Question

我的页面中有此代码

 public partial class Reports : System.Web.UI.Page
    {

       private string myquery = null;
        MySqlConnection conn = new MySqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);


        protected void Page_Load(object sender, EventArgs e)
        {

           usertype = Session["usertype"].ToString();
            {


                if (usertype == "admin")
                {
                    string myquery = @"SELECT jobId, odometerReading, jobDescription, status  FROM joborder Where truck_id = '" + truck_id + "'";
                }
                else
                {
                    string myquery = @"SELECT jobId, odometerReading, jobDescription, status  FROM joborder Where truck_id = '" + truck_id + "' and status = '1'";
                }

            }
            connectDB();
        }
}

如何在我的pageload类中将myquery字符串值设置为if else语句？我当前的代码始终将myquery设置为null。

Answer 1

在你的if / else语句中，你是第二次声明myquery。如果你删除了string关键字，你应该是金色的;

  if (usertype == "admin")
        {
            myquery = @"SELECT jobId, odometerReading, jobDescription, status FROM joborder Where truck_id = '" + truck_id + "'";
        }
        else
        {
            myquery = @"SELECT jobId, odometerReading, jobDescription, status  FROM joborder Where truck_id = '" + truck_id + "' and status = '1'";
        }

目前，您在if / else语句中创建的新变量由于它们在创建后超出范围而丢失，因此您也无法访问它们。

Answer 2

public partial class Reports : System.Web.UI.Page
{

   private string myquery = string.Emplty; //Try use this
    MySqlConnection conn = new MySqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);


    protected void Page_Load(object sender, EventArgs e)
    {

       usertype = Session["usertype"].ToString();

            if (usertype == "admin")
            {
                myquery = @"SELECT jobId, odometerReading, jobDescription, status  FROM joborder Where truck_id = '" + truck_id + "'";
            }
            else
            {
                myquery = @"SELECT jobId, odometerReading, jobDescription, status  FROM joborder Where truck_id = '" + truck_id + "' and status = '1'";
            }

        connectDB();
     }
}

Answer 3

使用sql数据读取器从sql server读取数据

 SqlCommand command ;
 if (usertype == "admin")
    {
          command = new SqlCommand("SELECT jobId, odometerReading, jobDescription, status FROM joborder Where truck_id = '" + truck_id + "'",connection);
connection.Open();

        }
        else
        {
  command = new SqlCommand("SELECT jobId, odometerReading, jobDescription, status  FROM joborder Where truck_id = '" + truck_id + "' and status = '1'",connection);
    connection.Open();
        }
      SqlDataReader reader = command.ExecuteReader();

C＃ASP.NET将if语句字符串值传递给另一个字符串

3 个答案: