Peter Gfader 's .net Blog

Strange behaviour with Local Accessfile as DB with relativ path

2008-07-11T15:48:00.003+02:00

If you are using an AccessFile as DB.
And specify it as relativ path in your app.config file like this


<add name="MSAccess" connectionString="Provider=Microsoft.Jet.OLEDB.4.0;
Data Source=..\..\AccessFile\LocalAccess.mdb;
User Id=admin;Password=;" providerName="System.Data.OleDb" />

If you are using OpenFileDialog or SaveFileDialog
you must ensure to set RestoreDirectory = true

If you are not doing so, your access-file will not be found after some FileDialog...

The default value is false.
RestoreDirectory = false on default


openFileDialog1.RestoreDirectory = true ;

Data driven unit tests with Filenames from a directory!

2008-07-08T10:02:00.003+02:00

Idea for simple data-driven-unit-tests:
Create 2 folders in your solution
/valid-test-files/
/invalid-test-files/

copy in those folders your single files to test.
execute unit test with these files...

but how???

there is no dataprovider (DataSource) for directories (not in vs2005, in vs2008 im not sure)

i did it this way.
create in each folder a text file.
/valid-test-files/data.txt
/invalid-test-files/data.txt

these text files will contain a directory listing with the single files!

add to your unit test


[DeploymentItem(@"invalid-test-files\data.txt", @"invalid")]
[DataSource("System.Data.OleDb", @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=.\invalid-test-files;Extended Properties='text;FMT=Delimited'", @"data.txt", DataAccessMethod.Sequential)]

now you will get in your unit test the single files

string fileName = TestContext.DataRow[0].ToString();

but how to fill the files data.txt?
use this method in Assembly Initialization


        [AssemblyInitialize]
        public static void CreateOutputDataTxtFiles(TestContext context)
        {
            
            string startDir = Path.Combine(Path.GetDirectoryName(Path.GetDirectoryName(context.TestDir)), @"Siag.XXX.BusinessLogic.Test");
            string addDir = @"valid-test-files";

            WriteFilePathsToData(Path.Combine(startDir, addDir), "*.dat");

            addDir = @"invalid-test-files";

            WriteFilePathsToData(Path.Combine(startDir, addDir), "*.dat");

        }


        private static void WriteFilePathsToData(string startDir, string searchPattern)
        {
            StringBuilder result = new StringBuilder();

            foreach (string fileName in Directory.GetFiles(startDir, searchPattern))
            {
                result.AppendLine(fileName);
            }

            // add additional directories here

            string fileNameData = Path.Combine(startDir, @"data.txt");

            File.SetAttributes(fileNameData, FileAttributes.Normal);
            File.WriteAllText(fileNameData, result.ToString());
        }

Create pdfs from within .net c#

2008-06-13T16:07:00.002+02:00

pdflib vs. reportviewer

advantages +
disadvantages -

pdflib
+ create pdfs with attachments
- mail merge (blocks) difficult to handle
(adobe plugin not working, ...)
- bad sourcecode (coding style of pdflib)
- operates on strings not with exceptions...

reportviewer
+ easy layout
+ export not only in pdf (html, csv, xls,...)
- no dedicated pdf creation (only export report)

TO validate:
iText.NET
iText.NET is a Free PDF Library for .NET Framework
ported from java

NEUINSTALLATION Visual Studio - Link Tip

2008-06-03T09:52:00.000+02:00

"Pimp My IDE": 101 Visual Studio tips, tricks, and add-ins

Exception: Operation must be an updatable query when you use an local Access File (.mdb)

2008-05-30T19:15:00.003+02:00

SOLUTION
The Access File .mdb is readyonly, from sourcecontrol

this problem is resolved by Helper: RemoveReadOnlyFlagAccessFile()

Code Snippet to remove ReadOnly


        public static string RemoveReadOnlyFlagAccessFile()
        {
            string returnValue = "";

            string connString = GetAccessConnectionString();
            if (string.IsNullOrEmpty(connString))
            {
                returnValue = "ConnectionString not found";
            }
            else
            {
                //FORMAT
                //connectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=..\..\AccessFile\oracle-reverse-engineered-modified-manually.mdb;User Id=admin;Password=;"
                if (connString.ToUpper().Contains("OLEDB") == false)
                {
                    returnValue = "ConnectionString is not for MsAccess. doesnt contain OLEDB. ConnString: " + connString;
                }
                else
                {
                    int indexStart = connString.IndexOf("Data Source=");
                    if (indexStart <= 0)
                    {
                        returnValue = "ConnectionString is not correct. doesnt contain Data Source=. ConnString: " + connString;
                    }
                    else
                    {

