VS2012 Linq to SQL retrieving highest ID number

[dolphinsfan1966]

Hi everyone, I'm working with the infamous Northwind database w/in SQL 2008. I'm working on the basic Insert, Update, Delete functions by way of LINQ to SQL. I currently have things working pretty well but I'm having issues with a table that isn't auto-incremented for its ID number.

I'm looking for the equivalent of the C# (I believe) .max method so I can search the table for the highest ID number and increment + 1. The count method isn't working
because if I use that and delete rows and its ID number is the same as the .count, then I will get a unique PK exception thrown.

Any help would be awesome, I've been going at this and search all day to no avail.

This is my Insert Class thus far

Public Class InsertClass    
    Sub insertsub(ByVal regiondescription As String)
        Dim insert As New RegionLinqSQLDataContext
        Dim newregion As New Region With _
        {.RegionDescription = frmInsert.txtboxRegionDesc.Text, _
         .RegionID = insert.Regions.Count + 2}
        insert.Regions.InsertOnSubmit(newregion)
        Try
            insert.SubmitChanges()
            DisplayRegions.Show()
            MessageBox.Show("Insert successful")
        Catch ex As Exception
            MessageBox.Show("Insert not successful")
        End Try
    End Sub
End Class

[jmcilhinney]

Max is not a C# method. It's a .NET method. Just as you use the same Form.Show method to display a form in both C# and VB, so you use the same Enumerable.Max method to get the maximum value from a sequence in both C# and VB. The difference between the two languages is in the syntax of the lambda expression you pass to the Max method. While a C# lambda might look like this:

r => r.RegionID

the equivalent VB lambda would look like this:

Function(r) r.RegionID

[dolphinsfan1966]

So instead of

RegionID = insert.Regions.Count + 2

I'd insert

regionID = max(r) r.RegionID

?

I'm not exactly getting what you're saying.

Thanks for the reply BTW.

[jmcilhinney]

Max is a method that you call on the sequence you want to get the maximum value from and you pass it a lambda expression as an argument. If you've seen it done in C#, which presumably you have if you mention it in relation to C#, then it's called in exactly the same way. As I said, the only different is the syntax of the lambda argument.