Thom Robbins: General .NET Tips and Tricks

Want to try it out?

Sun, 15 Aug 2004 02:09:17 GMT

Is anybody besides me becoming an RSS junkie? Actually, that was a loaded question as it seems to be affecting many people. As part of the upcoming Mobility Day I’ve been putting together a variety of different samples to show. I started doing a simple feed reader to show some concepts of the Compact Framework, ADO and XML usage. It quickly became much more and finally evolved into a quite useful application. When I combined this application with my recent OS upgrade and the T-Mobile all you can eat data plan for my Pocket PC Phone, I was completely hooked. Both I and several others have been testing it over the last week and have given very positive feedback. I wanted to open it up to others and hope that they will use it and provide some feedback. What do you like? What do you hate? What do you want?

I designed the interface to take advantage of several different areas of the Compact Framework. I definitely ran into some of the short comings of the Compact Framework. The good news is that these are being added in 2.0. The most important problem was rendering HTML within my application. Well no worries, the folks at OpenNETCF solved that problem. Definitely, have some great stuff!

I wanted to do a quick introduction to News Reader an RSS reader written entirely using the Compact Framework 1.0.

Here is the startup screen

Here is the Read screen

Here is the message screen

Here is a short list of some of the features that I wanted to highlight

Maintains the last download date for feeds.
Maintains a local XML file with your posts.
Allows the deletion of individual messages or an entire feed.
Automatic retrieval of feed information based on an RSS URL.
Multiple feed retrieval based on selection
Able to consume both RSS 1.0 and RSS 2.0 feeds.
Maintains the local feed list using OPML

Please feel free to download the following files and let me know your feedback, bugs or comments that you may have.

Here are the links for download:

Pocket PC/Pocket PC Phone (Complete package)

Other CAB Files (CABs only)

OpenNETCF CABS (CABs only)

Installation instructions:

Extract the device specific zip files into a directory on your local machine.
You will need two CAB files. One is for the News Reader application. The second is for the OpenNETCF controls.
Copy these two files to your device.
Tap the two CAB files. This will install the application and remove the local copies of the CAB files.

Dataset,DataRow and other things

Sun, 08 Aug 2004 03:00:34 GMT

Question: I am trying to understand the dataset and how I can use it. It looks like a really powerful feature but it has an incredible amount of objects. It seems to me that I should be able to do simple things like create and edit values. But for the life of me I can’t seem to figure out how it works. Do you have some simple example that show how you can create a dataset and then update the individual rows?

Answer: Sure – here are some examples.

The following creates a dataset that we can use in the later examples.

' create the item table

Dim tblitem As DataTable = New DataTable("item")

Dim itemid As DataColumn = New DataColumn("itemno", _ Type.GetType("System.Int32"))

Dim colititle As DataColumn = New DataColumn("title", _ Type.GetType("System.String"))

Dim colipubdate As DataColumn = New DataColumn("pubdate", _ Type.GetType("System.String"))

Dim colidesc As DataColumn = New DataColumn("description", _ Type.GetType("System.String"))

Dim colilink As DataColumn = New DataColumn("link", _ Type.GetType("System.String"))

‘ create the columns

tblitem.Columns.Add(itemid)

tblitem.Columns.Add(colititle)

tblitem.Columns.Add(colipubdate)

tblitem.Columns.Add(colidesc)

tblitem.Columns.Add(colilink)

‘ add it to the dataset

ds.Tables.Add(tblitem)

Create a datatable from the dataset and insert a datarow.

Dim dt As DataTable = ds.Tables("item")

' get the datarow

Dim dtrow As DataRow

dtrow = dt.NewRow()

dtrow("itemno") = 10

dtrow("link") = "http://www.msn.com"

dt.Rows.Add(dtrow)

Select the new row and edit the value

Dim dr As DataRow() = dt.Select("itemno=10")

If dr.Length > 0 Then

dr(0).Item("link") = "http://www.test.com"

End If

dt.AcceptChanges()

Code Camp II: The Return!