                        string tempString = connString.Substring(indexStart + 12);
                        int indexEnd = tempString.IndexOf(".mdb");
                        if (indexEnd <= 0)
                        {
                            returnValue = "ConnectionString is not correct. doesnt contain .mdb. TempConnString" + tempString;
                        }
                        else
                        {
                            string filePath = tempString.Substring(0, indexEnd + 4);
                            string fullPath = Path.GetFullPath(filePath);

                            if (File.Exists(fullPath) == false)
                            {
                                returnValue = "File doesnt exist: " + fullPath;
                            }
                            else
                            {
                                returnValue = "File " + fullPath + " is: " + File.GetAttributes(fullPath).ToString() + "\n";

                                try
                                {
                                    File.SetAttributes(fullPath, FileAttributes.Normal);
                                    returnValue += "File " + fullPath + " NOW is: " + File.GetAttributes(fullPath).ToString() + "\n";
                                }
                                catch (Exception ex)
                                {
                                    Logger.Write("EXCEPTION in File.SetAttributes:   " + ex.ToString());
                                    returnValue += "Exception on File.SetAttributes";
                                }
                                
                            }


                        }
                    }
                }
            }

            //Logger.Write("FileUtils.RemoveReadOnlyFlagAccessFile  returnValue: \n" + returnValue);
            return returnValue;

        }


        private static string GetAccessConnectionString()
        {
            

            if (System.Configuration.ConfigurationManager.ConnectionStrings.Count == 0)
            {
                throw new ApplicationException("Set ConnectionString in .config file!");
            }
            if (System.Configuration.ConfigurationManager.ConnectionStrings.Count == 1)
            {
                return System.Configuration.ConfigurationManager.ConnectionStrings[0].ConnectionString;
            }
            else
            {
                // try "MasterMSAccess", then empty, then firstone
                if (System.Configuration.ConfigurationManager.ConnectionStrings["MasterMSAccess"] != null)
                {
                    return System.Configuration.ConfigurationManager.ConnectionStrings["MasterMSAccess"].ConnectionString;
                }
                else if (System.Configuration.ConfigurationManager.ConnectionStrings[""] != null)
                {
                    return System.Configuration.ConfigurationManager.ConnectionStrings[""].ConnectionString;
                }
                else
                {
                    return System.Configuration.ConfigurationManager.ConnectionStrings[0].ConnectionString;
                }

            }
        }

Application.Exit vs. Environment.Exit

2008-05-30T10:27:00.000+02:00

Essence of the blog post!


if (System.Windows.Forms.Application.MessageLoop)
{
 // Use this since we are a WinForms app
 System.Windows.Forms.Application.Exit();
}
else
{
 // Use this since we are a console app
 System.Environment.Exit(1);
}

Application.Exit vs. Environment.Exit

TIP: The symbol file im.pdb does not match the module

2008-05-28T14:52:00.001+02:00

If you encounter
"The symbol file pdb does not match the module"

Try to look in
Debug -> Windows -> Modules
Ctrl-D, M

there you can see where vs2008 tries to load the .pdb file.

SOLUTION
Rebuild your dll in DebugMode and deploy it there!

The symbol file im.pdb does not match the module - MSDN Forums

Problems!! Unit testing with Visual Studio 2008

2008-05-27T10:24:00.003+02:00

#1
with this hack i solved some problems


        [ClassInitialize]
        public static void ClassInitialize(TestContext testContext)
        {
            AppDomain.CurrentDomain.SetData("APPBASE", Environment.CurrentDirectory);
            Console.WriteLine("DEBUG: " + AppDomain.CurrentDomain.BaseDirectory);
        }

BUT with our Base.dll i got an Exception dll not found!

SOLUTION
I must copy our Base.dll to c:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\

then it works!
not NICE

#2
to find all configured sections, usersettings, agents-dlls i need my app.config resp. my web.config but
the App.config works with VS2008 with VS2005 not.
SOLUTION
in VS2005 i must add the VSTestHost.exe.config then it works.

or maybe it works even with App.config

TO TEST!

#3
at last i get my solution always checked out when i run my unit test.
the vs2008 does add the vsmdi file as Solution Item.

how can i disable this?

A post that helped at first time.
But Next time it gets checked out.
http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=499083&SiteID=1

DataGridView daily problems...

