28 Articles about ASP.NET

Performance, page templates, collapse datagrid, tricks of trace, caching (incl expiration callbacks), xslt in web forms, trace listeners, localization (i18n), graphics

Derive ASP.NET Pages from Common Base Class Provides consistent look/feel and avoids same code in many pages.
(Visual Studio Magazine)

Follow-up article, answers to questions.

(Visual Studio Magazine)

Sample DB Code

I always seem to be searching for samples of code to quickly query a db...so here they are, straight out of my toolbox clipboard !!

OLEDB DataSet

    OleDbConnection        db = new OleDbConnection( 

            @"Provider=Microsoft.Jet.OLEDB.4.0;

            Data Source=E:\databases\bulkdb.mdb;

            Persist Security Info=False" );

    OleDbDataAdapter    adapter = new OleDbDataAdapter();

    DataSet                ds = new DataSet();

    adapter.SelectCommand = new OleDbCommand( 

            "select * from tps_login", db );



    adapter.Fill( ds );

OLEDB DataReader

    OleDbConnection conn = new OleDbConnection( 

            @"Provider=Microsoft.Jet.OLEDB.4.0;

            Data Source=F:\databases\bulkdb.mdb;

            Persist Security Info=False" );

    OleDbCommand    cmd = new OleDbCommand(

            "select * from TPS_HINVENTORY", conn);

    conn.Open();

    OleDbDataReader r = cmd.ExecuteReader(

            CommandBehavior.CloseConnection);



    while ( r.Read() )

    {

        String      s = r.GetString(0);

        DateTime    dt = r.GetDateTime(3);

        Decimal     val = r.GetDecimal(4);

    }

Note with the DataReader, passing CommandBehavior.CloseConnection will cause the connection to be closed whenever the user of the returned object is done with it.

Simple DropDown List

I am such a newbie to the controls in .NET that I thought I'd write down a few thoughts on the differences between WebForms and WinForms version of a drop-down list.

WinForms ComboBox class.

	adapter.Fill( ds );		// fill some datasource

	cbNames.DataSource = ds.Tables[0];

	cbNames.DisplayMember = "T1USERNAME";

	cbNames.ValueMember = "T1LOGINID";

Then to get the data out when a selection is made..

	DataRowView drv = (DataRowView)cbNames.SelectedItem;

	MessageBox.Show( drv["T1LOGINID"].ToString() );

When storing items in the WinForms combobox, you add objects instead of strings like old school. A visual representation of the object is displayed in the combobox at runtime. The content representation is specified by DisplayMember - this value will be used as the "property" to retrieve from the stored object. If this property is not set, ToString will be used.

Use SelectedItem to retrieve the object representing the current collection. Cast it back to whatever you know it to be, then get at the data you want.

WebForms DropDownList class
DropDownList is the server control for the <option> HTML element. This works somewhat simliar to the ComboBox WinForms control but has a few notable differences.

	adapter.Fill( ds );

	list1.DataSource = ds.Tables[0];

	list1.DataTextField = "T1NAME";

	list1.DataValueField = "T1NID";

	list1.DataBind();

Then pull out the data with...

	lblText.Text = "You selected ID " + list1.SelectedItem.Value + 

                                     ", text is " + list1.SelectedItem.Text;

Since the control mimcs the OPTION element, it really only handles TEXT and VALUE pairs, so you use the DataTextField and DataValueField accordingly.

Then when you pull out the data for the selected item, it's just those two properties available on the System.Web.UI.Controls.ListItem class.

IDE Tricks

A few more tricks to remember -- from article at DevX "20 cool Visual Studio .NET IDE Features"

• <ctrl>+R, <ctrl>+R to toggle word wrap setting on the fly
  
• Paste from the clipboard ring (skipping over last copy) with SHIFT+CTRL+V
  
• Incremental search -- <ctrl>+I then start typing. F3 or <ctrl>+I to find next. F3 or <ctrl>+I one more time to get out of search mode.
  
• "Go Back" to previous editing spots with <ctrl>+ - (ctrl+hypen)
  
• Box selection with shift+ctrl+<drag mouse>
  
• Syntax coloring is preserved on print somehow (where's the setting?)