使用（ling to sql）更新错误 [英] Updating error using (ling to sql)

问题描述

我有两张表，由外键绑定CarrierID：

 运营商[CarrierID，CarrierName] 
 CarrierID = 1，CarrierName = DHL 
 CarrierID = 2，CarrierName = Fedex 
 ... 
供应商[VendorID，VendorName，CarrierID] 
 VendorID = 1，VendorName = D-link，CarrierID = 1 
 VendorID = 2，VendorName = Netbes，CarrierID = 2 
  

当我尝试更新vendorview中的载体名称。我得到这个错误ForeignKeyReferenceAlreadyHasValueException

我有类叫editvendor

  public static void editvendor（Vendor vendor）
 {
 
 using（MyinvoiceDataDataContext connv = new MyinvoiceDataDataContext（））
 {
 
供应商editven = s in connv.Vendors 
其中s.VendorID == vendor.VendorID 
 select s）.FirstOrDefault（）; 
 
 editven.VendorAddress = editven.VendorAddress; 
 editven.VendorBalance = editven.VendorBalance; 
 editven.VendorContactName = editven.VendorContactName; 
 editven.VendorEmail = editven.VendorEmail; 
 editven.VendorFax = editven.VendorFax; 
 editven.VendorName = editven.VendorName; 
 editven.VendorPaymentTerms = editven.VendorPaymentTerms; 
 editven.VendorPhone = editven.VendorPhone; 
 editven.VendorRemark = editven.VendorRemark; 
 editven.VendorTax = editven.VendorTax; 
 editven.VendorWebsite = editven.VendorWebsite; 
 editven.CarrierID = editven.Carrier.CarrierID; 
 connv.SubmitChanges（）; 
 
} 
} 
 #endregion 
  

Windows窗体（编辑供应商表单）我使用这个：

  private void Window_Loaded（object sender，RoutedEventArgs e）
 {
 
 MyinvoiceDataDataContext contecta = new MyinvoiceDataDataContext（）; 
 var tb = from cont in contecta.Carriers 
 select new {s.CarrierID，s.CarrierName}; 
 comVendorCarrier.ItemsSource = tb; 
 comVendorCarrier.DisplayMemberPath =CarrierName; 
 comVendorCarrier.SelectedValuePath =CarrierID; 
 
 ViewVendor vendview = new ViewVendor（）; 
 txtVendorName.Text = vendor.VendorName.Trim（）; 
 txtVendorBalance.Text = vendor.VendorBalance.Trim（）; 
 txtVendorContactName.Text = vendor.VendorContactName.Trim（）; 
 txtVendorPhone.Text = vendor.VendorPhone.Trim（）; 
 txtVendorFax.Text = vendor.VendorTax.Trim（）; 
 txtVendorEmail.Text = vendor.VendorEmail.Trim（）; 
 txtVendorWebsite.Text = vendor.VendorWebsite.Trim（）; 
 txtVendorRemarks.Text = vendor.VendorRemark.Trim（）; 
 txtVendorAddress.Text = vendor.VendorAddress.Trim（）; 
 txtVendorTax.Text = vendor.VendorTax.Trim（）; 
 comVendorCarrier.Text = vendor.Carrier.CarrierName.Trim（）; 
 ComVendorPaymentTerms.Text = vendor.VendorPaymentTerms.Trim（）; 
} 
  

此代码用于保存编辑后的供应商

  private void EditVendorSavebtn_Click_1（object sender，RoutedEventArgs e）
 {
 int SelectedCarrierId = int.Parse（comVendorCarrier.SelectedValue.ToString（） ）; 
 if（txtVendorName.Text.Trim（）==）
 MessageBox.Show（请填写供应商名称）; 
 
 if（txtVendorBalance.Text.Trim（）==）
 MessageBox.Show（请填写供应商的余额）; 
 
 if（txtVendorContactName.Text.Trim（）==）
 MessageBox.Show（请填写供应商的联系人姓名）; 
 
 if（txtVendorPhone.Text.Trim（）==）
 MessageBox.Show（请填写供应商的电话号码）; 
 
 if（txtVendorFax.Text.Trim（）==）
 MessageBox.Show（请填写供应商的传真号码）; 
 
