Giving Multiple List<int> type criteria by using linq in Entity Framework

Question

I am working a project that uses entity framework. I want simple thing when people click to searchLookUpedit button I want to show values filtered according to Companies that exists in Orders. So here is the code:

private void SearchLookUpEdit_Customer_Click(object sender, EventArgs e)
{
    object [] siparisNo = new object[gridView1.RowCount];
    List<Siparisler> siparisList = new List<Siparisler>();
    List<int> firmaIds = new List<int>();

    for (int i = 0; i < gridView1.RowCount; i++)
    {
        siparisNo[i] = gridView1.GetRowCellValue(i,"SiparisNo");
        int sipNo = Convert.ToInt32(siparisNo[i]);
        Siparisler siparis = context.Siparisler.Where(p => p.Id == sipNo).FirstOrDefault();
        siparisList.Add(siparis);
        firmaIds.Add(siparis.Firma_Id);
    }

    for (int i = 0; i < firmaIds.Count; i++)
    {
        int a = firmaIds[i];
        firmalarBindingSource.DataSource = context.Firmalar.Where(p => p.Id == );
    }
}

In here second for loop . Lets imagine that in firmaIds<int> list type have 3 values. And assume that they are 3, 5 and 8 for example, and I want only this 3 Companies will exist in firmalarBindingSource.DataSource after the click event finished running. I tried but it did not. If my criteria were different data type it was easy to filter. Is there anyway to do this?

Answer 1

If I have understood what you are asking try replacing

 for (int i = 0; i < firmaIds.Count; i++)
 {
     int a = firmaIds[i];
     firmalarBindingSource.DataSource = context.Firmalar.Where(p => p.Id == );
 }

with

firmalarBindingSource.DataSource = context.Firmalar.Where(p => firmaIds.Contains(p.Id));

Answer 2

@Faby answered your question, but I just wanted to add that you can also optimize the first part of your code, so you could do everything in two lines of code in a more functional manner using Linq:

IEnumerable<Firmalar> firmalarDataSource = Enumerable.Range(0, gridView1.RowCount - 1)
    .Select((index) =>
    {
        var siparisId = Convert.ToInt32(gridView1.GetRowCellValue(index, "SiparisNo"));
        var siparis = context.Siparisler.FirstOrDefault(p => p.Id == siparisId);
        return context.Firmalar.FirstOrDefault(f => f.Id == siparis.Firma_Id);

    })
    .Distinct();

firmalarBindingSource.DataSource = firmalarDataSource;

Note: these are two lines, but i adjusted the formatting to be more readable ;)

If you value performance over lines of code, here is a three line example with less roundtrips to the DB:

var siparisIds = Enumerable.Range(0, gridView1.RowCount - 1)
    .Select(index => Convert.ToInt32(gridView1.GetRowCellValue(index, "SiparisNo")));

var firmaIds = context.Siparisler.Where(p => siparisIds.Contains(p.Id)).Select(s => s.Firma_Id).Distinct();

firmalarBindingSource.DataSource = context.Firmalar.Where(f => firmaIds.Contains(f.Id));