[tendaimare]

I am using the code I have shown below to loop through my datatable in search of certain values and when i find those values I remove them from the datatable. I am using the below to do this:

 If myTable.Rows.Count = 0 Then

            Else
                'Try
                For Each myDataRow As DataRow In dTable.Rows
                    For myArraySearch As Integer = 0 To 50 Step 1
                        dTable.Rows.RemoveAt(dTable.Rows.IndexOf(dTable.Rows.Find(myArray(myArraySearch))))
                    Next
                Next
                'Catch ex As Exception
                'End Try
            End If

When I remove the try catch statement I get the error "There is no row at position -1.". Is there a way to contain this error without having to use the try catch statement.

[Atli]

Yes. Your mistake there is to assume that the IndexOf() call will return a valid index. If the myArray(myArraySearch) object can not be found among the rows of the dTable, then the Find() call will return a null, which in turn means that IndexOf(Find()) returns -1. That's what's causing the exception, because RemoveAt() call is expecting a valid, positive integer, but it's getting -1.

You can easily test for that using a simple IF statement. Check the value of the IndexOf() call, and make sure it's not -1 before you call RemoveAt()

[AdamSpeight2008]

Still not going to work, even if you did that. As you'll change the enumerator on .Rows

[Atli]

Good point. Assuming there are actually 50 myArray elements, removing the outer loop altogether should fix that though.

[tendaimare]

thanks Atli and AdamSpeight2008. I resorted to using this code instead

  For Each key In myArray
                    Dim row = dTable.Rows.Find(key)

                    If row IsNot Nothing Then
                        dTable.Rows.Remove(row)
                        'row.Delete()
                    End If
                Next

[AdamSpeight2008]

I was slightly incorrect about it modifying the collection, it won't change until you do. I'd forgot it involved a two part process;-

• Generates a list of change want to happen to data
  
• Accept (& apply) those changes.

dTable.AccectChanges()

so using a LINQ query to get the rows, which you want to remove.

Dim re = From r in dTable.Rows
         Where myArray.Contains(r)
Foreach e in re
 e.Delete()
Next
dTable.AcceptChanges()

This post has been edited by AdamSpeight2008: 27 July 2012 - 04:57 PM