如何在访问数据库与 2 个日期之间进行搜索？

Question

我正在尝试此代码，但它在 da.Fill(dt) 上显示错误

No value given for one or more required parameters.

为什么会显示该错误？我清楚地检查了所有数据库、表和字段的名称，它们都是正确的，并且我使用日期/时间字段作为日期时间。

你能帮我解决这个问题吗？

     string conn = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\ahmed\OneDrive\Documents\shop.accdb";
       OleDbConnection ccc = new OleDbConnection(conn);
        ccc.Open();
        string css = "SELECT * from tbl3 Where dateitem between '" + dateTimePicker1.Value.ToString() + "%' AND '" + dateTimePicker2.Value.ToString()+"%'";
        OleDbCommand non = new OleDbCommand(css, ccc);
        OleDbDataAdapter da = new OleDbDataAdapter(non);
        DataTable dt = new DataTable();
        da.Fill(dt);
        count = Convert.ToInt32(dt.Rows.Count.ToString());
        dataGridView1.DataSource = new BindingSource(dt, null);

Answer 1

正如其他人所提到的，您应该使用参数而不是硬编码值。

using (OleDbConnection conn = new OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\ahmed\OneDrive\Documents\shop.accdb"))
{
    conn.Open();
    // DbCommand also implements IDisposable
    using (OleDbCommand cmd = conn.CreateCommand())
    {
        var param1 = new OleDbParameter("@DateTimePicker1", OleDbType.DBDate); //you may have to play with different types
        param1.Value = dateTimePicker1.Value;
        cmd.Parameters.Add(param1);

        var param2 = new OleDbParameter("@DateTimePicker2", OleDbType.DBDate);
        param2.Value = dateTimePicker2.Value;
        cmd.Parameters.Add(param2);

        cmd.CommandText = "SELECT * from tbl3 Where datetime >= @DateTimePicker1 and datetime <= @DateTimePicker2";

        OleDbDataAdapter da = new OleDbDataAdapter(cmd);
        DataTable dt = new DataTable();
        da.Fill(dt);
        count = Convert.ToInt32(dt.Rows.Count.ToString());
        dataGridView1.DataSource = new BindingSource(dt, null);
    }
}