Invalid attempt to read when no data is present

[=?Utf-8?B?ZWdzZGFy?=]

How can I solve this error:
Invalid attempt to read when no data is present.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information about
the error and where it originated in the code.

Exception Details: System.InvalidOperationException: Invalid attempt to read
when no data is present.

Source Error:
Line 42: Dim rs As SqlDataReader = sqlCmd.ExecuteReader()
Line 43: rs.Read()
Line 44: Response.Write(rs("Nombre"))
Line 45: Response.End()
Line 46: %>

This is my code:

Dim sqlConn As SqlConnection
Dim sqlCmd As SqlCommand
Dim strConnection, resul As String
strConnection =
ConfigurationManager.ConnectionStrings("SIPconnect ionstring").ConnectionString
sqlConn = New SqlConnection(strConnection)
sqlCmd = New SqlCommand("Select * from documentos where
idpropuesta='" & Request.QueryString("mivar") & "'", sqlConn)

sqlConn.Open()

resul = sqlCmd.ExecuteNonQuery
Dim rs As SqlDataReader = sqlCmd.ExecuteReader()
rs.Read()
Response.Write(rs("Nombre"))

[Mark Rae [MVP]]

"egsdar" <eg****@discussions.microsoft.comwrote in message
news:2C**********************************@microsof t.com...

How can I solve this error:

By using an SQL statement which returns data.

Select * from documentos where idpropuesta='" &
Request.QueryString("mivar")

For whatever reason, the above SQL statement does not return any rows,
almost certainly because Request.QueryString is incorrect.

Also, it's important that you realise that you are wide open to SQL
Injection - Google it...

What would happen if someone modified the URL manually to change the
querystring as follows...

http://www.mysite.com/mypage.aspx?mivar=1;DELETE FROM documentos
--
Mark Rae
ASP.NET MVP
http://www.markrae.net

[=?Utf-8?B?ZWdzZGFy?=]

Yes, you're right about the SQL injection, however I have to focus on the
results, then I'll create stored procedures to help me on that, the thing is
that i have to present this tomorrow and I don't have to much time.
The query is fine I already test and it brings data if I use it in the sql
query.
So, what's wrong?
"Mark Rae [MVP]" wrote:

"egsdar" <eg****@discussions.microsoft.comwrote in message
news:2C**********************************@microsof t.com...

How can I solve this error:

By using an SQL statement which returns data.

Select * from documentos where idpropuesta='" &
Request.QueryString("mivar")

For whatever reason, the above SQL statement does not return any rows,
almost certainly because Request.QueryString is incorrect.

Also, it's important that you realise that you are wide open to SQL
Injection - Google it...

What would happen if someone modified the URL manually to change the
querystring as follows...

http://www.mysite.com/mypage.aspx?mivar=1;DELETE FROM documentos
--
Mark Rae
ASP.NET MVP
http://www.markrae.net

[Mark Rae [MVP]]

"egsdar" <eg****@discussions.microsoft.comwrote in message
news:78**********************************@microsof t.com...

>For whatever reason, the above SQL statement does not return any rows,
almost certainly because Request.QueryString is incorrect.

The query is fine I already test and it brings data if I use it in the sql
query.

So, what's wrong?

It's not returning any data.

Run a SQL trace and inspect what's *actually* being sent to SQL Server...
--
Mark Rae
ASP.NET MVP
http://www.markrae.net

[bruce barker]

not sure why the ExecuteNonQuery followed by ExcuteReader which will run
the query twice.

the rs.Read() return true or false depending on whether a row was read
or not. if false, then accessing row data will throw an error.

-- bruce (sqlwork.com)

egsdar wrote:

How can I solve this error:
Invalid attempt to read when no data is present.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information about
the error and where it originated in the code.

Exception Details: System.InvalidOperationException: Invalid attempt to read
when no data is present.

Source Error:
Line 42: Dim rs As SqlDataReader = sqlCmd.ExecuteReader()
Line 43: rs.Read()
Line 44: Response.Write(rs("Nombre"))
Line 45: Response.End()
Line 46: %>

This is my code:

Dim sqlConn As SqlConnection
Dim sqlCmd As SqlCommand
Dim strConnection, resul As String
strConnection =
ConfigurationManager.ConnectionStrings("SIPconnect ionstring").ConnectionString
sqlConn = New SqlConnection(strConnection)
sqlCmd = New SqlCommand("Select * from documentos where
idpropuesta='" & Request.QueryString("mivar") & "'", sqlConn)

sqlConn.Open()

resul = sqlCmd.ExecuteNonQuery
Dim rs As SqlDataReader = sqlCmd.ExecuteReader()
rs.Read()
Response.Write(rs("Nombre"))

[=?Utf-8?B?ZWdzZGFy?=]

Actually, when I run the same query in the SQL Query Analyzer brings data.
"Mark Rae [MVP]" wrote:

"egsdar" <eg****@discussions.microsoft.comwrote in message
news:78**********************************@microsof t.com...

For whatever reason, the above SQL statement does not return any rows,
almost certainly because Request.QueryString is incorrect.

The query is fine I already test and it brings data if I use it in the sql
query.

So, what's wrong?

It's not returning any data.

Run a SQL trace and inspect what's *actually* being sent to SQL Server...
--
Mark Rae
ASP.NET MVP
http://www.markrae.net

[Mark Rae [MVP]]

"egsdar" <eg****@discussions.microsoft.comwrote in message
news:25**********************************@microsof t.com...

>>>For whatever reason, the above SQL statement does not return any rows,
almost certainly because Request.QueryString is incorrect.

The query is fine I already test and it brings data if I use it in the
sql
query.

So, what's wrong?

It's not returning any data.

Run a SQL trace and inspect what's *actually* being sent to SQL Server...

Actually, when I run the same query in the SQL Query Analyzer brings data.

I'm sure it does. However, that's not what I asked you to do...

You need to run a SQL trace. This will allow you to inspect what is
*actually* being sent to the SQL Server, irrespective of what you think is
being sent, or what you think should be sent.

Also, following up on Bruce's reply, is there any reason that you're doing
this:

resul = sqlCmd.ExecuteNonQuery
Dim rs As SqlDataReader = sqlCmd.ExecuteReader()

ExecuteNonQuery is used specifically to send commands to a database which
*DON'T* return any records e.g. INSERTs, UPDATEs, DELETEs, DDL etc.
http://msdn.microsoft.com/en-us/libr...enonquery.aspx
What is its purpose here?

See here: http://msdn.microsoft.com/en-us/library/9kcbe65k.aspx for an
example of how to return a DataReader - there is no mention of
ExecuteNonQuery...
--
Mark Rae
ASP.NET MVP
http://www.markrae.net