2008-05-19T15:17:00.003+02:00

i have a DataGridview with some ComboBox cells in there.

each row should have a different list of items to select the value from.

you can set the bindingsource on Enter and reset the bindingsource to the list with all items on EndEdit...

in dataGridView CellEnter


if (e.ColumnIndex == CELLINDEXWhereComboBoxIs)
{
  //Set DataSource of cell if comboBoxCell
   DataGridViewComboBoxCell cell = (DataGridViewComboBoxCell)dataGridView[e.ColumnIndex, e.RowIndex];
   cell.DataSource = bindingSourceFiltered;
}

in dataGridView CellEndEdit


if (e.ColumnIndex == CELLINDEXWhereComboBoxIs)
{
   //set DataSource to BindingSource with all items
     DataGridViewComboBoxCell cell =   (DataGridViewComboBoxCell)dataGridView[e.ColumnIndex, e.RowIndex];
   cell.DataSource = bindingSourceAll;
}

ps:
you can add filters to the bindingsource!
but only if the underlying list supports filtering!!

Data driven unit tests with Text Files!!

2008-04-15T08:28:00.003+02:00

i wanted to do unit tests with a text file as input
1 line contains: entity serialized as string, entityName and other parameter

e.g.
1|12|123123,123123,143123|54| Riga1_GPS true

line is delimited by tab

#1
create file in your test project
righevalid.txt
File Properties: --> Copy to Output Directory --> copy always

#2
create file in your test project
schema.ini
File Properties: --> Copy to Output Directory --> copy always

#3
content of schema.ini

[righevalid.txt]
Format=TabDelimited

#4
create testmethod

#5
add following attributes to testmethod

        [TestMethod()]
        [DeploymentItem(@"righevalid.txt")]
        [DeploymentItem(@"schema.ini")]
        [DataSource("System.Data.OleDb", @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=.;Extended Properties='text;FMT=TabDelimited;HDR=YES'", @"righevalid.txt", DataAccessMethod.Sequential)]
        public void LoadValidRigaTest()
        {
        }

Note
DeploymentItem copies files to Test Run Directory

DataSource is a special OleDb Usage with txt Files

#6
use TestContext.DataRow[index] to access your single columns (line) of the text file
TestContext.DataRow[0] = col1 and so on

#7
Run Test

#8
see output Passed or Failed
Doubleclick Result you can see the result of the single lines!

GREAT!

TinyMce with webeditor Control IN ACTION

2008-02-13T14:08:00.004+01:00

Control hosted in Winforms Application:

Control in Editmode - new Form ShowDialog

Transactions with MSAccess mdb File

2008-02-08T14:23:00.000+01:00

If you use Distributed Transactions within your Application and an Access .mdb a DataContainer then you maybe did get this:


System.InvalidOperationException: The ITransactionLocal interface is not supported by the 'Microsoft.Jet.OLEDB.4.0' provider.  Local transactions are unavailable with the current provider.

SOLUTION:
Don't let Access participate in this Distributed Transaction
System.Transactions.TransactionScopeOption.Suppress

Msdn Link:
Supporting Transactions in OLE DB

Entreprise Library: Exception Handling Policies

2008-02-01T14:29:00.000+01:00

wir sind gerade bei der migration von Microsoft Oracle Client nach Oracle Data Provider.

WICHTIG in app.config
wenn man bei 2 exceptionTypes einfügt, greifen diese Regeln nicht!

weiss nicht wieso.
aber mit nur einer funzts.
wenn beide exceptionTypes drin sind, werden diese nicht abgehandlet.

KOMISCH


  <exceptionHandling>
    <exceptionPolicies>
      <add name="Global Policy">
        <exceptionTypes>
          <add type="System.Exception, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" postHandlingAction="NotifyRethrow" name="Exception" />
        </exceptionTypes>
      </add>
      <add name="DataAccess">
        <exceptionTypes>
          <add type="Oracle.DataAccess.Client.OracleException, Oracle.DataAccess, Version=1.102.3.0, Culture=neutral, PublicKeyToken=89b483f429c47342" postHandlingAction="ThrowNewException" name="OracleException">
            <exceptionHandlers>
              <add type="Siag.DataAccess.ExceptionHandler.OracleODPExceptionHandler, Siag.DataAccess" name="Custom Handler" />
            </exceptionHandlers>
          </add>
    
     <!-- <add type="System.Data.OracleClient.OracleException, System.Data.OracleClient, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" postHandlingAction="ThrowNewException" name="OracleException">
            <exceptionHandlers>
              <add type="Siag.DataAccess.ExceptionHandler.OracleExceptionHandler, Siag.DataAccess, Version=2.0.0.11969, Culture=neutral, PublicKeyToken=null" name="Custom Handler"/>
            </exceptionHandlers>
          </add>
          -->

        </exceptionTypes>
      </add>
    </exceptionPolicies>
  </exceptionHandling>

XmlSerializers problems...

