Receving this error when trying to display specific data from database to datagridview

Question

It works fine when i select all the data from the database and display it. But when i want to specifically display certain data from the database, that error would show up. (System.Data.OleDb.OleDbException: 'No value given for one or more required parameters.' )

  private void button1_Click(object sender, EventArgs e)
  {
   string selectoledb = "Select * from items where Categories=Fitems";
   command = new OleDbCommand(selectoledb, connection);
   da = new OleDbDataAdapter(command);

    DataTable table = new DataTable();
    itemstxt.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill;
    itemstxt.RowTemplate.Height = 120;
    itemstxt.AllowUserToAddRows = false;

    da.Fill(table);

    itemstxt.DataSource = table;

    DataGridViewImageColumn imageColumn = new DataGridViewImageColumn();
    imageColumn = (DataGridViewImageColumn)itemstxt.Columns[3];
    imageColumn.ImageLayout = DataGridViewImageCellLayout.Stretch;

     DataGridViewButtonColumn button = new DataGridViewButtonColumn();
     button.HeaderText = "Buttons";
     button.Name = "button";
     button.Text = "Add to cart";
     button.UseColumnTextForButtonValue = true;
     itemstxt.Columns.Add(button);


     da.Dispose();

    }

Answer 1

you need to add parameter to your select

string selectoledb = "Select * from items where Categories=@Fitems";
command.Parameters.Add("@Fitems", SqlDbType.Varchar).Value = Fitems.Text; //or value you want to filter