 if（txtVendorEmail.Text.Trim（）==）
 MessageBox.Show（请填写供应商的E-maill）; 
 
 if（txtVendorWebsite.Text.Trim（）==）
 MessageBox.Show（请填写供应商的网站）; 
 
 if（txtVendorAddress.Text.Trim（）==）
 MessageBox.Show（请填写供应商地址）; 
 
 else 
 {
 
 vendor.VendorName = txtVendorName.Text.Trim（）; 
 vendor.VendorBalance = txtVendorBalance.Text.Trim（）; 
 vendor.VendorContactName = txtVendorContactName.Text.Trim（）; 
 vendor.VendorPhone = txtVendorPhone.Text.Trim（）; 
 vendor.VendorFax = txtVendorFax.Text.Trim（）; 
 vendor.VendorEmail = txtVendorEmail.Text.Trim（）; 
 vendor.VendorWebsite = txtVendorWebsite.Text.Trim（）; 
 vendor.VendorRemark = txtVendorRemarks.Text.Trim（）; 
 vendor.VendorAddress = txtVendorAddress.Text.Trim（）; 
 vendor.VendorPaymentTerms = ComVendorPaymentTerms.Text; 
 vendor.CarrierID = SelectedCarrierId; 
 vendor.VendorTax = txtVendorFax.Text.Trim（）; 
 vendorinfo.editvendor（vendor）; 
 MessageBox.Show（vendor.VendorName +成功编辑）; 
 Window_Loaded（null，null）; 
} 
  

解决方案

我期望是这种组合：

  //某处
 comVendorCarrier.Text = vendor.Carrier.CarrierName.Trim（）; 
 ... 
 //其他地方
 vendor.CarrierID = SelectedCarrierId; 
  

一个是使用面向对象的方法，一个是使用基于id的方法 - 但是，如果两者都加载并且不兼容，问题。我想知道你是否应该使用：

  vendor.Carrier = null; 
 vendor.CarrierID = SelectedCarrierId; 
  

那么正是使用哪个载体的一个定义。

或者，单独处理运营商，而不是：

  comVendorCarrier.Text = vendor.Carrier .CarrierName.Trim（）; 
  

使用：

  var carrier = context.Carriers.Single（x => x.Id = vendor.CarrierId）; 
 comVendorCarrier.Text = carrier.CarrierName.Trim（）; 
  

，然后从不加载 vendor.Carrier as一个对象。

I have two tables, binded by foreign key CarrierID:

Carrier[CarrierID,CarrierName] 
CarrierID = 1, CarrierName = DHL
CarrierID = 2, CarrierName = Fedex
...
Vendor[VendorID, VendorName, CarrierID]  
VendorID = 1, VendorName =D-link , CarrierID=1  
VendorID = 2, VendorName = Netbes , CarrierID= 2

When i try to update the carriername in vendorview. Im getting this error "ForeignKeyReferenceAlreadyHasValueException"

I have class called editvendor

public static void editvendor(Vendor vendor)
        {

            using (MyinvoiceDataDataContext connv = new MyinvoiceDataDataContext())
            {

                Vendor editven = (from s in connv.Vendors
                                 where s.VendorID == vendor.VendorID
                                 select s).FirstOrDefault();

                editven.VendorAddress = editven.VendorAddress;
                editven.VendorBalance = editven.VendorBalance;
                editven.VendorContactName = editven.VendorContactName;
                editven.VendorEmail = editven.VendorEmail;
                editven.VendorFax = editven.VendorFax;
                editven.VendorName = editven.VendorName;
                editven.VendorPaymentTerms = editven.VendorPaymentTerms;
                editven.VendorPhone = editven.VendorPhone;
                editven.VendorRemark = editven.VendorRemark;
                editven.VendorTax = editven.VendorTax;
                editven.VendorWebsite = editven.VendorWebsite;
                editven.CarrierID = editven.Carrier.CarrierID;
                connv.SubmitChanges();

            }
        }
        #endregion

In the windows form(edit vendor form) i use this:

 private void Window_Loaded(object sender, RoutedEventArgs e)
        {

            MyinvoiceDataDataContext contecta = new MyinvoiceDataDataContext();
            var tb = from s in contecta.Carriers
                     select new { s.CarrierID, s.CarrierName };
            comVendorCarrier.ItemsSource = tb;
            comVendorCarrier.DisplayMemberPath = "CarrierName";
            comVendorCarrier.SelectedValuePath = "CarrierID";

