Re: Record Lookup
- From: MikeS <MikeS@xxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Tue, 11 Sep 2007 14:14:03 -0700
Cor....thank you for your vote of confidence. Maybe this sounded more
difficult than it actually is. To put it in simple terms, all I want to do
is seach a table for ONE unique record and read only ONE field from it. I
don't want to edit it....I don't want to modify it.....I don't want to delete
it.....all I want to do is read ONE field from it. And I don't want to
search by the primary key field. I want to be able to search by Employee
Number or First Name or Last Name or any criteria field I choose and return
his or her "Shoe Size".
In VB for Apps I can do this by using a simple statement such as:
MyValue = DLookup("[RequestedField]", "tablename", "[CriteriaField] = " &
textbox)
I just wanted to do the same thing in VB.Net. I apologize for making it so
difficult.
Thanks,
Mike
"Cor Ligthert[MVP]" wrote:
MikeS,.
The problem is that a novice can ask more difficult questions than somebody
who knows what he wants.
You have at least two options:
find what you want in direct in the database
find what you want in a datatable.
For both you got an answer. The first is very well with very hug databases.
The latter is better if it is about smal databases.
Cor
"MikeS" <MikeS@xxxxxxxxxxxxxxxxxxxxxxxxx> schreef in bericht
news:6B01D10B-5A7F-41ED-80E9-8D49B11763C5@xxxxxxxxxxxxxxxx
Patrice, thank you for your comments and effort. Unfortunately, that
doesn't
tell me what I need to know. As I originally mentioned, I am a novice and
any help would have to be in the form of very precise syntax or at least a
very good example. I also mentioned that I tried setting changing the
primary key in the table to the field that I wanted to use for the search
criteria and that didn't work.
Any additional information you could add would be greatly appreciated.
Thanks,
Mike
"Patrice" wrote:
From http://msdn2.microsoft.com/en-us/library/ydd48eyk.aspx (Find
documentation) :
[To use the Find method, the DataTable object to which the
DataRowCollection
object belongs must have at least one column designated as a primary key
column. See the PrimaryKey property for more information about how to
create
a primary key column.]
So Find can only search using the primary key...
Depending on what you are trying to do you could use the DataTable.Select
method or DataTable.DefaultView.RowFilter property to select rows using
a
more general criteria.
A a side note (and I know this is not your code) IMO it would better to
check explicitely if the criteria returns nothing. The code doesn't work
if
a row is not found. It raises an error and then display a message saying
that the row is not found. Actually it will display the message
regardless
of the real reason for which the code fails (for example you could test
if
the found row is nothing so that an error is raised only if you have a
real
error)...
---
Patrice
"MikeS" <MikeS@xxxxxxxxxxxxxxxxxxxxxxxxx> a écrit dans le message de
news:
EF0501C3-CC9B-4A5E-A4F3-DBC53163777E@xxxxxxxxxxxxxxxx
The Access file name is "ItemMaster.dbf"
The table name is "Itemlist"
The field names are "ID (primary), ITNBR, ITDSC, UCDEF"
This is the code that populates the combobox:
cboItemNum.DataSource = ItemMasterDataSet1.Tables("ItemList")
cboItemNum.DisplayMember = "ID"
The following is the code snippet I found to search the table:
Dim strItemNum As String
Dim drSelectedRecord As DataRow
strItemNum = cboItemNum.Text
drSelectedRecord =
ItemMasterDataSet1.ItemList.Rows.Find(strItemNum)
Try
lblItemDesc2.Text = drSelectedRecord(1).ToString & _
" - " & drSelectedRecord(2).ToString
Catch ex As Exception
MsgBox("Record " & strItemNum & " was not found.")
End Try
The problem is I can only search by "ID" and I want to search by
"ITNBR".
I
have
tried changing the primary field and "DisplayMember" to "ITNBR". This
will
change the field in my combo box but I get an error when I do the
lookup.
Let me know if you need any additional information.
Thanks in advance.
Mike
"rowe_newsgroups" wrote:
On Sep 11, 9:18 am, MikeS <Mi...@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
I have searched Google with every possible combination of key words
I
can
imagine and have not been able to find an answer to what I think is
a
very
simple question and probably has a very simple solution.
Keep in mind.....I am a NOVICE programmer, so you will have to spell
it
out
for me.
I am trying to write a very simple program in VB.Net 2005. that will
search
a single Access database table and return the value of one field
based
on
criteria that I provide for any other field I choose. The only way
I
have
had any success is if I search by the primary key field, which does
not
give
me the versatility that I need.
Can anyone point me to some sample code that will help me accomplish
this?
Thanks in advance.
Mike
You should connect with the OleDb database providers and then do the
search with a simple Sql query.
If you post a bit of the target table's schema (column names mainly)
and tell me which fields you need to search I'll be more than happy to
write up some simple code for you.
Thanks,
Seth Rowe
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