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aspx thread: Null value trapping on forms driving me mad!
Message #1 by "Charles Emerson" <charles@S...> on Tue, 29 Jan 2002 15:07:19
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I am trying to make a simple edit form and populate it unbound from a SQL
database and am having fits with how to trap null values to keep it from
blowing up my asp.net form.
' Obtain a single row of document information
Dim Timekeepers As New Billing.TimekeepersDB()
Dim dr As SqlDataReader = Timekeepers.GetSingleTimekeeper(TimekeeperId)
' Load first row into Datareader dr.Read()
txtFirstName.Text = CStr(dr("FirstName"))
This work fine if there's a valid value, but crashes with evil if the
value is null - how best to code this - it's so easy in Access & VB, but
I'm ready to jump!
Also, type conversions are most unforgiving - such as money fields or
boolean checkboxes.
I love the granularity of asp.net, but there's alot of coding to get
stuff done, and any error blows up the app.
Thanks all.
Charles Emerson
Message #2 by "Alvin Ling" <alvin.ling@i...> on Tue, 29 Jan 2002 10:25:51 -0500
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Not sure if it's the answer you're looking for but you could process
null values on the DB
SELECT ISNULL(firstname, 'Unknown')
FROM ...
Or if applicable, exclude null values from your query altogether with a
where clause.
Alvin
> -----Original Message-----
> From: Charles Emerson [mailto:charles@S...]
> Sent: Tuesday, January 29, 2002 3:07 PM
> To: ASP+
> Subject: [aspx] Null value trapping on forms driving me mad!
>
>
> I am trying to make a simple edit form and populate it
> unbound from a SQL
> database and am having fits with how to trap null values to
> keep it from
> blowing up my asp.net form.
>
> ' Obtain a single row of document information
>
> Dim Timekeepers As New Billing.TimekeepersDB()
> Dim dr As SqlDataReader =
> Timekeepers.GetSingleTimekeeper(TimekeeperId)
>
> ' Load first row into Datareader dr.Read()
>
> txtFirstName.Text = CStr(dr("FirstName"))
>
> This work fine if there's a valid value, but crashes with evil if the
> value is null - how best to code this - it's so easy in
> Access & VB, but
> I'm ready to jump!
>
> Also, type conversions are most unforgiving - such as money fields or
> boolean checkboxes.
>
> I love the granularity of asp.net, but there's alot of coding to get
> stuff done, and any error blows up the app.
>
> Thanks all.
>
> Charles Emerson
>
>
>
>
>
>
>
Message #3 by "Samuel Engelman" <samuel_engelman@p...> on Tue, 29 Jan 2002 10:40:31 -0500
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Why don't you try the true and tested txtFirstName.Text = CStr(dr("FirstName" +
""))?
|--------+--------------------------------->
| | "Charles Emerson" |
| | <charles@S...> |
| | |
| | |
| | Tuesday January 29, 2002 10:07|
| | AM |
| | Please respond to "ASP+" |
| | |
|--------+--------------------------------->
>------------------------------------------------------------|
| |
| To: "ASP+" |
| <aspx@p...> |
| cc: |
| Subject: [aspx] Null value trapping on forms driving |
| me mad! |
>------------------------------------------------------------|
I am trying to make a simple edit form and populate it unbound from a SQL
database and am having fits with how to trap null values to keep it from
blowing up my asp.net form.
' Obtain a single row of document information
Dim Timekeepers As New Billing.TimekeepersDB()
Dim dr As SqlDataReader = Timekeepers.GetSingleTimekeeper(TimekeeperId)
' Load first row into Datareader dr.Read()
txtFirstName.Text = CStr(dr("FirstName"))
This work fine if there's a valid value, but crashes with evil if the
value is null - how best to code this - it's so easy in Access & VB, but
I'm ready to jump!
Also, type conversions are most unforgiving - such as money fields or
boolean checkboxes.
I love the granularity of asp.net, but there's alot of coding to get
stuff done, and any error blows up the app.
Thanks all.
Charles Emerson
Message #4 by ToddC@m... on Tue, 29 Jan 2002 10:48:01 -0600
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Or just stop creating fields that allow nulls. Just default them to empty
string or 0. Nulls require special handling for DB server and the
Programmer, and the end user doesn't give a damn.
Tc
Keep it lean and fast.
-----Original Message-----
From: Alvin Ling [mailto:alvin.ling@i...]
Sent: Tuesday, January 29, 2002 9:26 AM
To: ASP+
Subject: [aspx] RE: Null value trapping on forms driving me mad!
Not sure if it's the answer you're looking for but you could process
null values on the DB
SELECT ISNULL(firstname, 'Unknown')
FROM ...
Or if applicable, exclude null values from your query altogether with a
where clause.
Alvin
> -----Original Message-----
> From: Charles Emerson [mailto:charles@S...]
> Sent: Tuesday, January 29, 2002 3:07 PM
> To: ASP+
> Subject: [aspx] Null value trapping on forms driving me mad!
>
>
> I am trying to make a simple edit form and populate it
> unbound from a SQL
> database and am having fits with how to trap null values to
> keep it from
> blowing up my asp.net form.
>
> ' Obtain a single row of document information
>
> Dim Timekeepers As New Billing.TimekeepersDB()
> Dim dr As SqlDataReader =
> Timekeepers.GetSingleTimekeeper(TimekeeperId)
>
> ' Load first row into Datareader dr.Read()
>
> txtFirstName.Text = CStr(dr("FirstName"))
>
> This work fine if there's a valid value, but crashes with evil if the
> value is null - how best to code this - it's so easy in
> Access & VB, but
> I'm ready to jump!
>
> Also, type conversions are most unforgiving - such as money fields or
> boolean checkboxes.
>
> I love the granularity of asp.net, but there's alot of coding to get
> stuff done, and any error blows up the app.
>
> Thanks all.
>
> Charles Emerson
>
>
>
>
>
>
>
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