            ViewVendor vendview = new ViewVendor();
            txtVendorName.Text = vendor.VendorName.Trim();
            txtVendorBalance.Text = vendor.VendorBalance.Trim();
            txtVendorContactName.Text = vendor.VendorContactName.Trim();
            txtVendorPhone.Text = vendor.VendorPhone.Trim();
            txtVendorFax.Text = vendor.VendorTax.Trim();
            txtVendorEmail.Text = vendor.VendorEmail.Trim();
            txtVendorWebsite.Text = vendor.VendorWebsite.Trim();
            txtVendorRemarks.Text = vendor.VendorRemark.Trim();
            txtVendorAddress.Text = vendor.VendorAddress.Trim();
            txtVendorTax.Text = vendor.VendorTax.Trim();
            comVendorCarrier.Text = vendor.Carrier.CarrierName.Trim();
            ComVendorPaymentTerms.Text = vendor.VendorPaymentTerms.Trim();
        }

This code i use to save the edited vendor

 private void EditVendorSavebtn_Click_1(object sender, RoutedEventArgs e)
        {
            int SelectedCarrierId = int.Parse(comVendorCarrier.SelectedValue.ToString());
            if (txtVendorName.Text.Trim() == "")
                MessageBox.Show("Please fill vendor's Name");

            if (txtVendorBalance.Text.Trim() == "")
                MessageBox.Show("Please fill vendor's balance");

            if (txtVendorContactName.Text.Trim() == "")
                MessageBox.Show("Please fill vendor's contact name");

            if (txtVendorPhone.Text.Trim() == "")
                MessageBox.Show("Please fill vendor's phone number");

            if (txtVendorFax.Text.Trim() == "")
                MessageBox.Show("Please fill vendor's fax number");

            if (txtVendorEmail.Text.Trim() == "")
                MessageBox.Show("Please fill vendor's E-maill");

            if (txtVendorWebsite.Text.Trim() == "")
                MessageBox.Show("Please fill vendor's Website");

            if (txtVendorAddress.Text.Trim() == "")
                MessageBox.Show("Please fill vendor's address");

            else
            {

                vendor.VendorName = txtVendorName.Text.Trim();
                vendor.VendorBalance = txtVendorBalance.Text.Trim();
                vendor.VendorContactName = txtVendorContactName.Text.Trim();
                vendor.VendorPhone = txtVendorPhone.Text.Trim();
                vendor.VendorFax = txtVendorFax.Text.Trim();
                vendor.VendorEmail = txtVendorEmail.Text.Trim();
                vendor.VendorWebsite = txtVendorWebsite.Text.Trim();
                vendor.VendorRemark = txtVendorRemarks.Text.Trim();
                vendor.VendorAddress = txtVendorAddress.Text.Trim();
                vendor.VendorPaymentTerms = ComVendorPaymentTerms.Text;
                vendor.CarrierID = SelectedCarrierId;
                vendor.VendorTax = txtVendorFax.Text.Trim();
                vendorinfo.editvendor(vendor);
                MessageBox.Show(vendor.VendorName + " succesfully edited.");
                Window_Loaded(null, null);
            }

解决方案

I expect it is this combination:

// somewhere
comVendorCarrier.Text = vendor.Carrier.CarrierName.Trim();
...
// somewhere else
vendor.CarrierID = SelectedCarrierId;

One is using the object-oriented approach, one is using the id-based approach - however, if both are loaded and are incompatible, problems. I wonder if you should use:

vendor.Carrier = null;
vendor.CarrierID = SelectedCarrierId;

then there is exactly one definition of which carrier to use.

Alternatively, handle the carrier separately, for example, instead of:

comVendorCarrier.Text = vendor.Carrier.CarrierName.Trim();

use:

var carrier  = context.Carriers.Single(x => x.Id = vendor.CarrierId);
comVendorCarrier.Text = carrier.CarrierName.Trim();

which then never loads vendor.Carrier as an object.

这篇关于使用（ling to sql）更新错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！