To leverage the DatePicker control just drag it on the form. Then in the form load function determine the format (e.g., DateTimePicker1.Format = DateTimePickerFormat.Short ). The selected date is then available in the Text property of the control (and should show up on the form). By default today's date should be shown.

The key properties for the calendar are

SelectionStart - This is the first selected date (it is possible to select multiple dates at a time!)

TodayDate - This sets today's date (which otherwise is set automatically by the system clock!)

Enumerations are commonly used for small sets of finite values (i.e., types or status). It is easy to work with Enums in the .NET framework, the .NET compact framework, however, has some limitations. The example below is for an Enum called PersonStatus (with the values Here, There, Somewhere)

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        ' In the .NET framework this would work
        '    Me.ComboBox1.DataSource = [Enum].GetNames(GetType(PersonStatus))
        ' Unfortunately this does not work in the .NET Compact Framework
        ' So some hardcoding needs to be done ...
        Me.ComboBox1.Items.Add("Here")
        Me.ComboBox1.Items.Add("There")
        Me.ComboBox1.Items.Add("Somewhere")
    End Sub

    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        Select Case Me.ComboBox1.SelectedItem
            Case "Here"
                thisPerson.Status = PersonStatus.Here
            Case "There"
                thisPerson.Status = PersonStatus.There
            Case "Somewhere"
                thisPerson.Status = PersonStatus.Somewhere
            Case Else
                'do nothing
        End Select
    End Sub

Powered by Zoundry

        Dim al As New ArrayList()
        Dim da As DataItem()
        Dim di As DataItem

        Try
            'test item (your item may have other attributes!)
            di = New DataItem
            di.ID = "0000" 'provide unique ids
            di.Name = "test"
            di.Value = 1.0
            al.Add(di)

            'another item
            di = New DataItem
            di.ID = "0001"
            di.Name = "test again"
            di.Value = 1.0
            al.Add(di)

            '... and so on

            da = al.ToArray(GetType(DataItem))

            Return DataManagementSystem.saveDataItems(da)
        Catch ex As Exception
            Return ex.Message
        End Try

I have created - for everyone who has sent me a class and a Web service URL - a web service that can be leveraged by the mobile device application for the project.

Some examples are

John's pricing service

Tom's Restaurant service

All the services provide basic CRUD functionality for each class ... create, read, update, delete ... and are based on my DataManagementService. John, for example, has three classes, thus he has quite a few more functions in his service than Tom. Depending on their business logic not all of the methods may be used.

It is important to note that every class has an ID property with which an object can be identified.

Creating all the "different" Web services, was quite easy. In Tom's case I just had to find "DataItem" in my code and replace it with "Restaurant" ...

If you want to see the code behind this take a look at the DataManagementService project in the code folder on the G-drive.

The data.xml files are stored at ../fpdb/data.xml . That means in the fpdb folder right below your personal folder on the Web server, as this folder has the needed write permissions. In case you do want to view your data.xml you need to setup a "network location" to your fpdb folder (in my case http://www.746.sba.uwm.edu/mhaines/fpdb) (see FAQ for instructions).

MH

Note: The generateDataFile method is used to create a data file if none exist. However, I did create one already for each Web service. If the generateDataFile method is used all existing data will be lost!

Technorati : BUS ADM 740, Web service

Powered by Zoundry

For anyone you needs to do some direct XML processing (i.e., RSS feeds) take a look at the following past blog entry and other resources:

Blog post about Google Calendar feed

Slides with XML processing code

... or just use this RSS Feed Web service :-) (Just plug-in the RSS URL, it returns an RssFeed object with its "news" items. The application key is "rss".)

MH

Technorati : BUS ADM 740, RSS, XML

Vista users: In case you are getting stuck again with getting your device emulator to connect to the Internet after cradling it: Don't miss the last step in the Mobile Device Center!

In the Mobile Device Center, you should see the green check mark and "connected". However, that is not enough. Make sure you click on "connect with out setting up your device". Only after this step you can connect to the network (and the Internet). Check it out by running Internet Explorer in the device emulator.

If you can pull up a Web page you are good to go!

MH

Technorati : BUS ADM 740, device emulator

Just a note about creating your own Web service.

