tolong koreksi coding ane para mastah. pas ane klik muncul pesan error "command parameter 1 is invalid"

Dim username, password, temp1, temp2 As String

 Dim Read As OleDb.OleDbDataReader

 If ComboBox1.Text <> "" And TextBox1.Text <> "" Then

 username = UCase(ComboBox1.Text)

 password = UCase(TextBox1.Text)

 temp = UCase(TextBox1.Text)



 [B] OleDbCommand2.Parameters.AddWithValue("@USER_NAME", OleDbType.LongVarChar)[/B]

 OleDbCommand2.Parameters("USER_NAME").Value = username

 OleDbConnection1.Open()

 Read = OleDbCommand2.ExecuteReader()



 With Read

 While .Read

 temp1 = .GetValue(0)

 temp2 = .GetValue(1)

 End While

 End With

 OleDbConnection1.Close()

thx para mastah sebelum nya, ane cuma bs kasih
ane tunggu comment nya mastah