How to Properly Use Prepared Statements with MySQL in C#?

Using Prepared Statements in C# with MySQL

When attempting to implement prepared statements in a C# program, some users may encounter issues if they have not properly formatted their query or prepared the statement after adding parameters.

To resolve these issues, follow these steps:

1. Remove single quotes from the query: In the provided code, the query is enclosed in single quotes. This is not necessary and should be removed.
2. Use Prepare after adding parameters: Before executing the query, the statement must be prepared. This process creates a plan for executing the query efficiently. Place the Prepare() method call after adding all necessary parameters using cmd.Parameters.AddWithValue().

The corrected code should look like this:

private void btnLogin_Click(object sender, EventArgs e)
{
    MySqlCommand cmd = MySqlConn.cmd;
    cmd = new MySqlCommand("SELECT * FROM admin WHERE admin_username=@val1 AND admin_password=PASSWORD(@val2)", MySqlConn.conn);
    cmd.Parameters.AddWithValue("@val1", tboxUserName.Text);
    cmd.Parameters.AddWithValue("@val2", tboxPassword.Text);
    cmd.Prepare();

    MySqlDataReader res = cmd.ExecuteReader();
    if (!res.HasRows) { MessageBox.Show("Error! "); res.Close(); return; }
    else
    {
        //do something
    }
    res.Close();
}

The above is the detailed content of How to Properly Use Prepared Statements with MySQL in C#?. For more information, please follow other related articles on the PHP Chinese website!