[Mono-list] Npgsql error

[Francisco Figueiredo Jr.]

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Fabian Salamanca Dominguez wrote:
> 
> Hi
> 

Hi Fabian!

> I tried to compile a simple C# program and access a Postgresql DB but I
> got this error in runtime (it compiled with no errors) :
> 
> [fsalaman at ipdserver Mono]$ mcs dbaccess.cs  -r:Npgsql.dll -r:System.Data.dll
> [fsalaman at ipdserver Mono]$ mono dbaccess.exe
> 
> Unhandled Exception: System.InvalidCastException: Cannot cast from
> source type to destination type.
> in <0x000e1> dbAccess:Main (System.String[] args)


>        string sql =
>            "SELECT operatingsystem, nodeid " +
>            "FROM assets";


What are the sql types of operatingsystem and nodeid?
Npgsql doesn't do any implicit conversion of types.

>        dbcmd.CommandText = sql;
>        IDataReader reader = dbcmd.ExecuteReader();
>        while(reader.Read()) {
>             string operatingsystem = (string) reader["operatingsystem"];
>             string nodeid = (string) reader["nodeid"];
>             Console.WriteLine("OS: " +
>                  operatingsystem + " " + nodeid);
>        }


To be sure, do the following:

Console.WriteLine(reader["operatingsystem"].GetType());

This will show you what type is being returned.

I hope it helps.



- --
Regards,

Francisco Figueiredo Jr.
Npgsql Lead Developer
http://gborg.postgresql.org/project/npgsql
MonoBrasil Project Founder Member
http://monobrasil.softwarelivre.org


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"Science without religion is lame;
religion without science is blind."

                  ~ Albert Einstein
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