2008-01-31T14:06:00.000+01:00

Last days i got a strange error.

Could not load file or assembly CodeGenerator.XmlSerializers Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.

CodeGenerator = my actual working project

even in fuslogvw.exe it seems to look for that strange assembly

-> Project Properties -> Build
-> Generate serialization assembly = ON
didnt work!

-> Debug
-> Exceptions
-> Reset ALL
WORKS!

details in:
FileNotFoundException while calling web service from web service - MSDN Forums - couldn't locate myProject.XmlSerializers

String.Intern() Method

2008-01-23T17:03:00.000+01:00

i knew that strings are immutable and that we should use Stringbuilder.

but the method String.Intern(inputString) i didnt know!

- the method looks up the intern string pool for inputString.
- if it founds it, it assigns the reference to thisone.
and it will be not created a new instance of the inputString.

consider memory consumption vs. performance !!!
we have more the performance problem than the memory consumption problem.

Link:
Bob On Development » Optimize Memory Consumption Using String Interning

odp.net 1. Schritte und Fazit

2008-01-22T10:20:00.000+01:00

#1
mit Enterprise Library 3 funzt odp.net nicht

wird nicht unterstützt
es fehlt di Oracle.DataAccess.Client.OracleClientFactory
ist erst in oracle client 11 drinnen

tried to install dll in GAC mit gacutil
but wrong version of Oracle.DataAccess.dll
when i open my .dll in reflector then i cant see a OracleClientFactory.
there is no Oracle.DataAccess.Client.OracleClientFactory in Oracle.DataAccess, Version=1.102.3.0, Culture=neutral, PublicKeyToken=89b483f429c47342

#2
Default Werte von Storeds werden nicht unterstützt
like:
PNUM_FROM_INDEX NUMBER := NULL,
PNUM_TO_INDEX NUMBER := NULL,

wenn Parameter weggelassen werden kommt
06550: line 1, column 7:\nPLS-00306: wrong number or types of arguments in call to

wenn Parameter dazu und .Value nicht gesetzt -> wert = null in db

auch mit oracle 10g dbms funzt nicht!

Solution
Param must be added to command, but it will not have db's default value in the next case:
PNUM_TO_INDEX NUMBER := 100,

#3
beim aufruf im DAO ist die gleiche reihenfolge der params wie in plsql-signatur einzuhalten

auch mit oracle 10g

#4
Parameter weglassen mit Oracle10g
Test auf oracle 10G funzt auch nicht
{"ORA-06550: line 1, column 7:\nPLS-00306: wrong number or types of arguments in call to 'SPC_RA_PG_TESTDATA'\nORA-06550: line 1, column 7:\nPL/SQL: Statement ignored"}

und wenn Parameter übergeben und .Value nicht setzen auch nicht!

#5
DateTime.MaxValue
Probleme mit Select, Insert OK
Fehler wenn dieses wieder geholt werden will (Select)

-----------------------------------------
was ändert sich?

in plsql
- kein TO_CLOB von xmltype
- XMLTYPE ist XMLTYPE und nicht CLOB
- reihenfolge der parameter

in DAO
getten von Out Parameter
// HACK: BEFORE: recordCount = Convert.ToInt64(countParam.Value);
recordCount = (long)((Oracle.DataAccess.Types.OracleDecimal)(countParam.Value)).Value;

Enterprise Library problem behoben mit:


using (Oracle.DataAccess.Client.OracleConnection conn = new Oracle.DataAccess.Client.OracleConnection(connectionString))
{
  command.Connection = conn;
  //Siag.DataAccess.Configuration.ConnectionProcessorConfigurationSection.Open(conn as System.Data.Common.DbConnection);
  conn.Open();

