Conversion from type 'DBNull' to type 'String' is not valid

[Chris]

Hi again,

I want to read all the records of a table with 2 fields.
The problem is that some records have null value in the second field.
This code below works when all records have both fields fiilled, but gives
the error:
"Conversion from type 'DBNull' to type 'String' is not valid" when not.

.....
comd = New System.Data.OleDb.OleDbCommand("select name,lok from pc",
oConnection)
dtreader = comd.ExecuteReader
for i=0 to 41
dtreader.Read()
for j=0 to 1
f=dtreader.item(j)
Response.Write(f)
next
Response.Write("<br>")
next
dtreader.Close()

Thanks for hints.
Chris

[sloan]

You can either check for

IsDBNULL before setting it.

if ( !myDataReader.IsDBNull ( 0 ) )
{
string x = myDataReader.GetString(0);
}
Or you can find the SafeDataReader .. a class to help with this.
(google it, but its in vb.net)

"Chris" <cc*@sdsd.dc> wrote in message
news:uW**************@TK2MSFTNGP05.phx.gbl...

Hi again,

I want to read all the records of a table with 2 fields.
The problem is that some records have null value in the second field.
This code below works when all records have both fields fiilled, but gives
the error:
"Conversion from type 'DBNull' to type 'String' is not valid" when not.

....
comd = New System.Data.OleDb.OleDbCommand("select name,lok from pc",
oConnection)
dtreader = comd.ExecuteReader
for i=0 to 41
dtreader.Read()
for j=0 to 1
f=dtreader.item(j)
Response.Write(f)
next
Response.Write("<br>")
next
dtreader.Close()

Thanks for hints.
Chris

[Chris]

Thanks

"sloan" <sl***@ipass.net> wrote in message
news:e4**************@TK2MSFTNGP04.phx.gbl...

You can either check for

IsDBNULL before setting it.

if ( !myDataReader.IsDBNull ( 0 ) )
{
string x = myDataReader.GetString(0);
}
Or you can find the SafeDataReader .. a class to help with this.
(google it, but its in vb.net)

"Chris" <cc*@sdsd.dc> wrote in message
news:uW**************@TK2MSFTNGP05.phx.gbl...

Hi again,

I want to read all the records of a table with 2 fields.
The problem is that some records have null value in the second field.
This code below works when all records have both fields fiilled, but gives the error:
"Conversion from type 'DBNull' to type 'String' is not valid" when not.

....
comd = New System.Data.OleDb.OleDbCommand("select name,lok from pc",
oConnection)
dtreader = comd.ExecuteReader
for i=0 to 41
dtreader.Read()
for j=0 to 1
f=dtreader.item(j)
Response.Write(f)
next
Response.Write("<br>")
next
dtreader.Close()

Thanks for hints.
Chris