronizer { public partial class Product : Form { ProductsEntities db = new ProductsEntities(); public Product() { InitializeComponent(); } private void Product_Form_Load(object sender, EventArgs e) { product_DBindingSource.DataSource = db.Product_D.ToList(); } private void bindingNavigatorAddNewItem_Click(object sender, EventArgs e) { } private void product_DBindingNavigatorSaveItem_Click(object sender, EventArgs e) { // Product_D obj = new Product_D(); // obj.PCode = pCodeTextBox.Text; // obj.Name = nameTextBox.Text; // obj.Batch = batchTextBox.Text; // obj.Expiry = expiryTextBox.Text; // obj.Price = priceTextBox.Text; //try // { // Product_D temp = db.Product_D.Single(t => t.PCode == pCodeTextBox.Text); // MessageBox.Show("Product Exists"); // } // catch // { // db.Product_D.Add(obj); db.SaveChanges(); //} } private void bindingNavigatorDeleteItem_Click(object sender, EventArgs e) { } } }

当我尝试在代码中使用注释方法时，它提供了一个错误

错误 

************** Exception Text **************
System.Data.Entity.Infrastructure.DbUpdateException: Unable to update the EntitySet 'Product_D' because it has a DefiningQuery and no <InsertFunction> element exists in the <ModificationFunctionMapping> element to support the current operation. ---> System.Data.UpdateException: Unable to update the EntitySet 'Product_D' because it has a DefiningQuery and no <InsertFunction> element exists in the <ModificationFunctionMapping> element to support the current operation.
   at System.Data.SqlClient.SqlGen.DmlSqlGenerator.ExpressionTranslator.Visit(DbScanExpression expression)
   at System.Data.Common.CommandTrees.DbScanExpression.Accept(DbExpressionVisitor visitor)
   at System.Data.SqlClient.SqlGen.DmlSqlGenerator.GenerateInsertSql(DbInsertCommandTree tree, SqlVersion sqlVersion, List`1& parameters)
   at System.Data.SqlClient.SqlGen.SqlGenerator.GenerateSql(DbCommandTree tree, SqlVersion sqlVersion, List`1& parameters, CommandType& commandType, HashSet`1& paramsToForceNonUnicode)
   at System.Data.SqlClient.SqlProviderServices.CreateCommand(DbProviderManifest providerManifest, DbCommandTree commandTree)
   at System.Data.SqlClient.SqlProviderServices.CreateCommand(DbCommandTree commandTree)
   at System.Data.Mapping.Update.Internal.UpdateTranslator.CreateCommand(DbModificationCommandTree commandTree)
   at System.Data.Mapping.Update.Internal.DynamicUpdateCommand.CreateCommand(UpdateTranslator translator, Dictionary`2 identifierValues)
   at System.Data.Mapping.Update.Internal.DynamicUpdateCommand.Execute(UpdateTranslator translator, EntityConnection connection, Dictionary`2 identifierValues, List`1 generatedValues)
   at System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter)
   at System.Data.EntityClient.EntityAdapter.Update(IEntityStateManager entityCache)
   at System.Data.Objects.ObjectContext.SaveChanges(SaveOptions options)
   at System.Data.Entity.Internal.InternalContext.SaveChanges()
   --- End of inner exception stack trace ---
   at System.Data.Entity.Internal.InternalContext.SaveChanges()
   at System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
   at System.Data.Entity.DbContext.SaveChanges()
   at RemoteSynchronizer.Product.product_DBindingNavigatorSaveItem_Click(Object sender, EventArgs e) in e:\Study\Project\RemoteSynchronizer\RemoteSynchronizer\Product_Form.cs:line 50
   at System.Windows.Forms.ToolStripItem.RaiseEvent(Object key, EventArgs e)
   at System.Windows.Forms.ToolStripButton.OnClick(EventArgs e)
   at System.Windows.Forms.ToolStripItem.HandleClick(EventArgs e)
   at System.Windows.Forms.ToolStripItem.HandleMouseUp(MouseEventArgs e)
   at System.Windows.Forms.ToolStripItem.FireEventInteractive(EventArgs e, ToolStripItemEventType met)
   at System.Windows.Forms.ToolStripItem.FireEvent(EventArgs e, ToolStripItemEventType met)
   at System.Windows.Forms.ToolStrip.OnMouseUp(MouseEventArgs mea)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.ToolStrip.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.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)


