有没有办法强制LINQ到SQL来对待列脏吗？在全球范围内就足够了......

Is there a way to force LINQ-to-SQL to treat a column as dirty? Globally would suffice....

基本上，我有与遗留系统，我说的就是与L2S一些审计code的一个问题，试想：

Basically, I've got a problem with some audit code on a legacy system that I'm talking to with L2S, imagine:

var ctx = new SomeDataContext(); // disposed etc - keeping it simple for illustration
var cust = ctx.Customers.First(); // just for illustration
cust.SomeRandomProperty = 17; // whatever
cust.LastUpdated = DateTime.UtcNowl;
cust.UpdatedBy = currentUser;
ctx.SubmitChanges(); // uses auto-generated TSQL

这是好的，但如果同一用户更新其连续两次，的 UpdatedBy 是一个NOP，并且TSQL会（大约）：

This is fine, but if the same user updates it twice in a row, the UpdatedBy is a NOP, and the TSQL will be (roughly):

UPDATE [dbo].[Customers]
SET SomeRandomColumn = @p0 , LastUpdated = @p1 -- note no UpdatedBy
WHERE Id = @p2 AND Version = @p3

在我的情况下，问题在于目前还对所有表皮带和撑条审计触发器，它检查是否审核列已被更新，如果不假定开发商有过错（代 SUSER_SNAME（），虽然它可能只是那样容易引发错误）。

In my case, the problem is that there is currently a belt-and-braces audit trigger on all tables, which checks to see if the audit column has been updated, and if not assumes the developer is at fault (substituting SUSER_SNAME(), although it could just as readily throw an error).

我真的很希望能够做的是说随时更新此列，即使是不脏？ - 这是可能的。

What I'd really like to be able to do is say "always update this column, even if it isn't dirty" - is this possible?

推荐答案

根据KristoferA's回答，我结束了东西的喜欢的下方;这是邪恶和脆（反射通常是），但可能有足够的现在。战斗的另一边是改变触发器的行为：

Based on KristoferA's answer, I ended up with something like below; this is evil and brittle (reflection often is), but may have to suffice for now. The other side of the battle is to change the triggers to behave:

partial class MyDataContext // or a base-class
{
    public override void SubmitChanges(System.Data.Linq.ConflictMode failureMode)
    {
        this.MakeUpdatesDirty("UpdatedBy", "Updated_By");
        base.SubmitChanges(failureMode);
    }
}
public static class DataContextExtensions
{
    public static void MakeUpdatesDirty(
        this DataContext dataContext,
        params string[] members)
    {
        if (dataContext == null) throw new ArgumentNullException("dataContext");
        if (members == null) throw new ArgumentNullException("members");
        if (members.Length == 0) return; // nothing to do
        foreach (object instance in dataContext.GetChangeSet().Updates)
        {
            MakeDirty(dataContext, instance, members);
        }
    }
    public static void MakeDirty(
        this DataContext dataContext, object instance ,
        params string[] members)
    {
        if (dataContext == null) throw new ArgumentNullException("dataContext");
        if (instance == null) throw new ArgumentNullException("instance");
        if (members == null) throw new ArgumentNullException("members");
        if (members.Length == 0) return; // nothing to do
        const BindingFlags AllInstance = BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public;
        object commonDataServices = typeof(DataContext)
            .GetField("services", AllInstance)
            .GetValue(dataContext);
        object changeTracker = commonDataServices.GetType()
            .GetProperty("ChangeTracker", AllInstance)
            .GetValue(commonDataServices, null);
        object trackedObject = changeTracker.GetType()
            .GetMethod("GetTrackedObject", AllInstance)
            .Invoke(changeTracker, new object[] { instance });
        var memberCache = trackedObject.GetType()
            .GetField("dirtyMemberCache", AllInstance)
            .GetValue(trackedObject) as BitArray;

        var entityType = instance.GetType();
        var metaType = dataContext.Mapping.GetMetaType(entityType);
        for(int i = 0 ; i < members.Length ; i++) {
            var member = entityType.GetMember(members[i], AllInstance);
            if(member != null && member.Length == 1) {
                var metaMember = metaType.GetDataMember(member[0]);
                if (metaMember != null)
                {
                    memberCache.Set(metaMember.Ordinal, true);
                }
            }
        }
    }
}