列表框项目和所选项目-Java 学习之路

我有一个带有ListBox和Database-class的Form . Form从Database调用一个返回字符串的方法 .

public listItem()
    {
        InitializeComponent();
        Db = new Database();
        itemList = new List<string>();
        showAllItems();
    }

现在，showAllItems-function调用返回List的Db.getAllitems（）函数 .

private void showAllItems()
    {
        itemList = Db.getAllItems();
        lb_itemList.DataSource = itemList;
    }

列表显示列表框中所有项目的名称 . 但是，我还想返回项目的描述 . 但我不希望描述显示在列表框中 . 我希望它显示在listBox旁边的标签上，该标签显示所选项目的描述 .

我的主要问题是，我不知道如何在不显示列表框中的所有数据的情况下返回多个数据 . 我只想要列表框中的名称和标签上列表框旁边显示的其他数据，这取决于ListBox中的选定项目

public List<string> getAllItems()
    {
        List<string> itemList = new List<string>();
        SQLiteConnection connection = new SQLiteConnection("Data Source=HCI.db");
        connection.Open();

        SQLiteCommand cmd = new SQLiteCommand("SELECT rid, name, category, price, status, specific FROM items", connection);
        SQLiteDataReader reader = cmd.ExecuteReader();

        if (reader.HasRows)
        {
            while (reader.Read())
            {
                //itemList.Add(reader.GetString(reader.GetInt64(rid)));
                itemList.Add(reader.GetString(reader.GetOrdinal("name")));
                itemList.Add(reader.GetString(reader.GetOrdinal("category")));
                itemList.Add(reader.GetString(reader.GetOrdinal("price")));
                itemList.Add(reader.GetString(reader.GetOrdinal("status")));
                itemList.Add(reader.GetString(reader.GetOrdinal("specific")));

            }
        }
        connection.Close();
        return itemList;

    }

2 回答

您可以创建包含类的另一个列表，并在列表框中选择项目时从列表中获取项目 .

public class YourClass{
    public int Id { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }
    public string Description { get; set; }
}


public List<YourClass> getAllItems()
{
List<string> itemList = new List<string>();
SQLiteConnection connection = new SQLiteConnection("Data Source=HCI.db");
connection.Open();

SQLiteCommand cmd = new SQLiteCommand("SELECT rid, name, category, price, status, specific FROM items", connection);
SQLiteDataReader reader = cmd.ExecuteReader();

if (reader.HasRows)
{
    while (reader.Read())
    {
        //itemList.Add(reader.GetString(reader.GetInt64(rid)));
        itemList.Add(new YourClass(){
      Id = reader.GetString(reader.GetInt64("Id")),
      Name = reader.GetString(reader.GetOrdinal("name")),
      Description = reader.GetString(reader.GetOrdinal("desc")),
      Price = reader.GetString(reader.GetOrdinal("price"))
});               

    }
}
connection.Close();
return itemList;

}

//in your selectedindexchanged event
private void lb_itemList_SelectedIndexChanged(object sender, EventArgs e)
{
    if (lb_itemList.SelectedIndex > -1)
    {
          var item = lb_itemList.SelectedItem as YouClass;
          if (item != null)
          {
                lblDescription.Text = item.Description;
                lblPrice.Text = item.Price
          }
    }
 }

回复于 2024-05-02T10:39:44+08:00

像这样创建自定义 Class ：

public class Item 
{
     public string Name;
     public string Description;
}

然后改变你的退货方法：

public List<Item> getAllItems()
{
        List<Item> itemList = new List<Item>();
        SQLiteConnection connection = new SQLiteConnection("Data Source=HCI.db");
        connection.Open();

        SQLiteCommand cmd = new SQLiteCommand("SELECT rid, name, category, price, status, specific FROM items", connection);
        SQLiteDataReader reader = cmd.ExecuteReader();

        if (reader.HasRows)
        {
            while (reader.Read())
            {
                //itemList.Add(reader.GetString(reader.GetInt64(rid)));
                var item = new Item();
                item.Name = reader.GetString(reader.GetOrdinal("name"));
                item.Description = reader.GetString(reader.GetOrdinal("specific"))
                itemList.Add(item);
            }
        }
        connection.Close();
        return itemList;
}

并将其绑定到您的列表：

private void showAllItems()
{
        itemList = Db.getAllItems();
        lb_itemList.DisplayMember = "Name";
        lb_itemList.DataSource = itemList;
}

并最后实现 SelectedIndexChanged 事件来处理描述标签：

private void lb_itemList_SelectedIndexChanged(object sender, EventArgs e)
{
        if (lb_itemList.SelectedIndex > -1)
        {
              var item = lb_itemList.SelectedItem as Item;
              if (item != null)
              {
                    lblDescription.Text = item.Description;
              }
        }
}

回复于 2024-05-02T10:39:44+08:00

列表框项目和所选项目

2 回答

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