VB.net ComboBox Event SelectedIndexChanged เกิด Error There is no row at position 0

Private Sub frmCustomer_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        
        Dim CustID As Integer = 0
        Dim CustName As String = ""
        Dim dt As DataTable = Nothing

        dt = _QueryAsDataTable($"SELECT CustID,custName FROM tblCustomer WHERE custName = '{cboName.Text}'") 'เป็นเมทตอท เอา sql เป็น datatable
        CustID = dt.Rows(0).Item(0)
        CustName = dt.Rows(0).Item(1)        
    End Sub

 Private Sub cboName_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cboName.SelectedIndexChanged
       Dim CustID As Integer = 0
        Dim CustName As String = ""
        Dim dt As DataTable = Nothing

        dt = _QueryAsDataTable($"SELECT CustID,custName FROM tblCustomer WHERE custName = '{cboName.Text}'") 'เป็นเมทตอท เอา sql เป็น datatable
        CustID = dt.Rows(0).Item(0)
        CustName = dt.Rows(0).Item(1)        
    End Sub