************** Loaded Assemblies **************
mscorlib
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.18010 built by: FX45RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.NET/Framework/v4.0.30319/mscorlib.dll
----------------------------------------
RemoteSynchronizer
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///E:/Study/Project/RemoteSynchronizer/RemoteSynchronizer/bin/Debug/RemoteSynchronizer.exe
----------------------------------------
System.Windows.Forms
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Windows.Forms/v4.0_4.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System.Drawing
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Drawing/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------
System
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.18016 built by: FX45RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System/v4.0_4.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Configuration
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Configuration/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
----------------------------------------
System.Xml
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
System.Web
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_32/System.Web/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Web.dll
----------------------------------------
System.Core
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Core/v4.0_4.0.0.0__b77a5c561934e089/System.Core.dll
----------------------------------------
EntityFramework
    Assembly Version: 5.0.0.0
    Win32 Version: 5.0.20627.0
    CodeBase: file:///E:/Study/Project/RemoteSynchronizer/RemoteSynchronizer/bin/Debug/EntityFramework.DLL
----------------------------------------
System.Data.Entity
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Data.Entity/v4.0_4.0.0.0__b77a5c561934e089/System.Data.Entity.dll
----------------------------------------
Anonymously Hosted DynamicMethods Assembly
    Assembly Version: 0.0.0.0
    Win32 Version: 4.0.30319.18010 built by: FX45RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_32/mscorlib/v4.0_4.0.0.0__b77a5c561934e089/mscorlib.dll
----------------------------------------
Accessibility
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/Accessibility/v4.0_4.0.0.0__b03f5f7f11d50a3a/Accessibility.dll
----------------------------------------
System.Data
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_32/System.Data/v4.0_4.0.0.0__b77a5c561934e089/System.Data.dll
----------------------------------------
System.Transactions
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_32/System.Transactions/v4.0_4.0.0.0__b77a5c561934e089/System.Transactions.dll
----------------------------------------
System.Numerics
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Numerics/v4.0_4.0.0.0__b77a5c561934e089/System.Numerics.dll
----------------------------------------
System.Data.OracleClient
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_32/System.Data.OracleClient/v4.0_4.0.0.0__b77a5c561934e089/System.Data.OracleClient.dll
----------------------------------------
System.Xml.Linq
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Xml.Linq/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.Linq.dll
----------------------------------------
System.EnterpriseServices
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_32/System.EnterpriseServices/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.EnterpriseServices.dll
----------------------------------------
EntityFrameworkDynamicProxies-RemoteSynchronizer
    Assembly Version: 1.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Data.Entity/v4.0_4.0.0.0__b77a5c561934e089/System.Data.Entity.dll
----------------------------------------
System.Runtime.Serialization
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Runtime.Serialization/v4.0_4.0.0.0__b77a5c561934e089/System.Runtime.Serialization.dll
----------------------------------------
System.ComponentModel.DataAnnotations
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.ComponentModel.DataAnnotations/v4.0_4.0.0.0__31bf3856ad364e35/System.ComponentModel.DataAnnotations.dll
----------------------------------------
Microsoft.SqlServer.Types
    Assembly Version: 11.0.0.0
    Win32 Version: 2011.0110.2100.060 ((SQL11_RTM).120210-1917 )
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/Microsoft.SqlServer.Types/11.0.0.0__89845dcd8080cc91/Microsoft.SqlServer.Types.dll
----------------------------------------

************** JIT Debugging **************
To enable just-in-time (JIT) debugging, the .config file for this
application or computer (machine.config) must have the
jitDebugging value set in the system.windows.forms section.
The application must also be compiled with debugging
enabled.

For example:

<configuration>
    <system.windows.forms jitDebugging="true" />
</configuration>

When JIT debugging is enabled, any unhandled exception
will be sent to the JIT debugger registered on the computer
rather than be handled by this dialog box.
 

 如何摆脱这个问题？ 我试图解决这个简单的方法db.savechanges()但它不会工作。 
I'm following this tutorial Creating Master-Details Windows Forms with the Entity Framework but the db.Savechanges() isn't working if I modified some column or add a new row. According to this video tutorial it will work but it doesn't.
 

