OleDbDataReader as parameter

[Dion Heskett]

I wish to supply the formating as a parameter, I have tried OleDbDataReader
but get a null ref.
just can't seem to get this to work. I think this has something to do with
ExecuteReader.

also can't seem to use this as the first pram
OleDbDataReader reader = new OleDbDataReader ()

i.e
public static string Read(OleDbDataR eader reader, string query, string
format )

this is what I would like as a parameter if possible. "<p> +
reader["Text"].ToString() + "</p>" + "\n"
//returndata += ("<p> + reader["Text"].ToString() + "</p>" + "\n" );
public static string Read(OleDbDataR eader reader, string query, string
pram3 )
{

OleDbConnection conn = null;
//OleDbDataReader reader = null;
string returndata = null;
try
{
conn = new OleDbConnection (MySite.GlobalS ettings.Connect ionString);
conn.Open();

OleDbCommand cmd = new OleDbCommand(qu ery, conn);
cmd.CommandType = CommandType.Sto redProcedure;
reader = cmd.ExecuteRead er();

while( reader.Read() )
{
//returndata += ("<p> + reader["Text"].ToString() + "</p>" + "\n" );
}
}

// catch (Exception e)
// {
// Response.Write( e.Message);
// Response.End();
// }
finally
{
if (reader != null) reader.Close();
if (conn != null) conn.Close();
}
return returndata;
}

Thanks

Dion

[Neno Loje [MSP]]

Why do you want to pass the DataReader into the method?!?

[William Ryan]

Dion:

In your example, you It doesn't look like you are getting anything from
passing it in. If you declared it locally and returned it, you'd be in the
same place. Problem with a Reader and the way you are using it is that it
needs an open connection to iterate through itself. A reader that can't
talk to the DB can't do anything for you other than throw exceptions. So
you could conciveably return a reader from a method in another class, and
everything it needs could be out of scope / rather, unaccessible.

If you used the same code though, and returned a reader as the Datatype
you'd be in the same boat, although I don't think either will work.

Couldn't you just iterate through the reader and declare it locally, and
just return a string or stringbuilder with all the data formatted?

I probably don't totally understand the methodology, but we can probably get
whatever you want to do to work nonetheless.

Cheers,

Bill
"Dion Heskett" <dh******@llewe llyn.co.uk> wrote in message
news:uT******** ******@TK2MSFTN GP09.phx.gbl...

I wish to supply the formating as a parameter, I have tried OleDbDataReader but get a null ref.
just can't seem to get this to work. I think this has something to do with
ExecuteReader.

also can't seem to use this as the first pram
OleDbDataReader reader = new OleDbDataReader ()

i.e
public static string Read(OleDbDataR eader reader, string query, string
format )

this is what I would like as a parameter if possible. "<p> +
reader["Text"].ToString() + "</p>" + "\n"
//returndata += ("<p> + reader["Text"].ToString() + "</p>" + "\n" );
public static string Read(OleDbDataR eader reader, string query, string
pram3 )
{

OleDbConnection conn = null;
//OleDbDataReader reader = null;
string returndata = null;
try
{
conn = new OleDbConnection (MySite.GlobalS ettings.Connect ionString);
conn.Open();

OleDbCommand cmd = new OleDbCommand(qu ery, conn);
cmd.CommandType = CommandType.Sto redProcedure;
reader = cmd.ExecuteRead er();

while( reader.Read() )
{
//returndata += ("<p> + reader["Text"].ToString() + "</p>" + "\n" );
}
}

// catch (Exception e)
// {
// Response.Write( e.Message);
// Response.End();
// }
finally
{
if (reader != null) reader.Close();
if (conn != null) conn.Close();
}
return returndata;
}

Thanks

Dion

[Dion Heskett]

It if do this then i will need to create this function on every page that i
use it, i'am trying to avoid this.

I have an overloaded version that works for a repeater/datagrid.

all i do is declare a repeater or datagrid object and pass in a control and
query, check if it's a datagrid or repeater and bind, then close the
database connection.
ie Read(repeater1, "MyQuery")

You also say it needs an open connection, the below code opens the DB

conn = new OleDbConnection (MySite.GlobalS ettings.Connect ionString);
conn.Open();
Dion

"William Ryan" <do********@nos pam.comcast.net > wrote in message
news:u4******** ******@TK2MSFTN GP10.phx.gbl...

