c# - Asp.Net SQL 更新语句

Question

我的页面上有一个 Asp.net 应用程序，用户请求删除用户。然后这会填充我的“Admin_TaskList”数据库。

然后管理员进入站点的安全区域并输入用户名并单击按钮。确认后，用户将从我的“用户”数据库中删除(已经开始工作)，但我希望我的“Admin_TaskList”数据库“状态”列从“待办事项”更改为“已完成”。

令我难过的是，删除位正在工作，但我正在努力更新我的其他表。

我试过的代码片段

conn.Open();
SqlCommand cmd2 = new SqlCommand("UPDATE FROM Admin_TaskList SET Status = 'Complete' WHERE Description = 'Remove User' AND Name = @Name", conn);
cmd2.Parameters.AddWithValue("@Name", txtRemoveUser.Text);
SqlDataReader rd2 = cmd2.ExecuteReader();
conn.Close();

完整代码

public void btnRemoveConfirmYes_Click(object sender, EventArgs e)
        {
            string connection = ConfigurationManager.ConnectionStrings["PaydayLunchConnectionString1"].ConnectionString;
            SqlConnection conn = new SqlConnection(connection);

            conn.Open();
            SqlCommand cmd1 = new SqlCommand("DELETE FROM Users WHERE Name = @Name", conn);
            cmd1.Parameters.AddWithValue("@Name", txtRemoveUser.Text);
            SqlDataReader rd1 = cmd1.ExecuteReader();
            conn.Close();

            conn.Open();
            SqlCommand cmd2 = new SqlCommand("UPDATE FROM Admin_TaskList SET Status = 'Complete' WHERE Description = 'Remove User' AND Name = @Name", conn);
            cmd2.Parameters.AddWithValue("@Name", txtRemoveUser.Text);
            SqlDataReader rd2 = cmd2.ExecuteReader();
            conn.Close();

            txtRemoveUser.Text = "";
            Response.Redirect("/AdminSide/TaskList.aspx");
        }

Answer 1

不使用 SqlDataReader 来更新值，而是使用 SqlCommand.ExecuteNonQuery :

int updated = cmd2.ExecuteNonQuery();

请记住，您需要对修改数据的命令使用 ExecuteNonQuery，例如 Delete、Insert 或 Update .

MSDN:

You can use the ExecuteNonQuery to perform catalog operations (for example, querying the structure of a database or creating database objects such as tables), or to change the data in a database without using a DataSet by executing UPDATE, INSERT, or DELETE statements.

完整方法:

int deleted, updated;
string connection = ConfigurationManager.ConnectionStrings["PaydayLunchConnectionString1"].ConnectionString;

using (var conn = new SqlConnection(connection))
{
    conn.Open();
    string delSql = "DELETE FROM Users WHERE Name = @Name";
    using (var cmd = new SqlCommand(delSql, conn))
    {
        cmd.Parameters.Add("@Name", SqlDbType.NVarChar).Value = txtRemoveUser.Text;
        deleted = cmd.ExecuteNonQuery();
    }

    string updSql = @"UPDATE Admin_TaskList 
                      SET Status = 'Complete' 
                      WHERE Description = 'Remove User' 
                      AND Name = @Name";
    using (var cmd = new SqlCommand(updSql, conn))
    {
        cmd.Parameters.Add("@Name", SqlDbType.NVarChar).Value = txtRemoveUser.Text;
        updated = cmd.ExecuteNonQuery();
    }
}