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aspx thread: Testing textbox for null
Message #1 by "Hugh McLaughlin" <hugh@k...> on Fri, 21 Jun 2002 23:30:45
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Hello Everyone and thanks for your help in advance. I am working on an
application that builds a SQL query based on whether data has been
entered into a text field. An example is located at:
http://www.famb.org/roster.aspx
Basically, the idea is to check and see if there is data entered into the
first or last anme fields and build the query accordingly. The code is:
Dim SQL As String = "Select * From tblMembers"
If Trim(LastName.Text)<>"" OR Not(IsDBNull(Trim(LastName.Text))) Then
SQL=SQL & " WHERE LastName LIKE '" & LastName.Text & "%'"
End If
However, whether I enter data into the last name field or not, the WHERE
clause that should be inserted only if data is present, continues to be
inserted. Obviously, my "If...Then" is not working properly, but I don't
understand why. Any help would be greatly appreciated. Thanks.
Message #2 by "James Scot Johnston" <scotj@i...> on Fri, 21 Jun 2002 15:26:17 -0700
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I believe from a quick look you want to use the [AND} operator not [OR]
because you want to fail if both condition of "" or null are met =3D)
J. Scot
IronSpire Inc.
-----Original Message-----
From: Hugh McLaughlin [mailto:hugh@k...]
Sent: Friday, June 21, 2002 4:31 PM
To: ASP+
Subject: [aspx] Testing textbox for null
Hello Everyone and thanks for your help in advance. I am working on an
application that builds a SQL query based on whether data has been
entered into a text field. An example is located at:
http://www.famb.org/roster.aspx
Basically, the idea is to check and see if there is data entered into
the
first or last anme fields and build the query accordingly. The code is:
Dim SQL As String =3D "Select * From tblMembers"
If Trim(LastName.Text)<>"" OR Not(IsDBNull(Trim(LastName.Text))) Then
SQL=3DSQL & " WHERE LastName LIKE '" & LastName.Text & "%'"
End If
However, whether I enter data into the last name field or not, the WHERE
clause that should be inserted only if data is present, continues to be
inserted. Obviously, my "If...Then" is not working properly, but I
don't
understand why. Any help would be greatly appreciated. Thanks.
Message #3 by "Hugh McLaughlin" <hugh@k...> on Sat, 22 Jun 2002 00:07:42
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Well actually I think OR is the right way, but I tried AND and received
the same results.
> I believe from a quick look you want to use the [AND} operator not [OR]
because you want to fail if both condition of "" or null are met =3D)
J. Scot
IronSpire Inc.
-----Original Message-----
From: Hugh McLaughlin [mailto:hugh@k...]
Sent: Friday, June 21, 2002 4:31 PM
To: ASP+
Subject: [aspx] Testing textbox for null
Hello Everyone and thanks for your help in advance. I am working on an
application that builds a SQL query based on whether data has been
entered into a text field. An example is located at:
http://www.famb.org/roster.aspx
Basically, the idea is to check and see if there is data entered into
the
first or last anme fields and build the query accordingly. The code is:
Dim SQL As String =3D "Select * From tblMembers"
If Trim(LastName.Text)<>"" OR Not(IsDBNull(Trim(LastName.Text))) Then
SQL=3DSQL & " WHERE LastName LIKE '" & LastName.Text & "%'"
End If
However, whether I enter data into the last name field or not, the WHERE
clause that should be inserted only if data is present, continues to be
inserted. Obviously, my "If...Then" is not working properly, but I
don't
understand why. Any help would be greatly appreciated. Thanks.
Message #4 by "Albert Davis" <albertdavis@h...> on Fri, 21 Jun 2002 23:59:04 -0400
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Try both in a response.write as a boolean condition to get the results, this
will tell you what is going on in the evaluation..
>From: "Hugh McLaughlin" <hugh@k...>
>Reply-To: "ASP+" <aspx@p...>
>To: "ASP+" <aspx@p...>
>Subject: [aspx] RE: Testing textbox for null
>Date: Sat, 22 Jun 2002 00:07:42
>
>Well actually I think OR is the right way, but I tried AND and received
>the same results.
>
> > I believe from a quick look you want to use the [AND} operator not [OR]
>because you want to fail if both condition of "" or null are met =3D)
>
>J. Scot
>IronSpire Inc.
>
>-----Original Message-----
>From: Hugh McLaughlin [mailto:hugh@k...]
>Sent: Friday, June 21, 2002 4:31 PM
>To: ASP+
>Subject: [aspx] Testing textbox for null
>
>
>Hello Everyone and thanks for your help in advance. I am working on an
>application that builds a SQL query based on whether data has been
>entered into a text field. An example is located at:
>
>http://www.famb.org/roster.aspx
>
>Basically, the idea is to check and see if there is data entered into
>the
>first or last anme fields and build the query accordingly. The code is:
>
>Dim SQL As String =3D "Select * From tblMembers"
>
>If Trim(LastName.Text)<>"" OR Not(IsDBNull(Trim(LastName.Text))) Then
> SQL=3DSQL & " WHERE LastName LIKE '" & LastName.Text & "%'"
>End If
>
>However, whether I enter data into the last name field or not, the WHERE
>
>clause that should be inserted only if data is present, continues to be
>inserted. Obviously, my "If...Then" is not working properly, but I
>don't
>understand why. Any help would be greatly appreciated. Thanks.
_________________________________________________________________
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Message #5 by nzulfiqar <nzulfiqar@g...> on Sat, 22 Jun 2002 09:13:46 +0400
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Hi, check the name of last name field. I think may be u r entering value in
last name filed and checking it but control name is FirstName where u r
entering value.
