C# dlused.Context.SubmitChanges（）中发生了一些情况……我尝试了，将代码更改为：dlu.QuestionID=matchedques；收到以下消息：错误：无法将类型“System.Linq.IQueryable”隐式转换为“Syst

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dlused.Context.SubmitChanges（）中发生了一些情况……我尝试了，将代码更改为：dlu.QuestionID=matchedques；收到以下消息：错误：无法将类型“System.Linq.IQueryable”隐式转换为“System.Guid”C:\Documents and SahGilbert-请参阅下面的我的答案如果您投了反对票，请指定原因。这个答案有什么问题？

public static void GetQuesID(string quesText)
    {
        ExamineDataContext dc = new ExamineDataContext();
        var matchedques = from q in dc.GetTable<Question>()
                            where q.QuestionText.Contains(quesText)
                            select new{
                                q.QuestionID
                            };
        foreach (var element in matchedques)
        {
            MessageBox.Show(element.ToString());
        }

        try
        {
            Guid g = Guid.NewGuid();
            Table<DateLastUsed> dlused = Repository.GetDateLastUsedTable();
            DateLastUsed dlu = new DateLastUsed(); ;
            string qidGuidString = matchedques.ToString();
            Guid convQuesGuid = new Guid(qidGuidString);
            dlu.DLUID = g;
            dlu.QuestionID = convQuesGuid;
            dlu.DateLastUsed1 = DateTime.Now;

            dlused.InsertOnSubmit(dlu);
            dlused.Context.SubmitChanges();
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

var matchedques = from q in dc.GetTable<Question>()
                            where q.QuestionText.Contains(quesText)
                            select q.QuestionID;

foreach (var element in matchedques)
{
    MessageBox.Show(element.ToString());
}

var matchedques = from q in dc.GetTable<Question>()
                            where q.QuestionText.Contains(quesText)
                            select new{
                                theID = q.QuestionID
                            };

foreach (var element in matchedques)
{
    MessageBox.Show(element.theID.ToString());
}

string qidGuidString = matchedques.ToString();

string qidGuidString = matchedques.Single().ToString();

var matchedques = from q in dc.GetTable<Question>()
                            where q.QuestionText.Contains(quesText)
                            select new DateLastUsed() {
                                DLUID = Guid.NewGuid(),
                                QuestionID = q.QuestionID,
                                DateLastUsed1 = DateTime.Now
                            };

Table<DateLastUsed> dlused = Repository.GetDateLastUsedTable();

foreach(var dlu in matchedques)
{
    dlused.InsertOnSubmit(dlu);
    dlused.Context.SubmitChanges();
}

...
var matchedques = from q in dc.GetTable<Question>()
                        where q.QuestionText.Contains(quesText)
                        select q.QuestionID;

var matchedques = from q in dc.GetTable<Question>()
                            where q.QuestionText.Contains(quesText)
                            select new{
                                q.QuestionID
                            };

string qidGuidString = matchedques.ToString();

var matchedQuesId = 
    dc.GetTable<Question>()
    .Where(q =>q.QuestionText.Contains(quesText))
    .Single()
    .QuestionID;

var matchedques = (from q in dc.GetTable<Question>()
                  where q.QuestionText.Contains(quesText)
                  select new{
                      q.QuestionID
                  }).FirstOrDefault();

if (matchedques != null){
    // Just use matchedques.QuestionID to get your value
}