Check if value exist in DBF database - vb.net

Question

I am trying to check if value "IAV-1419" exist in second column (ColName) in database named PROMGL.DBF.
I get this error : No value give for one or more required parameters
Dim con As New OleDbConnection
Dim cmd As New OleDbCommand
Dim FilePath As String = "C:\"
Dim DBF_File As String = "PROMGL"
Dim ColName As String = "[NALOG,C,8]"
con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & FilePath & _
" ;Extended Properties=dBASE IV"
cmd = New OleDbCommand("SELECT * FROM PROMGL WHERE [NALOG,C,8] = #NAL")
cmd.Connection = con
con.Open()
cmd.Parameters.AddWithValue("#NAL", "IAV-1419")
Using reader As OleDbDataReader = cmd.ExecuteReader()
If reader.HasRows Then
con.Close()
Label6.Text = "EXIST"
TextBox1.Text = ""
TextBox1.Focus()
Else
Label6.Text = "DOESN'T EXIST"
End If
End Using
I am stuck here, if anyone could please check this code for me.

Answer 1

are you sure that your connectionstring is correct????
Data Source=" & FilePath &
how connection string know the database where it point only to "C:\" i think is missing database name
Another personal suggestion make your code more simple to read in example :
Dim FilePath As String = "C:\"
Dim DBF_File As String = "PROMGL"
Dim ColName As String = "[NALOG,C,8]"
Using con As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & FilePath & _
" ;Extended Properties=dBASE IV")
con.Open()
Using cmd As New OleDbCommand("SELECT * FROM PROMGL WHERE [NALOG,C,8] = #NAL", con
cmd.Parameters.AddWithValue("#NAL", "IAV-1419")
Using reader As OleDbDataReader = cmd.ExecuteReader()
If reader.HasRows Then
Label6.Text = "EXIST"
TextBox1.Text = ""
TextBox1.Focus()
Else
Label6.Text = "DOESN'T EXIST"
End If
End Using
End Using
End Using