Select information from database table

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Hello, i m doing a c# project with ADO .NET data entity model, i have a table Subjects with columns (idSubject(int), nameSubject(nvarchar), subjectNoted(bit/boolean). I'm getting from the table the first subject that have `subjectNoted==false` then i change the value to `==true` after clickin a button with this code:

C#

private void button1_Click(object sender, EventArgs e)
            {
                using (DbEntities db = new DbEntities())
                {
                Subjects firstSubject = db.Subjects.FirstOrDefault(s => s.subjectNoted == false);
                    if (firstSubject != null)
                    {
                        firstSubject.subjectNoted = true;
                        db.SaveChanges();
                        MessageBox.Show("Subject Noted", "OK");                    
                    }
                }
            }
    
            private void button2_Click(object sender, EventArgs e)
            {
        //code to show the next subject that have subjectNoted==false
            }

I have another button, this one must ignore the first subject and show the second one with `subjectNoted==false`. I created a method ShowSubject, but i can't find how to select the second subject that have `subjectNoted==false` and show it with the methode??

C#

private void ShowSubject(Subjects subject)
            {
                using (DbEntities db = new DbEntities())
                {
                   Subjects  firstSubject = db.Subjects.FirstOrDefault(s => s.subjectNoted == false);
                    if (firstSubject != null)
                    {
                        textBox1.Text = firstSubject.nameSubject;
                    }
                }
            }

Someone can help me please i'm stuck here!

Posted 12-May-13 9:23am

Nnorss

Updated 12-May-13 11:10am

v4

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frostfang · Accepted Answer · 2013-05-12T13:31:00

Have you tried using Skip() and Take() methods ?

Skip(n) will jump the n number of records and Take(n) will return n many records.

for example you could try

C#

var subjects = db
    .Subjects
    .Where(s=> s.subjectNoted == false)
    .OrderBy(s=> s.idSubject)
    .Skip(1)
    .Take(1)
    .FirstOrDefault();

One thing is you do need to add an order by to your query before you can do a skip / take.

Masoom Mir · Accepted Answer · 2013-05-14T00:58:00

private void ShowSubject(Subjects subject)
{
using (DbEntities db = new DbEntities())
{
Subjects firstSubject = db.Subjects.FirstOrDefault(s => s.subjectNoted == false).Skip(1).Take(1) .FirstOrDefault();
if (firstSubject != null)
{
textBox1.Text = firstSubject.nameSubject;
}
}
}

Select information from database table

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