使用entityframework时，“设置值”不会更新现有行。

问题描述

为什么setvalues对我不起作用？它对模型对象不起作用吗？

Why setvalues is not working for me? Does it not work for model objects?

using (var connection = new TReportEntitiesConnection())
        {

            var header = connection.THeaders.Include("TReports").SingleOrDefault(f => f.ID == model.ID);

            if (header != null)
            {
                header.THeaderTitle = model.THeaderTitle; //update parent
            }
            foreach (var existingChild in header.TReports.ToList())
            {

                if (!model.TReports.Any(c => c.ID == existingChild.ID))
                    connection.TReport.Remove(existingChild);

            }
            foreach (var url in model.TReports)
            {
                var existingChild = header.TReports
                    .Where(c => c.ID == url.ID)
                    .SingleOrDefault();


                if (existingChild!= null)
                { //update child
                    connection.Entry(existingChild).CurrentValues.SetValues(url);
                }
                else
                {
                    var newChild = new TReport
                    {
                        TReportName = url.name,
                        URL = url.url,
                    };

                    header.TReports.Add(newChild);
                }
            }
            connection.SaveChanges();
        }

我尝试过：



我尝试将其更改为但后来我意识到它不断添加新行。

What I have tried:

I tried changing it to but then I realized it is keep adding new rows.

header.TReports.Add(new TReport()
                       {
                           TReportName=url.name,
                           URL=url.url

                       });

推荐答案

existingChild.property = value;
connection.Entrry(existingChild).State = EntityState.Modified;

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