Product_Form.cs
 
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace RemoteSynchronizer
{
    public partial class Product : Form
    {

        ProductsEntities db = new ProductsEntities();
        public Product()
        {
            InitializeComponent();
        }

        private void Product_Form_Load(object sender, EventArgs e)
        {
            product_DBindingSource.DataSource = db.Product_D.ToList();
        }

        private void bindingNavigatorAddNewItem_Click(object sender, EventArgs e)
        {

        }

        private void product_DBindingNavigatorSaveItem_Click(object sender, EventArgs e)
        {
            // Product_D obj = new Product_D();
            // obj.PCode = pCodeTextBox.Text;
            // obj.Name = nameTextBox.Text;
            // obj.Batch = batchTextBox.Text;
            // obj.Expiry = expiryTextBox.Text;
            // obj.Price = priceTextBox.Text;

            //try
            // {
            //     Product_D temp = db.Product_D.Single(t => t.PCode == pCodeTextBox.Text);

            //     MessageBox.Show("Product Exists");
            // }
            // catch 
            // {
            //     db.Product_D.Add(obj);
                 db.SaveChanges();

             //}

        }

        private void bindingNavigatorDeleteItem_Click(object sender, EventArgs e)
        {

        }

    }
}
 

When I try to use comment method in code it gives an error
 

Error
 

************** Exception Text **************
System.Data.Entity.Infrastructure.DbUpdateException: Unable to update the EntitySet 'Product_D' because it has a DefiningQuery and no <InsertFunction> element exists in the <ModificationFunctionMapping> element to support the current operation. ---> System.Data.UpdateException: Unable to update the EntitySet 'Product_D' because it has a DefiningQuery and no <InsertFunction> element exists in the <ModificationFunctionMapping> element to support the current operation.
   at System.Data.SqlClient.SqlGen.DmlSqlGenerator.ExpressionTranslator.Visit(DbScanExpression expression)
   at System.Data.Common.CommandTrees.DbScanExpression.Accept(DbExpressionVisitor visitor)
   at System.Data.SqlClient.SqlGen.DmlSqlGenerator.GenerateInsertSql(DbInsertCommandTree tree, SqlVersion sqlVersion, List`1& parameters)
   at System.Data.SqlClient.SqlGen.SqlGenerator.GenerateSql(DbCommandTree tree, SqlVersion sqlVersion, List`1& parameters, CommandType& commandType, HashSet`1& paramsToForceNonUnicode)
   at System.Data.SqlClient.SqlProviderServices.CreateCommand(DbProviderManifest providerManifest, DbCommandTree commandTree)
   at System.Data.SqlClient.SqlProviderServices.CreateCommand(DbCommandTree commandTree)
   at System.Data.Mapping.Update.Internal.UpdateTranslator.CreateCommand(DbModificationCommandTree commandTree)
   at System.Data.Mapping.Update.Internal.DynamicUpdateCommand.CreateCommand(UpdateTranslator translator, Dictionary`2 identifierValues)
   at System.Data.Mapping.Update.Internal.DynamicUpdateCommand.Execute(UpdateTranslator translator, EntityConnection connection, Dictionary`2 identifierValues, List`1 generatedValues)
   at System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter)
   at System.Data.EntityClient.EntityAdapter.Update(IEntityStateManager entityCache)
   at System.Data.Objects.ObjectContext.SaveChanges(SaveOptions options)
   at System.Data.Entity.Internal.InternalContext.SaveChanges()
   --- End of inner exception stack trace ---
   at System.Data.Entity.Internal.InternalContext.SaveChanges()
   at System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
   at System.Data.Entity.DbContext.SaveChanges()
   at RemoteSynchronizer.Product.product_DBindingNavigatorSaveItem_Click(Object sender, EventArgs e) in e:\Study\Project\RemoteSynchronizer\RemoteSynchronizer\Product_Form.cs:line 50
   at System.Windows.Forms.ToolStripItem.RaiseEvent(Object key, EventArgs e)
   at System.Windows.Forms.ToolStripButton.OnClick(EventArgs e)
   at System.Windows.Forms.ToolStripItem.HandleClick(EventArgs e)
   at System.Windows.Forms.ToolStripItem.HandleMouseUp(MouseEventArgs e)
   at System.Windows.Forms.ToolStripItem.FireEventInteractive(EventArgs e, ToolStripItemEventType met)
   at System.Windows.Forms.ToolStripItem.FireEvent(EventArgs e, ToolStripItemEventType met)
   at System.Windows.Forms.ToolStrip.OnMouseUp(MouseEventArgs mea)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.ToolStrip.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.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)


