As I said in comments - you should always use parameters in your query - NEVER EVER concatenate together your SQL statements yourself.
Also: I would recommend to separate the click event handler from the actual code to insert the data.
So I would rewrite your code to be something like
In your web page's code-behind file (yourpage.aspx.cs)
private void button1_Click(object sender, EventArgs e)
{
string connectionString = "Data Source=DELL-PC;initial catalog=AdventureWorks2008R2 ; User ID=sa;Password=sqlpass;Integrated Security=SSPI;";
InsertData(connectionString,
textBox1.Text.Trim(), -- first name
textBox2.Text.Trim(), -- last name
textBox3.Text.Trim(), -- user name
textBox4.Text.Trim(), -- password
Convert.ToInt32(comboBox1.Text), -- age
comboBox2.Text.Trim(), -- gender
textBox7.Text.Trim() ); -- contact
}
In some other code (e.g. a databaselayer.cs):
private void InsertData(string connectionString, string firstName, string lastname, string username, string password
int Age, string gender, string contact)
{
// define INSERT query with parameters
string query = "INSERT INTO dbo.regist (FirstName, Lastname, Username, Password, Age, Gender,Contact) " +
"VALUES (@FirstName, @Lastname, @Username, @Password, @Age, @Gender, @Contact) ";
// create connection and command
using(SqlConnection cn = new SqlConnection(connectionString))
using(SqlCommand cmd = new SqlCommand(query, cn))
{
// define parameters and their values
cmd.Parameters.Add("@FirstName", SqlDbType.VarChar, 50).Value = firstName;
cmd.Parameters.Add("@Lastname", SqlDbType.VarChar, 50).Value = lastName;
cmd.Parameters.Add("@Username", SqlDbType.VarChar, 50).Value = userName;
cmd.Parameters.Add("@Password", SqlDbType.VarChar, 50).Value = password;
cmd.Parameters.Add("@Age", SqlDbType.Int).Value = age;
cmd.Parameters.Add("@Gender", SqlDbType.VarChar, 50).Value = gender;
cmd.Parameters.Add("@Contact", SqlDbType.VarChar, 50).Value = contact;
// open connection, execute INSERT, close connection
cn.Open();
cmd.ExecuteNonQuery();
cn.Close();
}
}
Code like this:
- is not vulnerable to SQL injection attacks
- performs much better on SQL Server (since the query is parsed once into an execution plan, then cached and reused later on)
- separates the event handler (code-behind file) from your actual database code (putting things where they belong - helping to avoid "overweight" code-behinds with tons of spaghetti code, doing everything from handling UI events to database access - NOT a good design!)