For a description on how to create a Web site project for a Web service see my previous blog entry regarding this issue.

I would like everyone to go ahead and create a Web site for your Web service. Once you have created it let me know by sending me the URL. This will allow me to check whether it has been created correctly.

The other thing that you probably want to send me is the classes that you will use in your project. This serves two purposes; one, I will be able to give you feedback on the class structure itself, second, I will be able to help you setup the functions in your Web service with the classes (i.e., getXList, updateX, ... whatever your X is).

One additional note. If you do want to test your Web service you need to insert this snippet of XML in your Web.config file:

      <webServices>
        <protocols>
          <add name="HttpPost"/>
        </protocols>
      </webServices>

It goes right under the

<system.web>

As you may have noted, lab #4 and assignment #4 are very similar. In fact, if you have completed the optional part of lab #4, you have essentially solved assignment #4.

Here is where the solution to assignment #4 may differ slightly from the lab. In the lab the patient information is loaded into the listboxes right upon loading the form. In your assignment you should have a load and a save menu option. The data can be loaded from the Web service or from the local file. This means you may provide two load menu options (load local and load remote) ... or you could write code that tries to always load the remote file via the Web service and when this is not possible tries the local file. The quick and dirty solution would be a a try-catch statement. Just let the remote attempt fail and load the local file in the catch part. The smarter solution is to determine with some code whether the device is connected .

In any case you will need to think about where the code that loads the data from the Web service has to go now, as this may be different from lab#4. There could be also some opportunity (not required) for refactoring!

A note regarding using XML. As it became apparent in the demo provided in the last class session, you may need to add the System.Xml reference to your project references. Go to MyProject, the Reference tab, and view the existing references. If it is not listed, click on Add Reference and select System.Xml from the list in the dialog box. Then add a Imports System.Xml.Serialization statement at the top of your code file.

MH

Technorati : BUS ADM 740, Web services, XML

Powered by Zoundry

How can one leverage XML without knowing much about XML?

The answer, as indicated in the previous posting, is XML serialization.

An XML serializer can be used to turn the data stored in objects into XML (and back from XML into objects). All the serializer needs to know is the class the objects are derived from. The serializer looks at the class definition and creates a corresponding XML structure. (The class has to be "serializable" and there are some cases where this automatic process will not work!)

Below is some example code in which an XML serializer is leveraged to save and load DataItem objects. The loadDataItems function reads the XML from a file and returns an array of DataItem objects. (DataItem could be replaced with Person, Patient, Contract, Restaurant, ... whatever your class is!). The saveDataItems function takes an array of DataItem objects and writes it to an XML file.

MH

--- Code ---

'need these imports at the top of your VB code!

   Imports System.Xml

   Imports System.Xml.Serialization

   Imports System.IO


   ...


   Public Shared Function loadDataItems() As DataItem()

   Dim mySerializer As XmlSerializer

   Dim dataItems As DataItem()


   Try

   mySerializer = New XmlSerializer(GetType(DataItem()))


   ' To read the file, create a FileStream.

   Dim myFileStream As FileStream = _

   New FileStream(_filePath, FileMode.Open)


   ' Call the Deserialize method and cast to the object type.

   dataItems = CType(mySerializer.Deserialize(myFileStream), DataItem())

   Return dataItems

   Catch ex As Exception

   Return Nothing

   End Try


   End Function


   Public Shared Function saveDataItems(ByVal dataItems As DataItem()) As Boolean

   Dim mySerializer As XmlSerializer


   Try

   mySerializer = New XmlSerializer(GetType(DataItem()))


   ' To write to a file, create a StreamWriter object.

   Dim myWriter As StreamWriter = _

   New StreamWriter(_filePath)


   mySerializer.Serialize(myWriter, dataItems)

   myWriter.Close()

   Return True

   Catch ex As Exception

   Return False

   End Try


   End Function

I had a chance today to review the project requirements documents and plans.

There are some very interesting projects, some even with potential for becoming something more than just a class project.

I encourage everyone to share their ideas, designs, and other insights related to the project on the blog. (Tag these entries with the keyword "project" so others can search for it!) It may give others some good ideas, but can also help to shape your own thinking.

