• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 747
  • Last Modified:

VB.Net - DataTable Row Reference

Good Day Experts!

I have a little project that I am working on - VB6 to VB.Net conversion.  The original VB6 code uses a recordset to loop through the records.  Within the loop, the code checks for EOF. If EOF, then the code backs up one record to get data.  

So, now I am trying to figure out how to make that happen in .Net.  

1) Is there a way at the bottom of my For DataTable loop to check if the current row of  
    the DataTable is the last one?
2) Then, if it is the last row of the DataTable, back up a row in the DataTable so I can
    reference that row data to run a Select query?

Thanks for the help,
jimbo99999
0
Jimbo99999
Asked:
Jimbo99999
  • 5
  • 4
1 Solution
 
Éric MoreauSenior .Net ConsultantCommented:
if you use a "For Each x as DataRow in YourDataTable.Rows"instead of a regular For, you don't need to check for EOF
0
 
Jimbo99999Author Commented:
But I need to check for it so I can do 2).
0
 
Éric MoreauSenior .Net ConsultantCommented:
then you can create your own counter and check if it equals YourDataTable.Rows.Count()
0
Cloud Class® Course: SQL Server Core 2016

This course will introduce you to SQL Server Core 2016, as well as teach you about SSMS, data tools, installation, server configuration, using Management Studio, and writing and executing queries.

 
Jimbo99999Author Commented:
Thanks

This is where I am at so far with referencing the DataTable items based on row Position in the DataTable.  

sqlRStbl.Rows(sqlRStbl_rowPosition)("DIRECTION").Value

Do I need a .Value or .toString  after the Item reference? If so, how do I know which one to use when?

Thanks,
jimbo99999
0
 
Éric MoreauSenior .Net ConsultantCommented:
>>Do I need a .Value or .toString  after the Item reference? If so, how do I know which one to use when?

Very often you don't need because there are some default properties but I personally prefer to always write them.
0
 
Jimbo99999Author Commented:
Ok, thanks.

One more item and I think I will have enough knowledge to give this a shot here.

Normally when I iterate through a DataTable I use the following:

For Each sqlRSProcessing In sqlRStbl.Rows
     Direction = sqlRSProcessing("DIRECTION").Value
Next

In order to be able to reference previous rows in the DataTable,  Is this what I will have to use to loop through the DataTable and reference the values in a row?

Do While sqlRStbl_rowPosition < (sqlRStbl.Row.Count - 1)
     Direction = sqlRStbl.Rows(sqlRStbl_rowPosition)("DIRECTION").Value
Loop

Thanks,
jimbo99999
0
 
Éric MoreauSenior .Net ConsultantCommented:
you want to compare the current value to the previous one?

for i as integer = 0 to sqlRStbl.Row.Count -1
     DirectionCurrent = sqlRStbl.Rows(i)("DIRECTION").Value
     if i > 0 then DirectionPrevious = sqlRStbl.Rows(i-1)("DIRECTION").Value
Loop
0
 
Jimbo99999Author Commented:
Trying to "mimic" the VB6 behavior is harder than I thought...thanks for the patience.

Ok, I just found out that the original VB6 code was moving previous at the EOF to get the last records data...I am not a VB6 coder and did not realize that VB6 EOF puts you past the end of the data.  So, I htink I am good there.

When inside the VB6 Do Until sqlRS.EOF = True loop, several references are made to sqlRS.MoveNext based on code conditions.  To do that I am envisioning having to increment my RowPosition.  So, thinking out loud, then the next time I hit the end of the Loop my Rowposition will then increment again(which is what I want).

Thanks,
jimbo99999
0
 
Jimbo99999Author Commented:
Thanks for the dialogue.  I am all set now.
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Cloud Class® Course: CompTIA Healthcare IT Tech

This course will help prep you to earn the CompTIA Healthcare IT Technician certification showing that you have the knowledge and skills needed to succeed in installing, managing, and troubleshooting IT systems in medical and clinical settings.

  • 5
  • 4
Tackle projects and never again get stuck behind a technical roadblock.
Join Now