c# - 在sql数据库表中插入新行

Question

我的应用程序中有文本框。在这些文本框中输入的数据将被插入到数据库中。 commandString 只接受字符串类型。那么，如何实现插入语句呢？

string cmdString="INSERT INTO books (name,author,price) VALUES (//what to put in here?)"

我是否需要为每个值将 cmdString 与 textBox.Text 连接起来，还是有更好的选择？

Answer 1

使用命令和参数来防止SQL注入(inject)

// other codes
string cmdString="INSERT INTO books (name,author,price) VALUES (@val1, @va2, @val3)";
using (SqlCommand comm = new SqlCommand())
{
    comm.CommandString = cmdString;
    comm.Parameters.AddWithValue("@val1", txtbox1.Text);
    comm.Parameters.AddWithValue("@val2", txtbox2.Text);
    comm.Parameters.AddWithValue("@val3", txtbox3.Text);
    // other codes.
}

• AddWithValue
• Add (recommended method to use)

完整代码:

string cmdString="INSERT INTO books (name,author,price) VALUES (@val1, @va2, @val3)";
string connString = "your connection string";
using (SqlConnection conn = new SqlConnection(connString))
{
    using (SqlCommand comm = new SqlCommand())
    {
        comm.Connection = conn;
        comm.CommandString = cmdString;
        comm.Parameters.AddWithValue("@val1", txtbox1.Text);
        comm.Parameters.AddWithValue("@val2", txtbox2.Text);
        comm.Parameters.AddWithValue("@val3", txtbox3.Text);
        try
        {
            conn.Open();
            comm.ExecuteNonQuery();
        }
        Catch(SqlException e)
        {
            // do something with the exception
            // don't hide it
        }
    }
}