Cannot convert datetime to string

Question

I have a database with some dates, i want to fetch them and convert them into a string[] to use in a graph.

        var Yaxis = db.Graphs
                    .Where(x => x.Node.Contains(Node))
                    .Select(x => x.Dates)
                    .ToArray();


        var data = new string[Yaxis.Length];
        for (int i = 0; i < Yaxis.Length ; i++)
        {
            data[i] = Yaxis[i].ToString;
        }

The .ToString do not work here with a "non-delegate type"-error. I dont know any other way to parse the array to a string[].

Any idea?

ToString is not a delegate, "ToString()" is a method :)

Davut Gürbüz
– Davut Gürbüz

2013-02-13 06:52:47 +00:00
Commented Feb 13, 2013 at 6:52 — Davut Gürbüz
– Davut Gürbüz, Commented Feb 13, 2013 at 6:52

antonijn · Accepted Answer · 2013-02-13 06:57:42Z

4

data[i] = Yaxis[i].ToString();

When you don't include the parentheses, the compiler will assume you're talking about the function ToString, when you're actually talking about the return value.

When you're talking about the function itself, it's called a delegate (kind of similar to a function pointer in C/C++), which explains the error you're getting.

edited Feb 13, 2013 at 6:57

answered Feb 13, 2013 at 6:50

antonijn

5,7702 gold badges29 silver badges33 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

antonijn Over a year ago

@Habib No, it exactly addresses the problem. Look at the last three characters.

Jon Skeet Over a year ago

@Habib: No it's not - the brackets are missing in the question. That's the important bit, although Antonijn should include text explaining it.

platon Over a year ago

@Habib, this answer contains parenthesis for the ToString() method. So, the answer is correct ....

Habib Over a year ago

oh yes, my bad :) but you should have added the details as well +1

Tim Over a year ago

Thank you Antonijn, sometimes you stare yourself dumb on the code :)

Jon Skeet · Accepted Answer · 2013-02-13 06:53:26Z

As Antonijn posted, the immediate problem is that you're using ToString without actually calling the method.

However, you can do better than this to start with by doing it in LINQ:

var data = db.Graphs
             .Where(x => x.Node.Contains(Node))
             .Select(x => x.Dates.ToString())
             .ToArray();

Note that we're calling ToString() in the projection here. If that doesn't give the result you want (e.g. because it performs the conversion in the database) you can split it into two Select calls, with an AsEnumerable call forcing the second one to execute locally:

var data = db.Graphs
             .Where(x => x.Node.Contains(Node))
             .Select(x => x.Dates)
             .AsEnumerable()
             .Select(x => x.ToString())
             .ToArray();

This will use the default string representation of DateTime in the current culture, of course. You may want to consider specifying a standard or custom date/time format string to change the output format, and maybe even a different culture... it depends on what you're going to do with the data.

All of this assumes that you don't need Yaxis for anything else. If you do need Yaxis, you can still use LINQ to simplify your code:

var data = Yaxis.Select(x => x.ToString()).ToArray();

Collectives™ on Stack Overflow

Cannot convert datetime to string

2 Answers 2

5 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

5 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related