Dion:

In your example, you It doesn't look like you are getting anything from
passing it in. If you declared it locally and returned it, you'd be in the same place. Problem with a Reader and the way you are using it is that it
needs an open connection to iterate through itself. A reader that can't
talk to the DB can't do anything for you other than throw exceptions. So
you could conciveably return a reader from a method in another class, and
everything it needs could be out of scope / rather, unaccessible.

If you used the same code though, and returned a reader as the Datatype
you'd be in the same boat, although I don't think either will work.

Couldn't you just iterate through the reader and declare it locally, and
just return a string or stringbuilder with all the data formatted?

I probably don't totally understand the methodology, but we can probably get whatever you want to do to work nonetheless.

Cheers,

Bill
"Dion Heskett" <dh******@llewe llyn.co.uk> wrote in message
news:uT******** ******@TK2MSFTN GP09.phx.gbl...

I wish to supply the formating as a parameter, I have tried

OleDbDataReader

but get a null ref.
just can't seem to get this to work. I think this has something to do with ExecuteReader.

also can't seem to use this as the first pram
OleDbDataReader reader = new OleDbDataReader ()

i.e
public static string Read(OleDbDataR eader reader, string query, string
format )

this is what I would like as a parameter if possible. "<p> +
reader["Text"].ToString() + "</p>" + "\n"
//returndata += ("<p> + reader["Text"].ToString() + "</p>" + "\n" );
public static string Read(OleDbDataR eader reader, string query, string
pram3 )
{

OleDbConnection conn = null;
//OleDbDataReader reader = null;
string returndata = null;
try
{
conn = new OleDbConnection (MySite.GlobalS ettings.Connect ionString);
conn.Open();

OleDbCommand cmd = new OleDbCommand(qu ery, conn);
cmd.CommandType = CommandType.Sto redProcedure;
reader = cmd.ExecuteRead er();

while( reader.Read() )
{
//returndata += ("<p> + reader["Text"].ToString() + "</p>" + "\n" ); }
}

// catch (Exception e)
// {
// Response.Write( e.Message);
// Response.End();
// }
finally
{
if (reader != null) reader.Close();
if (conn != null) conn.Close();
}
return returndata;
}

Thanks

Dion

[Dion Heskett]

So i can access the reader["Fields"]

"Neno Loje [MSP]" <ne*******@neno loje.de> wrote in message
news:uE******** ******@TK2MSFTN GP10.phx.gbl...

Why do you want to pass the DataReader into the method?!?

[Kevin Yu]

Hi Dion,

I'm still not sure why you pass this OleDbDataReader parameter to the
function. Because you didn't use it in the Read() function but assigned a
value to it. This can only result in exceptions. Did you get any error
messages? I recommend you to declare this DataReader locally, so that it
might work. Here's a code example:

public string Read(string query, string pram3 )
{

OleDbConnection conn = null;
//OleDbDataReader reader = null;
string returndata = null;
try
{
conn = new OleDbConnection (MySite.GlobalS ettings.Connect ionString);
conn.Open();

OleDbCommand cmd = new OleDbCommand(qu ery, conn);
//cmd.CommandType = CommandType.Tex t;
OleDbDataReader reader = cmd.ExecuteRead er();

while( reader.Read() )
{
//returndata += ("<p> + reader["Text"].ToString() + "</p>" + "\n" );
}
}
catch (Exception e)
{
Response.Write( e.Message);
Response.End();
}
finally
{
if (reader != null) reader.Close();
if (conn != null) conn.Close();
}
return returndata;
}
If anything is unclear, please feel free to reply to the post.

Kevin Yu
=======
"This posting is provided "AS IS" with no warranties, and confers no
rights."

[Dion Heskett]

Ok now i get

An object reference is required for the nonstatic filed, method or property
reader
public OleDbDataReader reader = null;
Read("qryNews", reader["Text"].ToString());
private static string Read(string query, string pramx)
{
OleDbConnection conn = null;
//OleDbDataReader reader = null;
try
{
conn = new OleDbConnection ("Provider=Micr osoft.Jet.OLEDB .4.0; Data
Source=MyDataba se.mdb");
conn.Open();

OleDbCommand cmd = new OleDbCommand(qu ery, conn);
cmd.CommandType = CommandType.Sto redProcedure;

reader = cmd.ExecuteRead er();

while (reader.Read())
{
returndata += (pramx);
}

}
finally
{
if (reader != null) reader.Close();
if (conn != null) conn.Close();
}
return returndata;
}

"Kevin Yu" <v-****@online.mic rosoft.com> wrote in message
news:jE******** *****@cpmsftngx a06.phx.gbl...

