The following code raises the error "Specified cast is not valid."
MembershipUser user = Membership.GetU ser(userId);
DataSet ds = DataLayer.ExecQ ueryData("SELEC T * FROM mc_Clients WHERE
UserId='" + userId.ToString () + "'");
if (ds == null || ds.Tables.Count == 0 || ds.Tables[0].Rows.Count == 0)
return null;
ClientEx client = new ClientEx();
client.ClientDa ta = new Client();
client.ClientDa ta.Email = user.UserName;
client.ClientDa ta.UserID = user.ProviderUs erKey;
client.ClientDa ta.LastLogin = user.LastLoginD ate;
DataRow dr = ds.Tables[0].Rows[0];
// ...
if (!Convert.IsDBN ull(dr["Sex"]))
client.Sex = (int)dr["Sex"]; <<== ERROR HERE!
// ...
In the database table, Sex has a data type=smallint and nullable=True, and
client.Sex has a data type of int.
If I attempt to examine the contents of dr["Sex"] in the debugger, it shows
a value of 0x0000. If I attempt to examine the contents of (int)dr["Sex"] in
the debugger, it shows an error about not being able to unbox (sorry I no
longer have the exact text).
Any suggestions?
--
Jonathan Wood
SoftCircuits Programming http://www.softcircuits.com 38  2021 
"Jonathan Wood" <jw***@softcirc uits.comwrote in message
news:%2******** **********@TK2M SFTNGP04.phx.gb l...
The following code raises the error "Specified cast is not valid."
Yes, it would do...
if (!Convert.IsDBN ull(dr["Sex"]))
if (dr["Sex"] != DBNull.Value)
In the database table, Sex has a data type=smallint
So the Sex field can have a range of values from -32,768 to 32,767...? http://msdn2.microsoft.com/en-us/lib...8(SQL.80).aspx
--
Mark Rae
ASP.NET MVP http://www.markrae.net
What type is client.Sex? Looks like whatever it is, it cannot accept int as a
value. Unless the Convert of the (int)dr["Sex"] is failing because it
itself is not an integer.
-- Peter
Site: http://www.eggheadcafe.com
UnBlog: http://petesbloggerama.blogspot.com
MetaFinder: http://www.blogmetafinder.com
"Jonathan Wood" wrote:
The following code raises the error "Specified cast is not valid."
MembershipUser user = Membership.GetU ser(userId);
DataSet ds = DataLayer.ExecQ ueryData("SELEC T * FROM mc_Clients WHERE
UserId='" + userId.ToString () + "'");
if (ds == null || ds.Tables.Count == 0 || ds.Tables[0].Rows.Count == 0)
return null;
ClientEx client = new ClientEx();
client.ClientDa ta = new Client();
client.ClientDa ta.Email = user.UserName;
client.ClientDa ta.UserID = user.ProviderUs erKey;
client.ClientDa ta.LastLogin = user.LastLoginD ate;
DataRow dr = ds.Tables[0].Rows[0];
// ...
if (!Convert.IsDBN ull(dr["Sex"]))
client.Sex = (int)dr["Sex"]; <<== ERROR HERE!
// ...
In the database table, Sex has a data type=smallint and nullable=True, and
client.Sex has a data type of int.
If I attempt to examine the contents of dr["Sex"] in the debugger, it shows
a value of 0x0000. If I attempt to examine the contents of (int)dr["Sex"] in
the debugger, it shows an error about not being able to unbox (sorry I no
longer have the exact text).
Any suggestions?
--
Jonathan Wood
SoftCircuits Programming
http://www.softcircuits.com
As stated, client.Sex is an int.
--
Jonathan Wood
SoftCircuits Programming http://www.softcircuits.com
"Peter Bromberg [C# MVP]" <pb*******@yaho o.NoSpamMaam.co mwrote in message
news:23******** *************** ***********@mic rosoft.com...
What type is client.Sex? Looks like whatever it is, it cannot accept int
as a
value. Unless the Convert of the (int)dr["Sex"] is failing because it
itself is not an integer.
-- Peter
Site: http://www.eggheadcafe.com
UnBlog: http://petesbloggerama.blogspot.com
MetaFinder: http://www.blogmetafinder.com
"Jonathan Wood" wrote:
>The following code raises the error "Specified cast is not valid."