Thu, 22 Jul 2004 15:20:34 GMT

*********CALL FOR SPEAKERS*********

Developer Code Camp II: The Return!

October 16/17, 2004

October 16 – 8:30 AM – 9PM

October 17 – 8:30 AM – 4PM

Microsoft Waltham

Schedule: http://radio.weblogs.com/0131777/CodeCamp2/code2.htm

General Call for Speakers

Code Camp II is looking for speakers and session leaders.

Code Camp II: The Return is looking to be even bigger and better than anything we have done before. The secret is you! This is a New England developer community based event that requires both speakers and attendees. The continuing goal of the Code Camps series is to provide an intensive developer to developer learning experience that is fun and technically stimulating. The primary focus is on delivering programming information and sample code that can be used immediately. The event is free and all slides, manuals and demo code are provided free!

This two day camp is hosted in our Waltham facility. As a community based event this is a general call for speakers and session leaders to help make this event a success. Based on your feedback, Code Camp II will now feature two types of 1.5 hour sessions and three defined tracks

Do you have something to say?

Requested Session Types:

Code focused presentation – These are presentations that include both power points and code demos. Given the audience that is attending it is important that a large amount of the presentation is focused on code and coding related techniques. Sample topics include How To and Best Practice Sessions.

Chalk Talks – These are new to the Code Camp. These sessions are designed as a facilitated discussion around a specific topic. No pre-canned demos, or pre-prepared code samples allowed! They are presented as a free form facilitated discussion that leverages the expertise of the presenter and the combined knowledge of the group to explore a specific topic.

Additionally, based on feedback we are sponsoring the following three tracks. All presentations must fall into these tracks to be considered. One of the strongest pieces of feedback from the last Code Camp was to provide a better organized set of tracks:

Code Camp Tracks:

Smart Client – This track is designed for presentations or chalk talks on topics related to Smart Client related development topics. This includes Windows Forms applications, Microsoft Office or mobile devices.

Web Track – This track is designed for presentations or chalk talks about Web based development that includes ASP.NET and Web Services.

Data Track – This track is designed for presentation and chalk talks about data storage technologies that includes SQL Server and XML.

********Submit Your Sessions********

Please complete the following and return it to trobbins@microsoft.com by September 15.

Once your session abstract is received we will review and provide scheduling for the selected sessions by October 1. All slides and code samples for the presentation must be delivered by October 14. If we are unable to fill all the time slots for the two days, the code camp will be shortened. It is the community that makes this event a success!

Name:
Company:
Email:
Phone:
Session Type:	Chalk Talk/Presentation (Select one)
Track:	Web/Smart Client/Data (Select one)
Level	200/300/400
Session Name:
Session Description:

Playing With Beta 1

Mon, 12 Jul 2004 00:38:25 GMT

Finally, got a chance to build an image using Visual Studio 2005 Beta 1. While writing some code I ran across something that I hadn’t seen in any of the documentation that I have read so far. I would typically use the following line to add a parameter to the SQL Command object.

sqlCmd = New SqlCommand

With sqlCmd

.Connection = sqlConn

.CommandTimeout = 30

.CommandType = CommandType.StoredProcedure

.CommandText = "spInsertFeedback"

.Parameters.Add("@EvaluatorName", EvaluatorName)

End With

According to the Intellisense that popped up, the Parameters.Add functionality has been made obsolete and now becomes.

sqlCmd = New SqlCommand

With sqlCmd

.Connection = sqlConn

.CommandTimeout = 30

.CommandType = Data.CommandType.StoredProcedure

.CommandText = "sp_GetCompanyName"

.Parameters.AddWithValue("@CustomerID", CustomerID)

End With

Accessing the Structure with XML

Wed, 07 Jul 2004 22:42:50 GMT

For this who read the .NET Developers Journal they have just published an article that I co-wrote this article with Raheel Retiwalla on SQL Server 2005 and ADO 2.0.

