How to compare textbox value with database value using if..?

Krutika Karekar

8y10.3k

Hello,

I created a login with id and password..i wanna authenticate it database values...so want to use if condition...bt how to compare value from textbox with the value from database in asp.net c#....plz help me

this is my code:

9 Replies

Know the answer? Post it — somebody with the same question will find it here.

Manav Pandya8y ago
Accepted answer
Hello

Before using values of DataReader, you should always check againts null or not

Otherwise it will show exception every time when you access their values

Just try below snippet :
if (myReader["Emp_id"] != DBNull.Value)
{
    // if not null
}
else
{
    // If null
}
Same way you can check every value againts null
Let me know if you need further help

Thanks
0
Krutika Karekar8y ago
Tysm all of you...its working
0
Rafnas T P8y ago
hi,
instead of getting all the records based on userid and password get only count of records and if the count is greater than zero then user is exist else no

change query as below

select count(*) as ttl from LoginTable

instead of select * from LoginTable
and change this
int _count=0;
if(dr.Read())
{
_count=Convert.ToInt16(dr["ttl"].ToString());
}
if(_count>0)
{
Response.Redirect("Home.aspx");
}
else
{
// message
}
0
Chanakya Jayabalan8y ago
You need to ceck for null & if the reader has any rows returned as in belo code.
if(dr!=null)
{
     if (dr.HasRows)
     {
           //your code to access data goes here
     }
}
0
Krutika Karekar8y ago
Hello,
Is it necessary to use datareader ? or can i execute without it...? i am still confused...nt getting anything...plz help me
0
Chanakya Jayabalan8y ago
Hi Krutika,

Looks like your object dr is not getting any results. Check for null values in dr object.
0
Krutika Karekar8y ago
Hello,
sir, i corrected that exception...bt now getting another...plz tell me what is wrong in it...??
and if i do not use datareader, it is not considering the values from table

0
Manav Pandya8y ago
Hello

You have pasted all the code whatever i have given to you, its worng

Keep your code as it is, just use dr["Emp_id"] and dr["Password"]

Than use the code i have provided

Thanks
0
Manav Pandya8y ago
Hello

If you wan to store, value of string than do not use ToString(), instead use like below :
string empId = Convert.toString((dr["Emp_id"]);
string password = Convert.toString((dr["Emp_id"]);
And store texbox data into variable as well :
string myEmpId = Convert.toString(TxtEmp.text);
string myPassword = Convert.toString(TxtPass.text);
Most important is to trim spaces before check :
myEmpId.Trim();
myPassword.Trim();
Now you can compare using if condition as below :
if(empId == myEmpId && password == myPassword)
{
    // do something
}
else
{
    // do something
}
Try to do some R & D and let me know if you need more help
Thanks
0