?
Solved

How Do I execute a DLookUp function in VB.Net

Posted on 2014-04-07
3
Medium Priority
?
2,754 Views
Last Modified: 2014-05-04
I have been using the following code in access for a number of years, now that i have moved to VB.net i need the equivalent, is there such a function?

If IsNull(DLookup("[txtname]", "Advisories", "[txtname]='" & Me![ReportedBy] & "'")) Then
Exit Sub
End If

Open in new window

0
Comment
Question by:mickeyshelley1
  • 2
3 Comments
 
LVL 22

Expert Comment

by:plusone3055
ID: 39984162
the equvlilant of Dlookup in VB.NET is to use a SQL Query
0
 
LVL 22

Expert Comment

by:plusone3055
ID: 39984184
an example would be


 Dim con As New SqlConnection
        Dim cmd As New SqlCommand
        Errorbox.Text = ""

        Try
            con.ConnectionString = "Data Source=XXXXX;Initial Catalog=EAFiles;Persist Security Info=True;User ID=Login;Password=XXXXXXX"
            con.Open()
            cmd.Connection = con
            cmd.CommandText  "SELECT name, advisoroes WHERE Name = txtname"
cmd.ExecuteNonQuery()

if isnull then
exit sub
end if

Catch ex As Exception
                        Errorbox.Text = "Error while inserting record on table..." & ex.Message
        Finally
            con.Close()
        End Try  

endsub
0
 
LVL 83

Accepted Solution

by:
CodeCruiser earned 2000 total points
ID: 39985618
A better, working example would be

Public Function DLookup(TableName As String, FieldName As String, FieldValue As String) As Object
Dim con As New SqlConnection
Dim cmd As New SqlCommand
Dim retVal As Object = Nothing

Try
     con.ConnectionString = "Data Source=XXXXX;Initial Catalog=EAFiles;Persist Security Info=True;User ID=Login;Password=XXXXXXX"
     con.Open()
     cmd.Connection = con
     cmd.CommandText  "SELECT Count(*) FROM " & TableName & " WHERE " & FieldName & " = '" & FieldValue & "'"
     retVal = cmd.ExecuteScalar()
Catch ex As Exception
  Msgbox "ERROR: " & VBCRLF & ex.Tostring
Finally
  cmd.Dispose()
  con.Close()
End Try  
Return retVal
End Function

Open in new window



Note: This method is not complete as it does not perform any validation on the input which may leave it open to SQL Injection attacks and it only deals with string (varchar) fields currently and so is only intended as an example
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

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

The ECB site provides FX rates for major currencies since its inception in 1999 in the form of an XML feed. The files have the following format (reducted for brevity) (CODE) There are three files available HERE (http://www.ecb.europa.eu/stats/exch…
Calculating holidays and working days is a function that is often needed yet it is not one found within the Framework. This article presents one approach to building a working-day calculator for use in .NET.
Watch the video to learn how one can deal with PST file corruption issue with an outstanding Kernel for Outlook PST Repair Tool easily. Using this tool, non-technical users can swiftly perform the repair process to restore their essential data witho…
Watch the working video to know how to import Outlook PST/OST files to Amazon WorkMail. Kernel released this tool which is very easy to use and migrate single or multiple PST and OST files to Amazon WorkMail. To know more about Kernel Import PST to …

589 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question