MembershipUser user = Membership.GetU ser(userId);
DataSet ds = DataLayer.ExecQ ueryData("SELEC T * FROM mc_Clients WHERE
UserId='" + userId.ToString () + "'");
if (ds == null || ds.Tables.Count == 0 || ds.Tables[0].Rows.Count ==
0)
return null;
ClientEx client = new ClientEx();
client.ClientDa ta = new Client();
client.ClientDa ta.Email = user.UserName;
client.ClientDa ta.UserID = user.ProviderUs erKey;
client.ClientDa ta.LastLogin = user.LastLoginD ate;
DataRow dr = ds.Tables[0].Rows[0];
// ...
if (!Convert.IsDBN ull(dr["Sex"]))
client.Sex = (int)dr["Sex"]; <<== ERROR HERE!
// ...
In the database table, Sex has a data type=smallint and nullable=True,
and
client.Sex has a data type of int.
If I attempt to examine the contents of dr["Sex"] in the debugger, it
shows
a value of 0x0000. If I attempt to examine the contents of (int)dr["Sex"]
in
the debugger, it shows an error about not being able to unbox (sorry I no
longer have the exact text).
Any suggestions?
--
Jonathan Wood
SoftCircuits Programming
http://www.softcircuits.com
Mark,
>The following code raises the error "Specified cast is not valid."
Yes, it would do...
> if (!Convert.IsDBN ull(dr["Sex"]))
if (dr["Sex"] != DBNull.Value)
So what does that mean? Does that mean dr["Sex"] was, in fact, null but my
check was wrong? And what the heck does Convert.IsDBNul l() do? This seemed
to work on some other fields.
Actually, I just tried this:
if (dr["Sex"] != DBNull.Value)
client.Sex = (int)dr["Sex"];
And I seem to get exactly the same error on the same line.
>In the database table, Sex has a data type=smallint
So the Sex field can have a range of values from -32,768 to 32,767...?
Hey, we like our site to support all types. ;-) Seriously, it's coming from
a RadioButtonList and just seemed to make more sense to use an int. Besides,
I don't see how a database can store a bit field using less than a byte
anyway.
--
Jonathan Wood
SoftCircuits Programming http://www.softcircuits.com
Actually, it looks like dr["Sex"] was NULL. But I thought I was testing for
that.
--
Jonathan Wood
SoftCircuits Programming http://www.softcircuits.com
"Peter Bromberg [C# MVP]" <pb*******@yaho o.NoSpamMaam.co mwrote in message
news:23******** *************** ***********@mic rosoft.com...
What type is client.Sex? Looks like whatever it is, it cannot accept int
as a
value. Unless the Convert of the (int)dr["Sex"] is failing because it
itself is not an integer.
-- Peter
Site: http://www.eggheadcafe.com
UnBlog: http://petesbloggerama.blogspot.com
MetaFinder: http://www.blogmetafinder.com
"Jonathan Wood" wrote:
>The following code raises the error "Specified cast is not valid."
MembershipUser user = Membership.GetU ser(userId);
DataSet ds = DataLayer.ExecQ ueryData("SELEC T * FROM mc_Clients WHERE
UserId='" + userId.ToString () + "'");
if (ds == null || ds.Tables.Count == 0 || ds.Tables[0].Rows.Count ==
0)
return null;
ClientEx client = new ClientEx();
client.ClientDa ta = new Client();
client.ClientDa ta.Email = user.UserName;
client.ClientDa ta.UserID = user.ProviderUs erKey;
client.ClientDa ta.LastLogin = user.LastLoginD ate;
DataRow dr = ds.Tables[0].Rows[0];
// ...
if (!Convert.IsDBN ull(dr["Sex"]))
client.Sex = (int)dr["Sex"]; <<== ERROR HERE!
// ...
In the database table, Sex has a data type=smallint and nullable=True,
and
client.Sex has a data type of int.
If I attempt to examine the contents of dr["Sex"] in the debugger, it
shows
a value of 0x0000. If I attempt to examine the contents of (int)dr["Sex"]
in
the debugger, it shows an error about not being able to unbox (sorry I no
longer have the exact text).
Any suggestions?
--
Jonathan Wood
SoftCircuits Programming
http://www.softcircuits.com
"Jonathan Wood" <jw***@softcirc uits.comwrote in message
news:u4******** **********@TK2M SFTNGP03.phx.gb l...
>>The following code raises the error "Specified cast is not valid."
Yes, it would do...
>> if (!Convert.IsDBN ull(dr["Sex"]))
if (dr["Sex"] != DBNull.Value)
So what does that mean? Does that mean dr["Sex"] was, in fact, null but my
check was wrong?