-----Original Message-----
From: Albert Davis [mailto:albertdavis@h...]
Sent: Saturday, June 22, 2002 7:59 AM
To: ASP+
Subject: [aspx] RE: Testing textbox for null
Try both in a response.write as a boolean condition to get the results, this
will tell you what is going on in the evaluation..
>From: "Hugh McLaughlin" <hugh@k...>
>Reply-To: "ASP+" <aspx@p...>
>To: "ASP+" <aspx@p...>
>Subject: [aspx] RE: Testing textbox for null
>Date: Sat, 22 Jun 2002 00:07:42
>
>Well actually I think OR is the right way, but I tried AND and received
>the same results.
>
> > I believe from a quick look you want to use the [AND} operator not [OR]
>because you want to fail if both condition of "" or null are met =3D)
>
>J. Scot
>IronSpire Inc.
>
>-----Original Message-----
>From: Hugh McLaughlin [mailto:hugh@k...]
>Sent: Friday, June 21, 2002 4:31 PM
>To: ASP+
>Subject: [aspx] Testing textbox for null
>
>
>Hello Everyone and thanks for your help in advance. I am working on an
>application that builds a SQL query based on whether data has been
>entered into a text field. An example is located at:
>
>http://www.famb.org/roster.aspx
>
>Basically, the idea is to check and see if there is data entered into
>the
>first or last anme fields and build the query accordingly. The code is:
>
>Dim SQL As String =3D "Select * From tblMembers"
>
>If Trim(LastName.Text)<>"" OR Not(IsDBNull(Trim(LastName.Text))) Then
> SQL=3DSQL & " WHERE LastName LIKE '" & LastName.Text & "%'"
>End If
>
>However, whether I enter data into the last name field or not, the WHERE
>
>clause that should be inserted only if data is present, continues to be
>inserted. Obviously, my "If...Then" is not working properly, but I
>don't
>understand why. Any help would be greatly appreciated. Thanks.
_________________________________________________________________
Send and receive Hotmail on your mobile device: http://mobile.msn.com
Message #6 by "Dave Rezoski" <daverezoski@h...> on Sat, 22 Jun 2002 04:56:15 +0000
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I think you need to check if LastName.Text.Length <= 0
----Original Message Follows----
From: "Hugh McLaughlin" <hugh@k...>
Reply-To: "ASP+" <aspx@p...>
To: "ASP+" <aspx@p...>
Subject: [aspx] RE: Testing textbox for null
Date: Sat, 22 Jun 2002 00:07:42
Well actually I think OR is the right way, but I tried AND and received
the same results.
> I believe from a quick look you want to use the [AND} operator not [OR]
because you want to fail if both condition of "" or null are met =3D)
J. Scot
IronSpire Inc.
-----Original Message-----
From: Hugh McLaughlin [mailto:hugh@k...]
Sent: Friday, June 21, 2002 4:31 PM
To: ASP+
Subject: [aspx] Testing textbox for null
Hello Everyone and thanks for your help in advance. I am working on an
application that builds a SQL query based on whether data has been
entered into a text field. An example is located at:
http://www.famb.org/roster.aspx
Basically, the idea is to check and see if there is data entered into
the
first or last anme fields and build the query accordingly. The code is:
Dim SQL As String =3D "Select * From tblMembers"
If Trim(LastName.Text)<>"" OR Not(IsDBNull(Trim(LastName.Text))) Then
SQL=3DSQL & " WHERE LastName LIKE '" & LastName.Text & "%'"
End If
However, whether I enter data into the last name field or not, the WHERE
clause that should be inserted only if data is present, continues to be
inserted. Obviously, my "If...Then" is not working properly, but I
don't
understand why. Any help would be greatly appreciated. Thanks.
_________________________________________________________________
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Message #7 by "Mingkun Goh" <mangokun@h...> on Sun, 23 Jun 2002 08:46:15
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Just to let you know, the value LastName.Text will not be Null no matter
whether you put in anything in your TextBox LastName.
So it doesn't make sense to test it with IsDBNull function.
Try replacing your if else block with the following (and tell us whether
it works):
If LastName.Text.Trim <> "" Then
SQL = SQL & " WHERE LastName LIKE '" & LastName.Text & "%'"
End If
Just to review your code:
IsDBNull(Trim(LastName.Text)) always evaluate to False
Not(IsDBNull(Trim(LastName.Text))) makes it evaluate to True
So when the code is evaluated as below:
If Trim(LastName.Text)<>"" OR True Then
SQL=SQL & " WHERE LastName LIKE '" & LastName.Text & "%'"
End If
Since the second conditions is always true, the first condition doesn't
make a difference.
Therefore your code is always executed.
Previous message:
Hello Everyone and thanks for your help in advance. I am working on an
application that builds a SQL query based on whether data has been
entered into a text field. An example is located at:
http://www.famb.org/roster.aspx
Basically, the idea is to check and see if there is data entered into the
first or last anme fields and build the query accordingly. The code is:
Dim SQL As String = "Select * From tblMembers"
If Trim(LastName.Text)<>"" OR Not(IsDBNull(Trim(LastName.Text))) Then
SQL=SQL & " WHERE LastName LIKE '" & LastName.Text & "%'"
End If
However, whether I enter data into the last name field or not, the WHERE
clause that should be inserted only if data is present, continues to be
inserted. Obviously, my "If...Then" is not working properly, but I don't
understand why. Any help would be greatly appreciated. Thanks.
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