Question

将EF6 / LINQ与MySQL服务器配合使用。我有一个DataGridView使用DataTable绑定到实体的BindingList。一切正常，甚至删除记录。但我无法插入尚未存在于数据库中的记录。

我的意思是，如果我从数据库中选择一条记录，然后删除它，SaveChanges（），然后重新插入它，它会重新插入它自己！但是，如果我尝试插入前。 new tcompanyaddress（），设置其属性，并插入它？不行。

最终目标是模拟事务清除与DB中的CompanyID FK关联的所有地址，然后只需从BindingList重新插入最新编辑的地址。同样，它有效......但不适用于新条目。

using (JobTrackerEntities context = new JobTrackerEntities())
{
    context.Database.Connection.ConnectionString += ";password=orbitman1;";
    // Update main profile
    tcompany companyRow = context.tcompany.Find(Company.CompanyID);
    companyRow.CompanyName = Company.CompanyName;
    // Update foreign profiles
    var addresses = from address in context.tcompanyaddress // Retreive all addresses that were removed
                    where address.CompanyID == Company.CompanyID
                    select address;
    // Clear existing addresses
    foreach (tcompanyaddress address in addresses)
    {
        Console.WriteLine("Remove " + address.LocationName);
        context.Entry(address).State = EntityState.Deleted;
    }
    addresses = from address in context.tcompanyaddress // Retreive all addresses that were removed
                where address.CompanyID == Company.CompanyID
                select address;
    Console.WriteLine("After clear: " + addresses.Count());
    // Replace with new addresses
    foreach (tcompanyaddress address in CompanyAddresses)
    {
        Console.WriteLine("Add " + address.LocationName);
        context.tcompanyaddress.Add(address);
    }
    // Commit transaction
    context.SaveChanges();
    addresses = from address in context.tcompanyaddress // Retreive all addresses that were removed
                where address.CompanyID == Company.CompanyID
                select address;
    Console.WriteLine("After add: " + addresses.Count());

    RefreshProfileForm();
}

Answer 1

解决方案很简单。当我向BindingList添加一个新地址时，我没有设置CompanyID FK，这意味着查询永远不会选择它。

EF6 / LINQ MySQL - 不会插入

1 个答案: