我想基于会话ID在ASP.NET文本框上显示数据。但页面上没有任何反应。

问题描述

SqlConnection con = new SqlConnection（Data Source = USER-PC; Initial Catalog = 1GCAttendanceManagementSystem; Integrated Security = True）;

DataTable dt = new DataTable（）;

con.Open（）;

SqlDataReader myReader = null;

SqlCommand myCommand = new SqlCommand（select * from Employee where EmpUsername ='+ Session [ id] +'，con）;



myReader = myCommand.ExecuteReader（）;



while（myReader.Read（））

{

txtCode.Text =（myReader [EmployeeId]。ToString（））;

txtUsername.Text =（myReader [EmpUsername]。ToString（））;

txtPass.Text =（myReader [EmpPassword]。ToString（））;

txtEmail.Text =（myReader [EmpEmail]。ToString（））;

txtFirstname.Text =（myReader [EmpFirstName]。ToString（））;

txtLastname.Text =（myReader [EmpLastName ] .ToString（））;

txtGender.Text =（myReader [EmpGender]。ToString（））;

txtContact.Text =（myReader [EmpContact] ] .ToString（））;

txtAddress.Text =（myReader [EmpAddress]。ToString（））;

txtDept.Text =（myReader [EmpDept] ] .ToString（））;



}

con.Close（）;



我尝试了什么：



我尝试过编码。但是所有文本框都是空白的。什么都没发生。

SqlConnection con = new SqlConnection("Data Source=USER-PC;Initial Catalog=1GCAttendanceManagementSystem;Integrated Security=True");
DataTable dt = new DataTable();
con.Open();
SqlDataReader myReader = null;
SqlCommand myCommand = new SqlCommand("select * from Employee where EmpUsername='" + Session["id"] + "'", con);

myReader = myCommand.ExecuteReader();

while (myReader.Read())
{
txtCode.Text = (myReader["EmployeeId"].ToString());
txtUsername.Text = (myReader["EmpUsername"].ToString());
txtPass.Text = (myReader["EmpPassword"].ToString());
txtEmail.Text = (myReader["EmpEmail"].ToString());
txtFirstname.Text = (myReader["EmpFirstName"].ToString());
txtLastname.Text = (myReader["EmpLastName"].ToString());
txtGender.Text = (myReader["EmpGender"].ToString());
txtContact.Text = (myReader["EmpContact"].ToString());
txtAddress.Text = (myReader["EmpAddress"].ToString());
txtDept.Text = (myReader["EmpDept"].ToString());

}
con.Close();

What I have tried:

I have tried the coding. But all the textbox are blank. Nothing happen at all.

推荐答案

if (string.IsNullOrEmpty(Session["id"])) { throw new Exception("Session ID has not been set");}

2）运行调试器下的代码，并在 catch 阻止。



3）你的代码通常不是很好。这样做是这样的：

2) Run the code under the debugger with a breakpoint set in the catch block.

3) Your code is generally not really built well. Do it this way instead:

try
{
    if (string.IsNullOrEmpty(Session["id"])) 
    {
        // throw an exception so that the code doesn't perform an unnecessary 
        // database query
        throw new Exception("Session ID has not been set");
    }
    using (SqlConnection con = new SqlConnection("Data Source=USER-PC;Initial Catalog=1GCAttendanceManagementSystem;Integrated Security=True"))
    {
        DataTable dt = new DataTable();
        con.Open();
        SqlDataReader myReader = null;
        using (SqlCommand myCommand = new SqlCommand("select * from Employee where EmpUsername='" + Session["id"] + "'", con){CommandType=CommandType.Text})
        {
            myReader = myCommand.ExecuteReader();
            if (!myReader.HasRows)
            {
                // Do something if the reader doesn't have data. This could be an exception 
                // or other indication to the user that something unexpected happened.
            }
            while (myReader.Read())
            {
                // The exception handler will trigger if the expected fields don't exist 
                // in the returned row
                txtCode.Text = (myReader["EmployeeId"].ToString());
                txtUsername.Text = (myReader["EmpUsername"].ToString());
                txtPass.Text = (myReader["EmpPassword"].ToString());
                txtEmail.Text = (myReader["EmpEmail"].ToString());
                txtFirstname.Text = (myReader["EmpFirstName"].ToString());
                txtLastname.Text = (myReader["EmpLastName"].ToString());
                txtGender.Text = (myReader["EmpGender"].ToString());
                txtContact.Text = (myReader["EmpContact"].ToString());
                txtAddress.Text = (myReader["EmpAddress"].ToString());
                txtDept.Text = (myReader["EmpDept"].ToString());
            }
        }
    }
    // Put a breakpoint on the following curly brace so you can establish that the 
    // code is working without problems (assuming your ducks are otherwise all in a row)
}
catch (Exception ex)
{
    // do something appropriate to indicate whatever problem arises
    // if you're debugging, put a breakpoint on either of the curly braces to stup exceution
}

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