Question

What’s wrong with my code? This code is from my VB .NET program which I converted to C# but gets an error.. It is used to to SELECT data from database with the use of LIKE for searching.. Here is my code:

public void byItemCode(ListView LV, String SearchBox)
        {
            try
            {
                con.Open();

                ds.Tables.Add(dt);
                OleDbDataAdapter da = new OleDbDataAdapter("SELECT ItemCode, Title, Genre, Film, YearReleased, Classification, NumberOfDiscs FROM tblDVDInventory WHERE ItemCode LIKE '%" + SearchBox + "%' ORDER BY Title", con);
                da.Fill(dt);

                int num = 1;

                for (int ctr = 0; ctr <= dt.Rows.Count - 1; ctr++)
                {
                    ListViewItem Item = new ListViewItem();
                    Item.Text = num;
                    Item.SubItems.Add(dt.Rows[ctr]["ItemCode"]);
                    Item.SubItems.Add(dt.Rows[ctr]["Title"]);
                    Item.SubItems.Add(dt.Rows[ctr]["Genre"]);
                    Item.SubItems.Add(dt.Rows[ctr]["Film"]);
                    Item.SubItems.Add(dt.Rows[ctr]["YearReleased"]);
                    Item.SubItems.Add(dt.Rows[ctr]["Classification"]);
                    Item.SubItems.Add(dt.Rows[ctr]["NumberOfDiscs"]);
                    LV.Items.Add(Item);

                    num = num + 1;
                }

                con.Close();
            }
            catch (Exception error)
            {
                MessageBox.Show(error.ToString());
            }
        }

and then on the Search Form, here is the code:

var Search = new SearchMethods();

                if (cmbSearchBy.Text == "Item Code")
                {
                    lvwInventory.Items.Clear();
                    Search.byItemCode(lvwInventory, txtSearch.Text);
                }

I wonder how to do this the right way in C#? Thanks.

Answer 1

Your Datatable will be filled with Objects, not strings. ListView wants strings, so you need to call ToString() or typecast to string type. Use ToString() if you don’t know what types to expect or if you don’t expect strings; use (string) casting if you expect a string.