************** Loaded Assemblies **************
mscorlib
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.18010 built by: FX45RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.NET/Framework/v4.0.30319/mscorlib.dll
----------------------------------------
RemoteSynchronizer
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///E:/Study/Project/RemoteSynchronizer/RemoteSynchronizer/bin/Debug/RemoteSynchronizer.exe
----------------------------------------
System.Windows.Forms
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Windows.Forms/v4.0_4.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System.Drawing
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Drawing/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------
System
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.18016 built by: FX45RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System/v4.0_4.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Configuration
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Configuration/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
----------------------------------------
System.Xml
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
System.Web
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_32/System.Web/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Web.dll
----------------------------------------
System.Core
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Core/v4.0_4.0.0.0__b77a5c561934e089/System.Core.dll
----------------------------------------
EntityFramework
    Assembly Version: 5.0.0.0
    Win32 Version: 5.0.20627.0
    CodeBase: file:///E:/Study/Project/RemoteSynchronizer/RemoteSynchronizer/bin/Debug/EntityFramework.DLL
----------------------------------------
System.Data.Entity
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Data.Entity/v4.0_4.0.0.0__b77a5c561934e089/System.Data.Entity.dll
----------------------------------------
Anonymously Hosted DynamicMethods Assembly
    Assembly Version: 0.0.0.0
    Win32 Version: 4.0.30319.18010 built by: FX45RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_32/mscorlib/v4.0_4.0.0.0__b77a5c561934e089/mscorlib.dll
----------------------------------------
Accessibility
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/Accessibility/v4.0_4.0.0.0__b03f5f7f11d50a3a/Accessibility.dll
----------------------------------------
System.Data
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_32/System.Data/v4.0_4.0.0.0__b77a5c561934e089/System.Data.dll
----------------------------------------
System.Transactions
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_32/System.Transactions/v4.0_4.0.0.0__b77a5c561934e089/System.Transactions.dll
----------------------------------------
System.Numerics
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Numerics/v4.0_4.0.0.0__b77a5c561934e089/System.Numerics.dll
----------------------------------------
System.Data.OracleClient
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_32/System.Data.OracleClient/v4.0_4.0.0.0__b77a5c561934e089/System.Data.OracleClient.dll
----------------------------------------
System.Xml.Linq
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Xml.Linq/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.Linq.dll
----------------------------------------
System.EnterpriseServices
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_32/System.EnterpriseServices/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.EnterpriseServices.dll
----------------------------------------
EntityFrameworkDynamicProxies-RemoteSynchronizer
    Assembly Version: 1.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Data.Entity/v4.0_4.0.0.0__b77a5c561934e089/System.Data.Entity.dll
----------------------------------------
System.Runtime.Serialization
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Runtime.Serialization/v4.0_4.0.0.0__b77a5c561934e089/System.Runtime.Serialization.dll
----------------------------------------
System.ComponentModel.DataAnnotations
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.17929
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.ComponentModel.DataAnnotations/v4.0_4.0.0.0__31bf3856ad364e35/System.ComponentModel.DataAnnotations.dll
----------------------------------------
Microsoft.SqlServer.Types
    Assembly Version: 11.0.0.0
    Win32 Version: 2011.0110.2100.060 ((SQL11_RTM).120210-1917 )
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/Microsoft.SqlServer.Types/11.0.0.0__89845dcd8080cc91/Microsoft.SqlServer.Types.dll
----------------------------------------

************** JIT Debugging **************
To enable just-in-time (JIT) debugging, the .config file for this
application or computer (machine.config) must have the
jitDebugging value set in the system.windows.forms section.
The application must also be compiled with debugging
enabled.

For example:

<configuration>
    <system.windows.forms jitDebugging="true" />
</configuration>

When JIT debugging is enabled, any unhandled exception
will be sent to the JIT debugger registered on the computer
rather than be handled by this dialog box.
 

How to get rid of this problem? I'm trying to solve this by simple method db.savechanges() but it won't work.

                
最满意答案

                
                    
                        
 
 
 无法更新EntitySet，因为它具有DefiningQuery，并且元素中不存在元素以支持当前操作。 
 

 

 确保你的表有一个主键 ！ 
 

 如果不添加主键并更新实体框架模型并再次运行。 
 

 资源： 
 
 
Unable to update the EntitySet because it has a DefiningQuery and no element exists in the element to support the current operation.
 

 

Make sure that your table has a primary key ! 
 

If not add the primary key and update the Entity Framework model and run again.
 

Source:

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