c# - 删除查询不起作用 SQL C#

Question

我一直在尝试从表中删除行，但我编写的代码不起作用，我不确定这是 SQL 语法还是代码本身，Visual Studio 不会抛出任何错误，它只是启动该程序没有任何问题，在我单击删除按钮后，该程序卡住，我什至无法关闭它。如果我在执行此操作后检查数据库，它保持不变。

另外，如果我解释得不好，我很抱歉，英语不是我的母语，所以对我来说有点困难，提前谢谢你。

      private void button1_Click(object sender, EventArgs e)
    {
        MessageBox.Show("DOING STUFF");
        bool check = true;
        do
        {
            string connectionString = @"Data Source=.\wintouch;Initial Catalog=bbl;User ID=sa;Password=Pa$$w0rd";
            string queryString = string.Empty;
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();
                queryString = "DELETE FROM wgcdoccab WHERE serie ='1' tipodoc ='FSS' AND and contribuinte ='999999990' and  datadoc = CONVERT(varchar(10),(dateadd(dd, -2, getdate())),120) ";                    
                SqlCommand command = new SqlCommand(queryString, connection);
                //command.Connection.Open();
                command.ExecuteNonQuery();

            }
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();
                queryString = "SELECT * FROM wgcdoccab WHERE serie ='1' tipodoc ='FSS' AND and contribuinte ='999999990' and  datadoc = CONVERT(varchar(10),(dateadd(dd, -2, getdate())),120) ";

                using (SqlCommand command = new SqlCommand(queryString, connection))
                using (SqlDataReader reader = command.ExecuteReader())
                {
                    if (reader.HasRows)
                    {
                        check = true;
                    }
                    else
                    {
                        check = false;
                        MessageBox.Show("STILL DOING STUFF");
                    }
                    command.Connection.Close();
                }
            }
        }
        while (check);

Answer 1

我不确定您认为 SQL 命令是如何工作的，但它们肯定不是异步的，因此您既不需要循环也不需要第二个 using block 来检查您刚刚删除的行仍然在那里。只有删除所有行后，删除过程才会结束。

此外，您发布的代码不可能是真正的代码，因为您应该由于 WHERE 子句中的语法无效而收到 SQL 异常。

因此您的代码可以缩短为以下内容(也修复 WHERE 子句):

private void button1_Click(object sender, EventArgs e)
{
    MessageBox.Show("DOING STUFF");

        string connectionString = @"Data Source=.\wintouch;Initial Catalog=bbl;User ID=sa;Password=Pa$$w0rd";
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();

            string queryString = "DELETE FROM wgcdoccab WHERE serie ='1' tipodoc ='FSS' AND and contribuinte ='999999990' and  datadoc = CONVERT(varchar(10),(dateadd(dd, -2, getdate())),120) ";                    
            SqlCommand command = new SqlCommand(queryString, connection);
            command.ExecuteNonQuery();
        }
}