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

Question

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:

Manav Pandya · 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

Chanakya Jayabalan · Answer

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 } }

Krutika Karekar · Answer

Tysm all of you...its working

Rafnas T P · Answer

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 }

Krutika Karekar · Answer

Hello, Is it necessary to use datareader ? or can i execute without it...? i am still confused...nt getting anything...plz help me

Chanakya Jayabalan · Answer

Hi Krutika, Looks like your object dr is not getting any results. Check for null values in dr object.

Krutika Karekar · Answer

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

Manav Pandya · Answer

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

Manav Pandya · Answer

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