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Object reference not set to an instance of an object

SP
Hello All,

I have a web method in a web service as follows:

[WebMethod]
public SqlDataReader Display_test_data()
{

string connectionInfo =
ConfigurationSettings.AppSettings["ConnectionInfo"];
SqlConnection sqlconnection = new SqlConnection(connectionInfo);
sqlconnection.Open();

SqlCommand cmd_sql = new SqlCommand("select * from
Test",sqlconnection);
SqlDataReader rdr_sql = cmd_sql.ExecuteReader();

return rdr_sql;

}

This method return the error "Object reference not set to an instance
of an object" when the return type is SqlDataReader.

Instead if I have a return type as int ti work fine.

Any pointers or tips.

Regards,

Nov 23 '05 #1
2 6526
You can return a datareader via a webmethod. A datareader is an open
connection to your database that you can't return via a webmethod to your
client. Instead you can populate a dataset which holds a disconnected
version of you data. Because of its disconnected nature, the dataset can be
returned via webmethod.

Peter kelcey

"SP" <sp*******@hotmail.com> wrote in message
news:11**********************@g44g2000cwa.googlegr oups.com...
Hello All,

I have a web method in a web service as follows:

[WebMethod]
public SqlDataReader Display_test_data()
{

string connectionInfo =
ConfigurationSettings.AppSettings["ConnectionInfo"];
SqlConnection sqlconnection = new SqlConnection(connectionInfo);
sqlconnection.Open();

SqlCommand cmd_sql = new SqlCommand("select * from
Test",sqlconnection);
SqlDataReader rdr_sql = cmd_sql.ExecuteReader();

return rdr_sql;

}

This method return the error "Object reference not set to an instance
of an object" when the return type is SqlDataReader.

Instead if I have a return type as int ti work fine.

Any pointers or tips.

Regards,

Nov 23 '05 #2
Sorry, posted that last message with a typo. The first line should read
"you CAN'T return a datareader via a webmethod"

Peter Kelcey (change the AT and DOT for the real address) wrote:
You can return a datareader via a webmethod. A datareader is an open
connection to your database that you can't return via a webmethod to your
client. Instead you can populate a dataset which holds a disconnected
version of you data. Because of its disconnected nature, the dataset can be
returned via webmethod.

Peter kelcey

"SP" <sp*******@hotmail.com> wrote in message
news:11**********************@g44g2000cwa.googlegr oups.com...
Hello All,

I have a web method in a web service as follows:

[WebMethod]
public SqlDataReader Display_test_data()
{

string connectionInfo =
ConfigurationSettings.AppSettings["ConnectionInfo"];
SqlConnection sqlconnection = new SqlConnection(connectionInfo);
sqlconnection.Open();

SqlCommand cmd_sql = new SqlCommand("select * from
Test",sqlconnection);
SqlDataReader rdr_sql = cmd_sql.ExecuteReader();

return rdr_sql;

}

This method return the error "Object reference not set to an instance
of an object" when the return type is SqlDataReader.

Instead if I have a return type as int ti work fine.

Any pointers or tips.

Regards,


Nov 23 '05 #3

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