Question

我显示组成产品的项目库存，用户必须能够在选择产品后在DataGridView中为每个项目更新这些项目的大小和数量。

我创建DataGridViews和事件以允许以编程方式更新数据库，因为每个产品最多可以包含1个项目（最多5个项目）。

SqlCommand stockCommand;
SqlDataAdapter stockAdapter;
SqlCommandBuilder stockBuilder;
DataSet stockDs;
DataTable stockTable;

private void DisplayItems()
{
    string queryItems = "SELECT id_item, id_PF, Name, Type FROM Items WHERE id_PF = "+ PF_id + " AND Type = 'BE'";
    using (SqlConnection con = new SqlConnection(conStringLocal))
    {
        using (SqlCommand cmdStock = new SqlCommand(queryItems, con))
        {
        int i = 0;
        con.Open();
        SqlDataReader readerStock = cmdStock.ExecuteReader();

        while (readerStock.Read())
        {
            string itemName = readerStock["Name"].ToString();
        DisplayItemsStock(i, itemName);
        i++;
        }
    }
    }
}


private void DisplayItemsStock(int i, string item)
{
    DataGridView stock = new DataGridView();
    stock.KeyDown += new KeyEventHandler(stock_KeyDown);

    string queryItemStock = "SELECT id_stock, item_name, size, quantity FROM Stock WHERE item_name = '" + item + "'";
    SqlConnection con = new SqlConnection(conStringLocal);
    stockCommand = new SqlCommand(queryItemStock con);
    stockAdapter = new SqlDataAdapter(stockCommand);
    stockBuilder = new SqlCommandBuilder(stockAdapter);
    stockDs = new DataSet();
    stockAdapter.Fill(stockDs, "stock");
    stockTable = stockDs.Tables["stock"];
    con.Close();
    stock.DataSource = stockTable;

    panelStock.Controls.Add(stock);
}

private void stock_KeyDown(object sender, KeyEventArgs e)
{
    DataGridView stock = (DataGridView)sender;

    if (e.Keycode == Keys.Enter)
    {
    // Check different conditions and update if everything is good

    using (SqlConnection con = new SqlConnection(conStringLocal))
        {
        con.Open();
        stockAdapter.Update(stockTable);
        MessageBox.Show("Saved changes");
    }       
    }
}

仅当我需要在所有最后创建的DataGridView上运行Update命令时，才发生更新命令。

Answer 1

我相信您会遇到此问题，因为这些变量在navigator.mediaDevices.getUserMedia({ audio: { deviceId: devices[0].deviceId } });之间共享。

DataGridViews

例如，当为第一个项目创建SqlCommand stockCommand; SqlDataAdapter stockAdapter; SqlCommandBuilder stockBuilder; DataSet stockDs; DataTable stockTable;时，使用对该项目的查询将DataGridView设置为新的stockCommand。适配器，构建器，数据集和表也由此创建。为下一项创建SqlCommand时，就会出现问题。现在，将使用下一个项目的查询创建一个新的DataGridView对象。同样，将适配器，构建器，数据集和表都设置为下一项的新对象。他们不再使用查询的第一项。

现在，当按键事件发生时，它会使用stockCommand和stockTable来查询最后一项。因此，最后一项是唯一更新的项。

您可以通过为每个stockAdapter创建并保留单独的命令，适配器，构建器，数据集和数据表变量来避免此问题。您可以使用DataGridView来做到这一点，或者我可以使用新的类来做到这一点。

Dictionary

public class StockItem { private const string conStringLocal = "Data Source=TestDatabase.sqlite;Version=3;"; private readonly SqlCommand stockCommand; private readonly SqlDataAdapter stockAdapter; private readonly SqlCommandBuilder stockBuilder; private readonly DataSet stockDs; private readonly DataTable stockTable; public DataGridView StockDataGridView { get; } public StockItem(string item) { StockDataGridView = new DataGridView(); StockDataGridView.KeyDown += new KeyEventHandler(stock_KeyDown); string queryItemStock = "SELECT id_stock, item_name, size, quantity " + "FROM Stock WHERE item_name = '" + item + "'"; SqlConnection con = new SqlConnection(conStringLocal); stockCommand = new SqlCommand(queryItemStock, con); stockAdapter = new SqlDataAdapter(stockCommand); stockBuilder = new SqlCommandBuilder(stockAdapter); stockDs = new DataSet(); stockAdapter.Fill(stockDs, "Stock"); stockTable = stockDs.Tables["Stock"]; con.Close(); StockDataGridView.DataSource = stockTable; } private void stock_KeyDown(object sender, KeyEventArgs e) { DataGridView stock = (DataGridView)sender; if (e.KeyCode == Keys.Enter) { // Check different conditions and update if everything is good using (SqlConnection con = new SqlConnection(conStringLocal)) { con.Open(); stockAdapter.Update(stockTable); MessageBox.Show("Saved changes"); } } } }函数保持不变。 DisplayItems变为：

DisplayItemsStock

使用添加到以编程方式创建的几个控件中的事件

1 个答案: