Determine if duplicates exist

[jcs1953]

This is the code I'm using:

Dim mytable1 As DataTable
mytable1 = DAL.GetCombinedPSAResults(TBPID.Text)
Dim dr As New DataTableReader(mytable1)
mytable1.Load(dr)
Dim dv As DataView = mytable1.DefaultView
Dim mytable2 As DataTable
mytable2 = DAL.GetOraclePSAResults(TBPID.Text)
Dim dr2 As New DataTableReader(mytable2)
mytable1.Load(dr2)
Dim dv1 As DataView = mytable1.DefaultView
recordcount = dv1.Count

This will return a datatable with the results of the 2 functions combined. The table has 2 columns, Date and Results. I use the data to create a chart. Unfortunately now I have run into a situation where several of the Date values are the same and that doesn't work well in a chart. So what I need is a way to determine if there are duplicate values in the Date column so i can display the data in a gridview instead of a chart.

If (date column has duplicates) Then
put data in gridview
Else
Use data for chart

Thanks for your help.

 

[jmeckley]

1. sort table by date.
2. loop through table comparing current record to previous record.

if at any point the previous = current load into grid, else load into chart.

Jason Meckley
Programmer
Specialty Bakers, Inc.

faq855-7190

 

[jcs1953]

So sorting would be
dv1.sort = "Date DESC"

I'm getting confused on the looping part. Would I set a variable first to the date value?

 

[jmeckley]

if(table.Rows.Count == 0)
{
   load chart;
}
else
{
   var useChart = true;

   var view = table.DefaultView;
   view.Sort = "date field asc. or desc.";
   var previous = view[0];

   for(var i = 1; i < table.Rows.Count; i++)
   {
        var current = view[i];
        if(current["date"] == previous["date"])
        {
            useChart = false;
            break;
        }
        previous = current;
   }

   if(useChart)
   {
      load chart;
   }
   else
   {
      load grid;
   }
}

Jason Meckley
Programmer
Specialty Bakers, Inc.

faq855-7190

 

[jcs1953]

Hi Jason,
Thanks for the example. I'm trying to follow it but am C# illiterate (and it seems VB illiterate sometimes too). Could you please translate to VB?
Thanks

 

[jmeckley]

there are online translators. and it's basics syntax, if/else, indexing, declarations.

Jason Meckley
Programmer
Specialty Bakers, Inc.

faq855-7190

 

[jcs1953]

Thanks again Jason. I had no idea there were online C# to VB converters! It's those little things ......

 

[taree]

If you google you probably find a bunch of them. this the one I use often and It does a good job of converting c# to vb.net

http://www.developerfusion.com/tools/convert/csharp-to-vb/

 

[jcs1953]

I converted the code to VB but there are 2 parts that I don't understand.



1. If table.Rows.Count = 0 Then
2. Dim chart As load
3. Else
4. Dim useChart = True
5.
6. Dim view = table.DefaultView
7. view.Sort = "date field asc. or desc."
8. Dim previous = view(0)
9.
10. For i = 1 To table.Rows.Count - 1
11. Dim current = view(i)
12. If current("date") = previous("date") Then
13. useChart = False
14. Exit For
15. End If
16. previous = current
17. Next
18.
19. If useChart Then
20. Dim chart As load
21. Else
22. Dim grid As load
23. End If
24. End If

If table.Rows.Count = 0 Then Dim chart As load

Why load a chart if the table has no rows and what is "load"? Is that a property in C# that's not in VB?

 

[jmeckley]

it's pseudo code. if there are no rows do "X" else load a chart or a grid, your choice.

Jason Meckley
Programmer
Specialty Bakers, Inc.

faq855-7190

 

[jcs1953]

OK. Thanks.

 

[jcs1953]

Got it work. Thanks Jason. I just wish there were some type of converter to translate VB into plain English!