Hi,

I have the following procedure below:
I am getting 2 errors on compile:

Argument '2': cannot convert from 'System.Data.SqlClient.SqlDataReader' to
'ref System.Data.SqlClient.SqlDataReader'

Argument '3': cannot convert from 'System.Text.StringBuilder' to 'ref
System.Text.StringBuilder'

the PrintChildrenRecursive is a class in a referenced DLL that was written in
VB.NET.

this function takes a dataset and loops through it creating a javastring
using stringbuilder that creates a parent-child tree of html hyperlinks.

the printchildrecursive function accepts the Dr and Sbuilder ByReference.

private static void PrintFromRoot(SqlDataReader Dr, StringBuilder SBuilder)
{
PrintChildren PCR = new PrintChildren();

SBuilder.Append("[");
PCR.PrintChildrenRecursive(1, Dr, SBuilder, false);

SBuilder.Remove(1,2); //remove comma and bracket from beginning of string

SBuilder.Append("];");
}

I don't understand why conversion is occuring because they are already of
the correct type as already indicated by the error messages.

thanks

Chris

Chris,

You are passing parameters by reference. In order to do so, you need to
use the ref keyword, like this:

obj.PrintFromRoot(ref sqlDataReader, ref stringBuilder);

Hope this helps.


--
- Nicholas Paldino [.NET/C# MVP]
- (E-Mail Removed)

"Chris" <(E-Mail Removed)> wrote in message
news:793DB326-36D6-4619-95FF-(E-Mail Removed)...
> Hi,
>
> I have the following procedure below:
> I am getting 2 errors on compile:
>
> Argument '2': cannot convert from 'System.Data.SqlClient.SqlDataReader' to
> 'ref System.Data.SqlClient.SqlDataReader'
>
> Argument '3': cannot convert from 'System.Text.StringBuilder' to 'ref
> System.Text.StringBuilder'
>
> the PrintChildrenRecursive is a class in a referenced DLL that was written
> in
> VB.NET.
>
> this function takes a dataset and loops through it creating a javastring
> using stringbuilder that creates a parent-child tree of html hyperlinks.
>
> the printchildrecursive function accepts the Dr and Sbuilder ByReference.
>
> private static void PrintFromRoot(SqlDataReader Dr, StringBuilder
> SBuilder)
> {
> PrintChildren PCR = new PrintChildren();
>
> SBuilder.Append("[");
> PCR.PrintChildrenRecursive(1, Dr, SBuilder, false);
>
> SBuilder.Remove(1,2); //remove comma and bracket from beginning of string
>
> SBuilder.Append("];");
> }
>
> I don't understand why conversion is occuring because they are already of
> the correct type as already indicated by the error messages.
>
> thanks
>
> Chris

Nicholas,

thank you so much!

"Nicholas Paldino [.NET/C# MVP]" wrote:

> Chris,
>
> You are passing parameters by reference. In order to do so, you need to
> use the ref keyword, like this:
>
> obj.PrintFromRoot(ref sqlDataReader, ref stringBuilder);
>
> Hope this helps.
>
>
> --
> - Nicholas Paldino [.NET/C# MVP]
> - (E-Mail Removed)
>
> "Chris" <(E-Mail Removed)> wrote in message
> news:793DB326-36D6-4619-95FF-(E-Mail Removed)...
> > Hi,
> >
> > I have the following procedure below:
> > I am getting 2 errors on compile:
> >
> > Argument '2': cannot convert from 'System.Data.SqlClient.SqlDataReader' to
> > 'ref System.Data.SqlClient.SqlDataReader'
> >
> > Argument '3': cannot convert from 'System.Text.StringBuilder' to 'ref
> > System.Text.StringBuilder'
> >
> > the PrintChildrenRecursive is a class in a referenced DLL that was written
> > in
> > VB.NET.
> >
> > this function takes a dataset and loops through it creating a javastring
> > using stringbuilder that creates a parent-child tree of html hyperlinks.
> >
> > the printchildrecursive function accepts the Dr and Sbuilder ByReference.
> >
> > private static void PrintFromRoot(SqlDataReader Dr, StringBuilder
> > SBuilder)
> > {
> > PrintChildren PCR = new PrintChildren();
> >
> > SBuilder.Append("[");
> > PCR.PrintChildrenRecursive(1, Dr, SBuilder, false);
> >
> > SBuilder.Remove(1,2); //remove comma and bracket from beginning of string
> >
> > SBuilder.Append("];");
> > }
> >
> > I don't understand why conversion is occuring because they are already of
> > the correct type as already indicated by the error messages.
> >
> > thanks
> >
> > Chris
>
>
>

Chris <(E-Mail Removed)> wrote:
> Nicholas,
>
> thank you so much!

Note, however, that you very rarely really want to pass a StringBuilder
or a SqlDataReader by reference. Seeing code which does is *usually* an
indication of a lack of understanding of reference types and parameter
passing.

See http://www.pobox.com/~skeet/csharp/parameters.html for more
information.

--
Jon Skeet - <(E-Mail Removed)>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too