Lesen (SELECT) von BLOB CLOB und XMLTYPE
immer über Storeds


resultItem.SetLargedatablobWithoutStatusChange(reader.IsDBNull(indexLargedatablob) ? null : (byte[])reader.GetOracleBlob(indexLargedatablob).Value);
resultItem.SetLargedateclobWithoutStatusChange(reader.IsDBNull(indexLargedateclob) ? null : reader.GetOracleClob(indexLargedateclob).Value);
resultItem.SetXmlcontentWithoutStatusChange(reader.IsDBNull(indexXmlcontent) ? null : reader.GetOracleXmlType(indexXmlcontent).GetXmlDocument());

Schreiben


param = new Oracle.DataAccess.Client.OracleParameter("PXML_PGTD_XMLCONTENT", Oracle.DataAccess.Client.OracleDbType.XmlType);
if (toPersist.Xmlcontent != null)
{
  param.Value = toPersist.Xmlcontent.InnerXml;
}
command.Parameters.Add(param);

Mapping zwischen Oracle Datatype - .net Datatype - .net reader Get Method
http://download.oracle.com/docs/html/B10961_01/features.htm

Oracle Native Datatype
CLOB - Character data can store up to 4 gigabytes (4 GB).
BLOB - Unstructured binary data can store up to 4 gigabytes.

Generic Constraints thougths

2007-12-19T15:20:00.000+01:00

There are 3 types of constraints.

A derivation constraint indicates to the compiler that the generic type parameter derives from a base type such an interface or a particular base class.

class LinkedList where K : IComparable

A default constructor constraint indicates to the compiler that the generic type parameter exposes a default public constructor (a public constructor with no parameters).

class Node where T : new()

A reference/value type constraint constrains the generic type parameter to be a reference or a value type.

class MyClass where T : struct
class MyClass where T : class

xml namespaces Seltsamheiten (german post)

2007-12-19T11:33:00.000+01:00

Namespaces dienen der Eindeutigkeit von Elementen und Attributen.
Namespaces sind beliebige Strings
Namespaces bauen normalerweise auf URLs auf --> Eindeutigkeit

Namespace Präfix dient zur Abkürzung (des Unique Identifiers)

Deklaration von einem Namespace beinhaltet Nennung einer Namespace URI sowie der Vergabe eines Präfixes (=Stellvertreter)

Namespaces werden in Elementen deklariert
Namespaces werden auf Element und Unterelement angewandt
Unterelemente können jedoch Namespace überschreiben

<prefix:myElement xmlns:prefix="http://www.gfader.com>

Kombination aus Namespace und Name (Attribut oder Element) = Qualified Name

StandardNamespace

<myElement xmlns="http://www.gfader.com">

leerer Namespace = unqualified Elements or Attributes
Wird kein Namespace deklariert so gilt xmlns=""

unqualified da sie nur lokalen Name und keinen Namespace haben

Standard-Namespace sollte nicht verwendet werden da :

Element OHNE Präfix im Standard-Namespace
Attribut OHNE Präfix im leeren Namespace

Beispiel:

<prefix:myElement xmlns:prefix="gfader.com" myAttribute="value">

myElement in StandardNamespace "gfader.com"
myAttribute in leerem Namespace ""

Damit auch myAttribute im selben Namespace ist:

<prefix:myElement xmlns:prefix="gfader.com" prefix:myAttribute="value">

Zusammenfassung aus Uni Vorlesung von Clemens Kerer
und
dotnet Magazin Artikel von Martin Szugat
Ausgabe 1/2.08 dot.net magazin - Aus dem Nähkästchen

Microsoft.mshtml .dll problems... und the solution!!

2007-12-14T17:59:00.000+01:00

i developed a winforms application that shows and edits html data.
(for details see older posts)

the control that i use, uses the mshtml library from the Microsoft.mshtml.dll found in the Application Folder of vs2008

"c:\Program Files\Microsoft Visual Studio 9.0\Visual Studio Tools for Office\PIA\Office11\Microsoft.mshtml.dll"

but this dll is ARRGGGH!

following problems:

gacutil /u
uninstall doesnt work on my local machine

gacutil /i
install doesnt work on terminal server without vs2008

cause its delay signed, only public key!

i think that the assembly is installed by MSI Windows Installer
and this adds some info to the registry

http://support.microsoft.com/kb/873195/en-us

SOLUTION

1. Download: Primary Interop Assemblies for Office 2003 from msdn
2. then installed the PIA 2003 msi from the packed exe
3. used this dll
4. deploy this dll
everything is fine!

details
verification of the dlls

\Program Files\Microsoft Visual Studio 9.0\Visual Studio Tools for Office\PIA\Office12>sn -v Microsoft.mshtml.dll--> Microsoft.mshtml.dll is a delay-signed or test-signed assembly

dll from vs2008 PIA folder
sn -v Microsoft.mshtml.dll
Microsoft (R) .NET Framework Strong Name Utility Version 2.0.50727.42
Copyright (c) Microsoft Corporation. All rights reserved.
--> Assembly 'Microsoft.mshtml.dll' is valid

How to get javasrcipt returnValue from webbrowser control (tinymce htmlcode fron webbrowser)

2007-12-05T11:10:00.000+01:00

In my previous post about the htmlcontrol i have not explained how i communicate with the tinymce javascript to get the actual values from the textarea.