Hi Dion,

I'm still not sure why you pass this OleDbDataReader parameter to the
function. Because you didn't use it in the Read() function but assigned a
value to it. This can only result in exceptions. Did you get any error
messages? I recommend you to declare this DataReader locally, so that it
might work. Here's a code example:

public string Read(string query, string pram3 )
{

OleDbConnection conn = null;
//OleDbDataReader reader = null;
string returndata = null;
try
{
conn = new OleDbConnection (MySite.GlobalS ettings.Connect ionString);
conn.Open();

OleDbCommand cmd = new OleDbCommand(qu ery, conn);
//cmd.CommandType = CommandType.Tex t;
OleDbDataReader reader = cmd.ExecuteRead er();

while( reader.Read() )
{
//returndata += ("<p> + reader["Text"].ToString() + "</p>" + "\n" );
}
}
catch (Exception e)
{
Response.Write( e.Message);
Response.End();
}
finally
{
if (reader != null) reader.Close();
if (conn != null) conn.Close();
}
return returndata;
}
If anything is unclear, please feel free to reply to the post.

Kevin Yu
=======
"This posting is provided "AS IS" with no warranties, and confers no
rights."

[Kevin Yu]

Hi Dion,

Your code of Read() works fine on my computer. In your post, you got an "An
object reference is required for the nonstatic filed, method or property
reader" error message in your program. Would you please tell me on which
statement did this error occur?

I noticed these two statements in your code.

public OleDbDataReader reader = null;
Read("qryNews", reader["Text"].ToString());

Which function are these two lines located? If you run these two statements
a NullReferenceEx ception will be thrown, because the reader didn't refer to
any object.

If anything is unclear, please feel free to reply to the post.

Kevin Yu
=======
"This posting is provided "AS IS" with no warranties, and confers no
rights."

[Dion Heskett]

Did you see the attached code ?

when GlobalSettings. Read("qryNews", reader["Text"].ToString()); from
WebForm1.aspx.c s
is compile I get this.

The name 'reader' does not exist in the class or nameapace.

This is because the function does not know anything about the reader, it not
created untill
reader = cmd.ExecuteRead er(); is called in the GlobalSettings. Read()
function located in
GlobalSettings. cs file.

How do access pass in the the reader and access this information in a static
function ? is this even possible !

Thnaks

Dion
"Kevin Yu" <v-****@online.mic rosoft.com> wrote in message
news:hV******** ******@cpmsftng xa06.phx.gbl...

Hi Dion,

Your code of Read() works fine on my computer. In your post, you got an "An object reference is required for the nonstatic filed, method or property
reader" error message in your program. Would you please tell me on which
statement did this error occur?

I noticed these two statements in your code.

public OleDbDataReader reader = null;
Read("qryNews", reader["Text"].ToString());
Which function are these two lines located? If you run these two

statements a NullReferenceEx ception will be thrown, because the reader didn't refer to any object.

If anything is unclear, please feel free to reply to the post.

Kevin Yu
=======
"This posting is provided "AS IS" with no warranties, and confers no
rights."

[Kevin Yu]

Hi Dion,

I've read all the attached codes. If you want to access the static member
of a class, you have to specify the class name of it. For example,
GloabalSettings .reader. Before you call GlobalSettings. Read(), you have to
assign initial value to GlobalSettings. reader. Or a NullReferenceEx ception
will be thrown. You can initialize the GlobalSettings. reader like the
following:

if(this.oleDbCo nnection1.State == ConnectionState .Closed)
this.oleDbConne ction1.Open();
OleDbCommand cmd = new OleDbCommand();
cmd.CommandText = "SELECT * FROM Table1";
cmd.Connection = this.oleDbConne ction1;
GlobalSettings. reader = cmd.ExecuteRead er();
reader.Read();
MySite.GlobalSe ttings.Read("qr yNews",
GlobalSettings. reader["Text"].ToString());

If anything is unclear, please feel free to reply to the post.

Kevin Yu
=======
"This posting is provided "AS IS" with no warranties, and confers no
rights."