SqlConnection conn=new SqlConnection (" Persist Security Info=False; User ID=sa; Password=; Initial Catalog=Student; Server=(local) ");
{
conn.Open();
Using (SqlCommand CMD=conn. CreateCommand ())
{
Cmd.Com mandText="select * from T_Users where UserName=@ the UserName";
CMD. The Parameters. The Add (new SqlParameter (" UserName ", this. TxtUsername. Text. The Trim ()));
Using (SqlDataReader reader=CMD. ExecuteReader ())
{

If (reader. The Read ())
{
String dbpassword=reader. Get string (reader. GetOrdinal (" Password "));
If (dbpassword==this. TxtPassword. Text. The Trim ())
{
This. LblResults. Text="login successfully!" ;
}
The else {this. LblResults. Text="login failed"; }
}
The else
{
This. LblResults. Text="user name does not exist";
}
}
}
}

CodePudding user response:

Didn't see this kind of writing, learned the
In general I
are directly using SQL statements

 string ls_name 
String ls_pass 
String ls_temp 

Ls_name=sle_name. Text//input from the user login name 
Ls_pass=sle_pass. Text//user input password 

SELECT the PassWord 
INTO: ls_temp 
The FROM T_Users 
WHERE the UserName=: ls_name AND; 

If the SQLCA. SQLCode=1 then 
MessageBox (" prompt ", "database error, login failed!" + "~ r ~ n" + "error message:" + SQLCA. SQLErrText) 
The else 
If the SQLCA. SQLCode=100 then 
MessageBox (" prompt ", "incorrect login name") 
The else 
If IsNull (ls_temp) then ls_tmep="" 
If IsNull (ls_pass) then ls_pass="" 

If ls_temp & lt;> Ls_pass then 
MessageBox (" prompt ", "wrong password") 
The else 
MessageBox (" prompt ", "login succeeds") 
End the if 
End the if 
End the if 

CodePudding user response:

The original poster should post to the c # version,
Cmd.Com mandText="select * from T_Users where UserName=@ the UserName";
Should be have a problem here, and you change the select * from to select password from a try,