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{"Fetch Error:Conversion failed when converting the varchar value 'Data Base' to data type int."}

What I have tried:

private DataTable GetData()
DataTable dt = new DataTable();
SqlConnection connection = new SqlConnection("Data Source=.;Initial Catalog=Quiz_system;Integrated Security=True");
SqlCommand sqlCmd = new SqlCommand("Select question_no,question,op1,op2,op3,op4,correct_ans From tbl_question_bank where course_name='" + lblcorrect.Text.ToString() + "' and quiz_id='"+lblqid.Text+"'", connection);
SqlDataAdapter sqlDa = new SqlDataAdapter(sqlCmd);
catch (System.Data.SqlClient.SqlException ex)
string msg = "Fetch Error:";
msg += ex.Message;
throw new Exception(msg);
return dt;
Updated 13-May-17 16:04pm
[no name] 13-May-17 19:14pm    
How could you possibly have forgotten how to do this correctly since yesterday?
Why are you calling ToString on an object that is already a string? Does that even remotely make any sense to you?
The error message is perfectly clear. What is your actual question here?

1 solution

Never build an SQL query by concatenating with user inputs, it is named "SQL injection", it is dangerous for your database and error prone.
A single quote in a name and your program crash. If a user input like "Brian O'Conner" can crash your app, it is an SQL injection vulnerability.
SQL injection - Wikipedia[^]
SQL Injection[^]
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