Or you can pick it up at the local newstands.

Accessing the Structure with XML

We were listening to a CIO explain how two years ago his company had instituted a mandatory XML policy for the IT staff. Senior management had decided that XML offered too great a competitive advantage for them to pass up using it. The use of XML, he explained, allowed them to quickly change and share their core business structures. The development staff had easily found ways to use XML within their applications.

Building Custom Controls with ASP.NET

Tue, 06 Jul 2004 14:40:29 GMT

For those attending my presentation tonight on Building Custom Controls with ASP.NET at our office in Waltham, I wanted to upload the slides and code samples for those interested. They can be found here.

What is Indigo?

Thu, 01 Jul 2004 23:06:28 GMT

I think we all have been trying to get a better handle on things like Indigo and some of the next generation technologies. If you are interested in this here is a great short video from the folks at Channel 9.

http://channel9.msdn.com/ShowPost.aspx?PostID=9792

For those that haven't checked out Channel 9 - a definate place to see!

A Quick Observation

Wed, 30 Jun 2004 03:10:14 GMT

Had a chance to talk with a customer today that was moving their current application to .NET. During the course of the conversation we talked through some of the features and types within the framework. One thing that they didn’t understand was that in VB 6 Date, is really a double type in disguise. Within the Framework DateTime is actually a value defined within the Framework. For examples, you can instantiate and initialize a DateTime class using the following example:

Dim TestDate As New DateTime(2004, 1, 31)

MsgBox(TestDate)

Which returns the date 1/31/2004

What is XML? And Why Should I Care?

Tue, 22 Jun 2004 15:30:43 GMT

As promised I wanted to post the information from my talk last night at the VB Learn User Group:

What is XML? And why should I care?

You've heard the hype but have you heard the facts? XML is clearly one of the most important standards within the technology industry. In this presentation Microsoft's Thom Robbins covers the structure and design of XML and how it should be used by developers. This presentation also covers the various companion technologies and standards that have been developed with XML (XSD and XSLT). These are important technologies for developers to understand not only for their own application development but as a cornerstone of the .NET Framework. Thom explains how these can be tied together and used within the .NET Framework for application development.

The samples and slides are available for download from here

Quick Directory Search

Tue, 22 Jun 2004 03:10:16 GMT

I got to spend the other day with a local customer that was making the shift to .NET. They were in the process of doing some prototyping their current application. They actually had a small VB application that was responsible for searching a local file share and returning a list of files that matched the search and their sizes. I put together the following snippet that I thought was interesting.

Imports System.IO

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim File

Dim Files() As fileinfo

Dim DirInfo As New DirectoryInfo("c:\")

Files = DirInfo.GetFiles("*.txt")

' display names

For Each File In Files

MsgBox("Name: " & File.Name)

MsgBox("Size: " & File.length.ToString)

End Sub

**Note**

The GetFiles operator accepts either the “?” or “*” search wildcards.

ADO.NET Best Practices

Sat, 05 Jun 2004 20:31:47 GMT

I really love talking to the local New England User Groups. I always have a great time and always manage to learn a few things myself. I think the information sharing at these groups really make it a worthwhile time investment. As I promised here are the slides and code samples for my talk on ADO.NET Best Practices.

Code Camp Samples

Mon, 31 May 2004 16:54:32 GMT

I had a chance to post what have been the most requested samples from the code camp. As you can guess they are from Patrick Hynds who is without a doubt one of the keys to the successful code camp!

Salt Demo
Custom Authorization
Forms Authentication

SQL Reporting Services Introduction

Fri, 28 May 2004 01:34:35 GMT

If you haven’t had a chance to check out SQL Reporting Services, I would highly recommend it. The product is actually pretty amazing. I had the opportunity today to present an overview of for some customers and as promised, I have posted the slides here for download. Also, for your reading pleasure, is the PDF format of my recent article that appeared in the .NET Developers Journal (INETA choice edition) download.