I believe so...
And what the heck does Convert.IsDBNul l() do? This seemed to work on some
other fields.
It (supposedly) does exactly the same thing: http://msdn2.microsoft.com/en-us/lib....isdbnull.aspx
but I've found it to be an extremely unreliable way of checking for a null
value in a database field...
Actually, I just tried this:
if (dr["Sex"] != DBNull.Value)
client.Sex = (int)dr["Sex"];
And I seem to get exactly the same error on the same line.
Hmm - OK... Set a breakpoint on the first line above and, in the Immediate
window, inspect dr["Sex"]
>>In the database table, Sex has a data type=smallint
So the Sex field can have a range of values from -32,768 to 32,767...?
Hey, we like our site to support all types. ;-) Seriously, it's coming
from a RadioButtonList and just seemed to make more sense to use an int.
I don't understand the thinking behind that at all...
Besides, I don't see how a database can store a bit field using less than
a byte anyway.
SQL Server (and several other RDBMS) can: http://msdn2.microsoft.com/en-us/lib...atype.bit.aspx
My slightly tongue-in-cheek point was that you're using a larger datatype
than is necessary... For gender, I tend to use char(1)...
--
Mark Rae
ASP.NET MVP http://www.markrae.net
I figured this out. It only works if I cast using (short) insteat of (int).
I have no idea why that is--converting from a 16-bit integer to a 32-bit
integer is a trivial task, in fact one that the compiler still does after my
change.
--
Jonathan Wood
SoftCircuits Programming http://www.softcircuits.com
"Jonathan Wood" <jw***@softcirc uits.comwrote in message
news:%2******** **********@TK2M SFTNGP04.phx.gb l...
The following code raises the error "Specified cast is not valid."
MembershipUser user = Membership.GetU ser(userId);
DataSet ds = DataLayer.ExecQ ueryData("SELEC T * FROM mc_Clients WHERE
UserId='" + userId.ToString () + "'");
if (ds == null || ds.Tables.Count == 0 || ds.Tables[0].Rows.Count == 0)
return null;
ClientEx client = new ClientEx();
client.ClientDa ta = new Client();
client.ClientDa ta.Email = user.UserName;
client.ClientDa ta.UserID = user.ProviderUs erKey;
client.ClientDa ta.LastLogin = user.LastLoginD ate;
DataRow dr = ds.Tables[0].Rows[0];
// ...
if (!Convert.IsDBN ull(dr["Sex"]))
client.Sex = (int)dr["Sex"]; <<== ERROR HERE!
// ...
In the database table, Sex has a data type=smallint and nullable=True, and
client.Sex has a data type of int.
If I attempt to examine the contents of dr["Sex"] in the debugger, it
shows a value of 0x0000. If I attempt to examine the contents of
(int)dr["Sex"] in the debugger, it shows an error about not being able to
unbox (sorry I no longer have the exact text).
Any suggestions?
--
Jonathan Wood
SoftCircuits Programming
http://www.softcircuits.com
Mark,
>And I seem to get exactly the same error on the same line.
Hmm - OK... Set a breakpoint on the first line above and, in the Immediate
window, inspect dr["Sex"]
I described that in my original post. At any rate, the fix was to type cast
to a short instead of an int, which doesn't seem like it should be the case.
>Besides, I don't see how a database can store a bit field using less than
a byte anyway.
SQL Server (and several other RDBMS) can:
http://msdn2.microsoft.com/en-us/lib...atype.bit.aspx
My slightly tongue-in-cheek point was that you're using a larger datatype
than is necessary... For gender, I tend to use char(1)...
I didn't see where that link talked about the actual amount of storage used
to store bits in the database, I suppose it's possible to optimize bit
fields if they are stored contiguously, rather than with the other fields in
the same row, but I wouldn't have thought that's how it's done. At any rate,
I've used both char(1) and bit but I'm more comfortable using smallint in
this particular case.
--
Jonathan Wood
SoftCircuits Programming http://www.softcircuits.com
"Jonathan Wood" <jw***@softcirc uits.comwrote in message
news:uZ******** ******@TK2MSFTN GP05.phx.gbl...
Perhaps a byte would be better
Yes it would - or a char(1)...
isn't that a tinyint?
Yes - a tinyint and a char(1) both occupy one byte...
a single byte is the least amount of storage space that most fields could
occupy.
Correct, apart from bit fields for boolean values, but that doesn't apply
here...
--
Mark Rae
ASP.NET MVP http://www.markrae.net This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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