How to write an efficient, secure SQL query code---(very basic, but it is easy to ignore)

Security take a look at this code, let's look at the main problems

Set up SQL statements
insertstr= INSERT INTO UserInfo (name,password,email,phone,mobile,post,address) VALUES (' ";
Insertstr + = This._name. Trim () + "', '";
Insertstr + = This._password. Trim () + "', '";
Insertstr + = This._email. Trim () + "', '";
Insertstr + = This._phone. Trim () + "', '";
Insertstr + = This._mobile. Trim () + "', '";
Insertstr + = This._post. Trim () + "', '";
Insertstr + = this._address. Trim () + "')";


1. Efficiency issues
First look at the above code, the efficiency is too low, so many strings connected to their own efficiency is low enough, plus all these trim (), there is no need.

2, the correctness of the problem
This code is so fragile that a single quote can crash the entire program.

3. Safety
Ditto, using single quotes I can do a lot of things, such as running a xp_cmd command, then you are miserable, hehe.

So, how to write, the above code can be changed to this:
String strSQL = "INSERT into sometable (c1, C2, C3, ...) VALUES (@c1, @c2, @c3,...) "
SqlCommand mycommand = new SqlCommand (strSQL, myconn)
Try
{
MYCOMMAND.PARAMETERS.ADD (New SqlParameters ("@c1", Sqldatatype.varchar, 20)
mycommand.parameters["@c1"]. Value = This._name;
....
There are several plus several
....
}
catch (...)
...

In this way, the inefficient string connection can be avoided, and the SqlCommand parameter validity detection can be used to avoid the appearance of illegal characters, and because this parameter method is precompiled and more efficient.

Count it, why not.