---- Reported by juergen@cis-comsoft.de 2004-11-01 07:48:15 MST ----

Description of Problem:

XSD creates strongly typed DataSets that throw exceptions when accessing
the column-properties of datarows.

Steps to reproduce the problem:
step 1.
Create Database on PostgreSQL
Use this as input for psql:

CREATE DATABASE test;

\c test

CREATE TABLE "simple" (
    nr smallint,
    name character varying(10)
);

COPY "simple" (nr, name) FROM stdin;
1	Peter
2	Paul
3	Mary
\.

--### end of psql-input

step 2.
//Create test_ds.xsd

using System;
using System.Data;
using System.Data.Common;
using Npgsql;

class MainClass
{
    public static void Main(string[] args)
    {
        string connStr="Server=localhost;User ID=juergen;Database=test";

        NpgsqlConnection conn = new Npgsql.NpgsqlConnection(connStr);
        conn.Open();
        DataSet ds = new DataSet("testDataSet");
        NpgsqlDataAdapter da = new NpgsqlDataAdapter("SELECT * FROM simple
WHERE 1=0;", conn);
        Console.WriteLine(da.Fill(ds, "simple"));
        ds.WriteXmlSchema("test_ds.xsd");
        conn.Close();
    }
}

####### 
output is test_ds.xsd:

<?xml version="1.0" standalone="yes"?>
<xs:schema xmlns:msdata="urn:schemas-microsoft-com:xml-msdata"
id="testDataSet" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="testDataSet" msdata:IsDataSet="true" msdata:Locale="de-DE">
    <xs:complexType>
      <xs:choice maxOccurs="unbounded">
        <xs:element name="simple">
          <xs:complexType>
            <xs:sequence>
              <xs:element minOccurs="0" name="nr" type="xs:short" />
              <xs:element minOccurs="0" name="name" type="xs:string" />
            </xs:sequence>
          </xs:complexType>
        </xs:element>
      </xs:choice>
    </xs:complexType>
  </xs:element>
</xs:schema>

step 3. 
Create source for test_ds.c

xsd test_ds.xsd /dataset

step 4.
Use test_ds:

using System;
using System.Data;
using Npgsql;

class MainClass
{
    public static void Main(string[] args)
    {
        string connStr="Server=localhost;User ID=juergen;Database=test";

        NpgsqlConnection conn;
        Schemas.testDataSet tds = new Schemas.testDataSet();

        conn = new NpgsqlConnection(connStr);
        NpgsqlDataAdapter da = new NpgsqlDataAdapter("SELECT * FROM
simple;", (NpgsqlConnection)conn);
        
        Console.WriteLine(da.Fill(tds.simple));

        Console.WriteLine(tds.simple[0].name);
        Console.WriteLine(tds.simple[0].nr);
        
        conn.Close();
    }
}

Actual Results:
Exceptions accessing tds.simple[0].name and tds.simple[0].nr

Expected Results:
No exceptions ;-)

How often does this happen? 
every time

Additional Information:
There are 2 places in the get-accessor of the column properties of datarows
that throw exceptions. Look at comments

public virtual short nr {
    get {
        // next line (XSD-created) throws NullReferenceException because
        // InitializeFields for the table is never called and so the
        // column-variables aren't set. Calling it after InitializeClass
        // in the table-constructor makes this work (don't know if that's
        // the right place to call it...).
        object ret = this[this.table.nrColumn];
        if ((ret == System.DBNull.Value)) {
            throw new System.Data.StrongTypingException("Cannot get strong
typed value since it is DB null.", null);
        }
        else {
            // next line (XSD-created) throws InvalidCastException
            // the equivalent for strings seems to work
            return ((short)(ret));

            // this works
            return Convert.ToInt16(ret);
        }
    }
    set {
        this[this.table.nrColumn] = value;
    }
}



---- Additional Comments From atsushi@ximian.com 2004-11-02 09:40:02 MST ----

I haven't tried pgsql-dependent code, but that typed column problem
should be fixed (both in HEAD and 1.0-branch). If other problems still
happens, please reopen or create another bug report. Thanks.



Unknown bug field "cf_op_sys_details" encountered while moving bug
   <cf_op_sys_details>Ubuntu 4.10</cf_op_sys_details>