Defining Interfaces

Tue, 11 May 2004 15:40:56 GMT

Interfaces help to define the various properties, methods and events that classes are able to implement. For developers these fine a small group of closely related properties, methods, and events. Additional feature and functionality can be added at any by adding additional interfaces and implementations. Prior to .NET Visual Basic was able to consume interfaces but not able to create them directly. With Visual Basic.NET the INTERFACE statement was introduced. This statement allows the definition of a true interface as a distinct entity from classes and to implement them using the IMPLEMENTS keyword. The following is a simple example of creating a CustomerManagement interface.

Public Class Customer

Interface CustomerManagement

Function AddCustomer(ByVal CustomerName As String, ByVal CustomerAddress As String, ByVal CustomerContact As String)

Function DeleteCustomer(ByVal CustomerName As String)

Function UpdateCustomer(ByVal CustomerName As String, ByVal CustomerAddress As String, ByVal CustomerContact As String)

End Interface

End Class

This interface is implemented by using the IMPLEMENTS keyword as shown below.

Once implemented the defined interface contains all the functions defined within the interface. Like a class, interfaces define a set of properties, methods and events. However, unlike classes, interfaces provide no direct implementation. They are implemented by classes defined as a separate entity from classes. Metaphorically, an interface represents a contract. Within this contract a class that implements an interface agrees to implements every aspect of that interface exactly as it is defined.

It is important to remember that interface implementations are allowed to evolve. However, the interfaces themselves shouldn’t be changed once they are published. Changes to the interface may break existing code that has implemented the interface. Once again, like a contract both parties in the contract agree never to change that implemented interface.

Reflection and Optional Parameters

Wed, 05 May 2004 22:48:42 GMT

I received an email about my previous post about optional parameters. The email asked about how you could do this through reflection. Actually pretty easy using the GetType and InvokeMember and you should be all set. The Type.Missing does the trick for passing the optional value. One thing to keep in mind is that if there is no default parameter specified within the function this will cause an exception.

Here is a short example:

Code in the form

Imports System

Imports System.Reflection

Public Class Form1

Inherits System.Windows.Forms.Form

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim o As New InvokeMe

Dim t As Type

t = GetType(InvokeMe)

' Will throw an error because there is no default value

't.InvokeMember("PassOptParam", BindingFlags.Public Or BindingFlags.Instance Or BindingFlags.InvokeMethod Or BindingFlags.OptionalParamBinding, Nothing, o, New Object() {Type.Missing, Type.Missing})

t.InvokeMember("PassOptParam", BindingFlags.Public Or BindingFlags.Instance Or BindingFlags.InvokeMethod Or BindingFlags.OptionalParamBinding, Nothing, o, New Object() {10, Type.Missing})

End Sub

Code in the class

Public Class InvokeMe

Public Function PassOptParam(ByVal Number1 As Integer, Optional ByVal Number2 As Integer = 5) As Integer

MsgBox(Number2) ' returns 5

End Function

End Class

The Optional Keyword

Wed, 05 May 2004 21:20:27 GMT

I received an email from somebody today asking about the optional keyword. By definition, keyword is used to indicate that a procedure or argument can be omitted when a procedure is called. Here is a simple example of how you could use it.

