Question

我正在使用C＃解决方案，并且我已经使用DataTable对象填充了我的txtbox，然后检索了行号的信息，问题是，我有导航按钮，下一个和上一个，我只是注意到当我将我的函数调用到PopulateView（）;按下此按钮后，我重做数据库连接，SQLite查询和数据表填充。

我感到惭愧但是，我真的不知道放置此功能的适当位置在哪里，以便我在此表单中的其他功能接收这些对象。

我的代码：

namespace X_Project{
public partial class Cad_Prod : Form
{
    System.Data.SQLite.SQLiteConnection conn1 = new System.Data.SQLite.SQLiteConnection("data source=X.s3db");
    int prodstart = 0;
    public Cad_Prod()
    {
        InitializeComponent();
    }

    public void Cad_Prod_Load(object sender, EventArgs e)
    {

    }

    private void PopulateView()
    {
        string query = "SELECT * FROM Cad_Prod";
        string query2 = "SELECT * FROM Cat";
        try
        {
            using (SQLiteCommand comm = new SQLiteCommand(query, conn1))
            using (SQLiteDataAdapter adapter = new SQLiteDataAdapter(comm))
            using (SQLiteCommand comm2 = new SQLiteCommand(query2, conn1))
            using (SQLiteDataAdapter adapter2 = new SQLiteDataAdapter(comm2))
            {
                conn1.Open();
                DataTable produtos = new DataTable();
                adapter.Fill(produtos);
                DataTable categoria = new DataTable();
                adapter2.Fill(categoria);

                int auxCat = int.Parse(produtos.Rows[prodstart].ItemArray[4].ToString()) - 1;

                txtProdutoNome.Text = produtos.Rows[prodstart].ItemArray[1].ToString();
                txtProdutoPreco.Text = produtos.Rows[prodstart].ItemArray[2].ToString();
                txtProdutoQtd.Text = produtos.Rows[prodstart].ItemArray[3].ToString();
                cbbCategoria.Text = categoria.Rows[auxCat].ItemArray[1].ToString();
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(this, ex.Message, "Erro", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
    }

    private void btnAvancar_Click(object sender, EventArgs e)
    {
        prodstart = prodstart + 1;
        PopulateView();
    }

    private void btnVoltar_Click(object sender, EventArgs e)
    {
        prodstart = prodstart - 1;
        PopulateView();
    }
}

上面的代码有效，但没有我想要的方式，我真正想做的是：

namespace X_Project\
{

public partial class Cad_Prod : Form
    {

    System.Data.SQLite.SQLiteConnection conn1 = new System.Data.SQLite.SQLiteConnection("data source=X.s3db");
    int prodstart = 0;
    public Cad_Prod()
    {
        InitializeComponent();
    }

    public void Cad_Prod_Load(object sender, EventArgs e)
    {

        string query = "SELECT * FROM Cad_Prod";
        string query2 = "SELECT * FROM Cat";
        try
        {
            using (SQLiteCommand comm = new SQLiteCommand(query, conn1))
            using (SQLiteDataAdapter adapter = new SQLiteDataAdapter(comm))
            using (SQLiteCommand comm2 = new SQLiteCommand(query2, conn1))
            using (SQLiteDataAdapter adapter2 = new SQLiteDataAdapter(comm2))
                {
                conn1.Open();
                DataTable produtos = new DataTable();
                adapter.Fill(produtos); // I would like this to be inherited
                DataTable categoria = new DataTable();
                adapter2.Fill(categoria); // I would like this to be inherited
                }
        }
        catch (Exception ex)
        {
            MessageBox.Show(this, ex.Message, "Erro", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }

    private void PopulateView()
    {


                int auxCat = int.Parse(produtos.Rows[prodstart].ItemArray[4].ToString()) - 1;

                txtProdutoNome.Text = produtos.Rows[prodstart].ItemArray[1].ToString();
                txtProdutoPreco.Text = produtos.Rows[prodstart].ItemArray[2].ToString();
                txtProdutoQtd.Text = produtos.Rows[prodstart].ItemArray[3].ToString();
                cbbCategoria.Text = categoria.Rows[auxCat].ItemArray[1].ToString();

    }

    private void btnAvancar_Click(object sender, EventArgs e)
    {
        prodstart = prodstart + 1;
        PopulateView();
    }

    private void btnVoltar_Click(object sender, EventArgs e)
    {
        prodstart = prodstart - 1;
        PopulateView();
    }
}

Answer 1

将dataTable放在使用＆＃34; Lazy初始化程序＆＃34;的表单级属性变量中。模式，即它们被编码的位置，因此它们只调用数据库一次，并用第一次的数据表填充静态私有变量;每次连续调用都会读取私有变量并跳过数据库调用。

conftest.py

继承Datatable对象

1 个答案: