select single value from linq

Question

I Have a dataTable called dt that filled from Database. the SQL Command is:

SELECT s.keyName,s.value FROM setting as s

after I fill dataTable I want to select a single value from filled dt. So I tried to do some linq that here I show:

if (dtSetting.Rows.Count > 0)
  {
      var r1 = (from r in dtSetting.AsEnumerable()
       where r.Field<string>("keyName") == "logoName"
       select r.Field<string>("value"));

       MessageBox.Show(r1.ToString());
  }

but I can't see the value of s.value and r1.show says that

system.data.enumerableRowCollection`1[system.String]

How can I implement this code to get a real value of the specific column?

Carra · Accepted Answer · 2017-07-31 08:40:41Z

4

Your r1 is an IEnumerable < string >. You should select an item from it.

Example:

   MessageBox.Show(r1.First());

answered Jul 31, 2017 at 8:40

Carra

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Comments

kgzdev · Accepted Answer · 2017-07-31 08:54:26Z

3

r1 variable is IEnumarable, so you can get the value by applying index . You can use First() and ElementAt() too.

 if (r1.Count() > 0)
    MessageBox.Show(r1.ToList()[0].ToString());
    //MessageBox.Show(r1.First());
    //MessageBox.Show(r1.ElementAt(0));

edited Jul 31, 2017 at 8:54

answered Jul 31, 2017 at 8:40

kgzdev

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3 Comments

Carra Over a year ago

You can't use an index on IEnumerable. First casting it to a List would work.

DerApe Over a year ago

ElementAt() would also be possible

Reza Paidar Over a year ago

Thanks, both @Carra and you. I choose your answer because of your better answer. Thanks a lot you saved my time.

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