CODEWITHSUNDEEP
c#listview
Stefan Gies
Stefan Gies

Reputation: 318

Check of listview contains a specific number

I have the following problem: I want to check if the reservation number already exists in my listview.

I have the following code to add a reservation to the listview.

 reservations.Add(new Reservation(nameTextbox.Text, lastnameTextBox.Text, gendercomboBox.SelectedText, Convert.ToInt32(ageNumericUpDown.Value), Convert.ToInt32(kamercomboBox.SelectedIndex) + 1, Convert.ToInt32(quantityUpDown.Value), true));
 reserveringListView.Items.Clear();
 foreach (Reservation reservation in reservations)
 {
     if (!reserveringListView.Items.Contains(reservation.roomnumber))
     {
         ListViewItem livi = new ListViewItem(reservation.name);
         livi.SubItems.Add(reservation.lastname);
         livi.SubItems.Add(Convert.ToString(reservation.gender));
         livi.SubItems.Add(Convert.ToString(reservation.age));
         livi.SubItems.Add(Convert.ToString(reservation.quantity));
         livi.SubItems.Add(Convert.ToString(reservation.roomnumber));
         reserveringListView.Items.Add(livi);
     }
     else
     {
         MessageBox.Show("Its impossible to reserve")
     }
}

When i try to test this code i get the following error: Cannot convert from int to System.Windows.Forms.ListViewItem

Upvotes: 1

Views: 825

Answers (3)

JohnnyAW
JohnnyAW

Reputation: 2876

List<T>.Contains(docs) method expects an argument of type T (System.Windows.Forms.ListViewItem) in your case. But you try to pass an int to that method. Thats why you get the error.

In your case I would create a HashSet<int> and store reservation.roomnumber in it, so you can look up next time, if the roomnumber is already there.

Example:

reserveringListView.Items.Clear();
HashSet<int> roomCheck = new HashSet<int>();
foreach (Reservation reservation in reservations)
{
    if (roomCheck.Add(reservation.roomnumber))
    {
    ...
    }
}

EDIT: added an example

Upvotes: 0

Roman
Roman

Reputation: 12171

You should change your if statement, because you check if ListView.Items contains int. You can't do this and, also, inside if you add roomnumber as string (but you check if it is in ListView.Items as int). Your if statement should be: 

if (!reserveringListView.Items.Cast<ListViewItem>().Any((i) => i.SubItems[5].Text == Convert.ToString(reservation.roomnumber)))

Maybe I made mistake with index in SubItems. You should check it and if there is mistake write a comment please.

Upvotes: 2

Sjors Ottjes
Sjors Ottjes

Reputation: 1217

You are getting the error because you are giving the .Contains method an int parameter, while it only accepts a ListViewItem as parameter

try something like:

if (!reserveringListView.Items.Any(litem => litem.SubItems[5].Value == reservation.roomnumber))
{

}

Upvotes: 1

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