小编Nic*_*els的帖子

例如:

Html.TextBoxFor(x => x.ModelProperty)

如果我要将这样的表达式作为方法参数,我将如何从表达式中获取引用的属性？我对表达式的体验有点受限,根据我的知识,我不知道它是如何工作的.

让我们假设以下代码处理DataContext的SaveChanges事件

void Context_SavingChanges(object sender, EventArgs e)
    {

        IEnumerable<ObjectStateEntry> objectStateEntries =
            from ose in this.ObjectStateManager.GetObjectStateEntries(EntityState.Added | EntityState.Modified | EntityState.Deleted)
            where ose.Entity != null
            select ose;

        foreach (ObjectStateEntry entry in objectStateEntries)
        {
            foreach (var field in entry.CurrentValues.DataRecordInfo.FieldMetadata)
            {
                var guid = Guid.NewGuid();
                AuditEntry audit = AuditEntry.CreateAuditEntry(
                    id: guid,
                    entitySet: entry.EntitySet.Name,
                    typeName: entry.Entity.GetType().Name,
                    entityId: (entry.CurrentValues["Id"] as string) ?? ((entry.State == EntityState.Added) ? "New" : null),
                    oldValue: (entry.State != EntityState.Added) ? entry.OriginalValues[field.FieldType.Name].ToString() : "New",
                    newValue: (entry.State != EntityState.Deleted) ? entry.CurrentValues[field.FieldType.Name].ToString() : "Deleted",
                    modifier: Environment.UserDomainName …