ListView SELECT查询不返回任何内容

Question

I am building a library management software and im trying to search books by name. However when I try to use what Ive implemented nothing gets returned.

This is the code behind used to retrieve data from the db.

string constr = ConfigurationManager.ConnectionStrings["LibraryContext"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constr))
        {
            using (SqlCommand cmd = new SqlCommand())
            {
                string bookTitle = Request.QueryString["BookTitle"];
                cmd.Parameters.AddWithValue("@Title", bookTitle); 
                cmd.CommandText = "SELECT * FROM Books WHERE Title LIKE '%@Title%'";
                //cmd.Parameters.AddWithValue("@Title", bookTitle); 
                cmd.Connection = con;

                using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
                {
                    DataTable dt = new DataTable();
                    sda.Fill(dt);
                    lvCustomers.DataSource = dt;
                    lvCustomers.DataBind();
                }
            }
        }

Thank you for you help

Answer 1

Do not put quotes around your parameter

cmd.CommandText = "SELECT * FROM Books WHERE Title LIKE %@Title%";

Quotes aroud the parameters tranform everything inside them to a literal string and of course I suppose that you don't have any book whose title is literally "%@Title%"

also I prefer to use a

cmd.CommandText = "SELECT * FROM Books WHERE Title LIKE @Title";       
cmd.Parameters.Add("@Title", SqlDbType.NVarChar).Value = "%" + bookTitle + "%"); 

AddWithValue is a shortcut with numerous drawback that you need to aware of before trying to use it: Can we stop to use AddWithValue already?