Here is it how it works...


string valueFromTinyMce;

IHTMLDocument2 htdoc2 = editor2.HTMLDocument2;
IHTMLWindow2 parentWindow = htdoc2.parentWindow;
if (parentWindow != null)
{
 IHTMLElement el = htdoc2.createElement("input");
 el.id = "myValue";
 ((IHTMLDOMNode)htdoc2.body).appendChild((IHTMLDOMNode)el);

 parentWindow.execScript("document.all['myValue'].value = tinyMCE.getContent('mce_editor_0')", "javascript");

 valueFromTinyMce = el.getAttribute("value", 0);
}

GREAT Windows Forms Html Control

2007-12-05T11:03:00.001+01:00

I finally found a working HTMLControl to show and Edit HTML Content for Windows Forms Applications.

It uses internally a webeditor Control, and works great.
I did not verify memory usage :-)

http://www.codeproject.com/cs/miscctrl/editor_in_windows_forms.asp

Maybe this link will work!
http://www.codeproject.com/KB/edit/editor_in_windows_forms.aspx

I have modified it to work with tinyMce.
Normally it is in NON Enabled Mode.
If it goes into Editmode (DesignModeEnabled=true) then it shows the tinymce

http://tinymce.moxiecode.com/

If someone is interested in my code let me know...

EDIT
i have made some screenshots.

And here i explain how you can communicate with the hosted webeditor, resp. tinymce

Unable to load DLL oramts.dll - Oracle DB with Transcations

2007-11-26T10:24:00.000+01:00

To use the Oracle Client with Transactions (TransactionScope)
you must install: Oracle Services For MTS

Client.Net_9207\Disk1
Start SETUP -> Oracle Services For MTS ...

MTS = Microsoft Transaction Server

Then you can use code like this with Oracle DBMS


using(System.Transactions.TransactionScope scope = new System.Transactions.TransactionScope())
{
    finally
   {
          if (conn != null)
          {
              conn.Close();
          }
   }
   scope.Complete();
}

Solution to: System.InvalidOperationException: There is already an open DataReader associated with this Command which must be closed first.

2007-11-21T10:42:00.000+01:00

from an internet website:
a datareader represents an open connection to the database.
to run 2 readers simultaneously, you need to use two seperate connections.

#1
just change your connection string to add it back (add MultipleActiveResultSets=True to connection string).http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=123691&SiteID=1
NO SOLUTION

#2
new Connection on every GetConnection() --> no singleton
NO SOLUTION
ERROR: Invalid attempt to MetaData when reader is closed.

#3
connectionstring always another!
NO SOLUTION
ERROR: Invalid attempt to MetaData when reader is closed.

#4
BackgroundWorker solves the problem!

Flagsattribute - How to remove a flag from flaglist

2007-11-20T11:34:00.000+01:00

Is in this documentation not so easy to find...

But it works with the Bitwise XOR Assignment Operator!

FontStyle fontStyle = this.textBox1.Font.Style;
fontStyle = FontStyle.Italic FontStyle.Bold;

fontStyle = fontStyle ^ FontStyle.Bold;
//Removes the flag Bold from the fontStyle flagAttributes list

http://msdn2.microsoft.com/de-de/library/system.flagsattribute(VS.80).aspx

Programmatically change Acceptbutton want work!

2007-10-26T13:33:00.001+02:00

If you try to change the Form.Acceptbutton of a form in the Click event of another button, that is currently the Acceptbutton then you must:

#1
//Select next control (simulates Tab press)
this.SelectNextControl(this, true, true, true, true);

#2
//Set new Acceptbutton
this.ParentForm.AcceptButton = buttonLogin;

when you press Enter 2times now it works!

UPDATEif SelectNextControl doesnt work use

this.SelectNextControl(buttonWhichIsActuallySelected, true, true, true, true);

then it should work!