Question

I am creating a booking system, I want to make it so when the user selects a date on the calander the dropdown box will become populated with the times which are available.

Below is the code I have…

Protected Sub Calendar1_SelectionChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles Calendar1.SelectionChanged

    Label1.Text = Calendar1.SelectedDate
    Dim db As New DataClasses2DataContext

    Dim times = From s In db.Apps Where s.Date = Calendar1.SelectedDate Select New With {s.StartTime}

    Dim allslots = From c In db.Slots Select c.StartTime

    Dim leftover = times.Except(allslots)

    DropDownList1.DataSource = leftover
    DropDownList1.DataBind()


End Sub

This is the error I am getting…

Unable to cast object of type ‘System.Data.Linq.DataQuery1[System.TimeSpan]' to type 'System.Collections.Generic.IEnumerable1[VB$AnonymousType_1`1[System.TimeSpan]]’.

From my general knowledge I know that I am going to need a timespan.parse somewhere, I have had a play around with things but cant seem to work it out, can anyone help?

thanks,
Cora.

Answer 1

I think you meant this:

Dim times = From s In db.Apps
            Where s.Date = Calendar1.SelectedDate
            Select s.StartTime

I think you may have gotten the Except backwards. Did you mean this?

Dim leftover = allslots.Except(times)