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

PassOptParam(1)

End Sub

Private Function PassOptParam(ByVal Number1 As Integer, Optional ByVal Number2 As Integer = 5) As Integer

MsgBox(Number2) ' returns 5

End Function

Using Virtual PC for Application Testing

Tue, 04 May 2004 16:23:49 GMT

As promised here is a link to the slides from todays Virtual PC presentation by Rich -

This online Webinar covers how to use Virtual PC 2004 in a test environment, specifically for use in testing a given application against multiple Operating System configurations. We will show how to use Virtual PC to pre-configure multiple test systems, each of which is ultimately used to test an application under development. In this webinar, we will demonstrate:

- How to build and configure multiple test systems

- How to re-set a test environment back to an original configuration (for when things go wrong)

- How to create multiple Virtual Systems from a standard configuration / known base install

- Configuration and management of a test environment

download

Using XSLT - An Example

Sun, 02 May 2004 23:32:16 GMT

Using XSLT – An Example

I really like how I can use an XML document to separate the storage of application data from its presentation. The XML document contains a self describing set of data structures that I can define using my own vocabulary definitions. One of the major advantages of these documents is how easy they can be moved across the various process boundaries that exist within enterprises. This isolation of data into an XML allows a host processing the document to make the presentation decisions. An XML document by its very definition contains no formatting or presentation requirements. This is where the Extensible Stylesheet Language Transformation (XSLT) plays a major role. In this article I will show an example of how you can use XSLT to transform an XML InfoPath document in a Word 2003 document. More..

Creating and Moving Controls Dynamically within .NET

Sat, 24 Apr 2004 23:08:50 GMT

Question: I understand that .NET offers inheritance and I think that that may help with a project that I am currently working on. Let’s say that I have a single control. I want to use that control across multiple tabs on a form. How would I go about that?

Want to see my answer: Click Here

Back To Basics Content

Fri, 23 Apr 2004 17:04:08 GMT

The Back to Basics seminars that occurred in Waltham and Farmington this week seemed to be a bit hit. We had a combined total of about 280 developers that attended these events. For those that attended or those that are interested I have posted the decks and sample code.

.NET Developer Impact 1 (Slides)

.NET Developer Impact 2 (Slides)

.NET Developer Impact (Demo)

Base Class Libraries 1 (Slides)

Base Class Libraries 2 (Slides)

Base Class Libraries (Demo)

Developer Best Practices

Developer best Practices 1

Developer Best Practices 2

Visual Studio Tools for Office 2003

Wed, 21 Apr 2004 22:55:50 GMT

I had the opportunity to speak to the VB Learn User Group the other night. The focus of the presentation was on Visual Studio Tools for Office 2003. If you aren’t yet familiar with these tools, a definite must check out. They offer developers the ability to write managed code for Word and Excel within Office 2003. I have posted the slides and sample code from the presentation.

New Sample - Converting datasets and the InfoPath Receiver

Tue, 13 Apr 2004 23:27:23 GMT

I have been asked a couple of times about receiving data and datasets using InfoPath. In response I have posted what I hope is good example of how this can be done.

Let me know what you think!

SSL Test Certificate

Mon, 29 Mar 2004 23:05:21 GMT

Many times while working with customers, I end up needing an SSL certificate for testing on a web server. This ranges from typical web sites to SharePoint sites. Of course, actually getting the certificate isn’t always easy. I ran across this today and thought it would come in pretty handy. Thawte, the self proclaimed second largest certificate authority is offering a 21 day free downloadable SSL trial certificate.

http://www.thawte.com/ucgi/gothawte.cgi?a=w44700158187049000

XPath and .NET

Thu, 25 Mar 2004 14:13:36 GMT

Interested in getting the basics of XPath and .NET? Check out the latest article.

http://radio.weblogs.com/0131777/stories/2004/03/25/xpathAndnet.html

Smart Client Deployment

Thu, 25 Mar 2004 00:41:39 GMT

You can download the slides from my Live Meeting today on

Smart Client Deployment

This session will cover the issues and capabilities of Smart Client applications. The Smart Client is an application that runs outside of the browser taking advantage of the Windows Operating System. The biggest challenge to these applications has been their deployment and maintenance across thousands of clients. The .NET Smart Client directly addresses these issues while still taking advantage of the Internet protocols that power the distributed environments of today.

Slides are available here