Here are some of the key things that most need to focus on right now:

• Understand the data: identify the key entities, their characteristics, and relationships
• Define the actions: identify and describe the actions that uses may take, in "business" not in technical terms ("the user updates the database" is too technical, "updates the task status to completed" is more appropriate).

The conceptual data design will enventually result in a set of classes for your application. The great thing is that having these classes it is quite easy to save data stored in objects of this class in XML files ... without knowing much about XML. The process is called serialization and .NET provides a XmlSerializer class that makes this process quite simple.

More later ...

MH

Here is an example of how to use my NOAA Weather service. The service is available (and can be tested) at http://www.531.sba.uwm.edu/mhaines/webservices/NOAAWeatherService.asmx

For this example I created a simple form with a textbox called txtSearch, a button called btnFindLocations, a combo box called cbxLocations, and a label called lblWeather.

The user can enter a search term in the txt box and the weather stations that match will be added to the list of items in the combo box. The display member of the combo box is set to "description", thus the content of the description shows for each item.

There are two event handler routine shown in the example code below. One for the user clicking on the button, the other for the user selecting an item from the list. If you create controls (textboxes etc.) on your form with the same ID as I mentioned above, all you need to do is to insert the code in the class that represents your form, and create a Web reference to the weather Web service (see URL above) called wrefWeatherService .

    Private Sub btnFindLocations_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnFindLocations.Click
        Dim ws As New wrefWeatherService.NOAAWeatherService 'weather service objet
        Dim locations As wrefWeatherService.WeatherStation() 'array of weather stations called locations
        
        Try
            'get the locations matching search term from Web service
            locations = ws.searchLocation(txtSearch.Text)


            'fill the combo box
            cbxLocations.DisplayMember = "Description" 'show station description
            For Each thisLocation As wrefWeatherService.WeatherStation In locations
                cbxLocations.Items.Add(thisLocation) 'add station to list
            Next

        Catch ex As Exception
            lblWeather.Text = "ERROR - btnFindLocations_Click" & ControlChars.CrLf & ex.Message
        End Try

    End Sub

    Private Sub cbxLocations_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cbxLocations.SelectedIndexChanged
        Dim ws As New wrefWeatherService.NOAAWeatherService
        Dim weatherInfo As wrefWeatherService.WeatherInfo
        Dim l As wrefWeatherService.WeatherStation

        Try
            l = cbxLocations.SelectedItem
            weatherInfo = ws.getWeatherForLocation(l.StationName, l.StationRegion, l.StationCode, l.Longitude, l.Latitude)
            lblWeather.Text = weatherInfo.LocationName & ControlChars.CrLf
            lblWeather.Text += weatherInfo.TemperatureAirInFahrenheit & "F "
            lblWeather.Text += weatherInfo.TemperatureAirInCelsius & "C "
        Catch ex As Exception
            lblWeather.Text = "ERROR - cbxLocations" & ControlChars.CrLf & ex.Message
        End Try
    End Sub

  

The key steps for using a Web service are ...

1. Create a Web reference (need URL to WSDL of service)
2. Declare and create a Web service object (must create with New!)
3. A variable that can receive the result of the Web service needs to be declared (simple data type of complex type defined in Web service).
4. Call method of the Web service and receive the result
5. Do something with the result (i.e., but the weather stations in the listbox)

Technorati : BUS ADM 740, Web service

I have posted an example of a requirements document and project plan from last year's class.

Also take a look at the project milestone description on the course Web site.

MH

Technorati : BUS ADM740

Ok, now you have a Web service (or you know where there is one that provides the needed functionality), how do you leverage it.

Here are the key steps:

1. Know the URL of the WSDL for the Web service.
   The WSDL may reside on your local machine or on the Web. In case of the typical .NET Web service the WSDL can be accessed by adding a ?wsdl after the .asmx file of the Web service (i.e., http://www.531.sba.uwm.edu/mhaines/WebServices/testService.asmx?wsdl). If it is your Web service, an easy way to figure out the URL of the Web service is to run it in the browser and copy the URL from the browser.
2. Create a Web reference.
   Right-click on your project in Visual Studio and choose 'Add Web Reference'. In the dialog window provide the URL to the WSDL (or just the .asmx file, if it is a .NET based Web service) and hit 'Go'. If the Web service and its methods show up, provide a name for the Web reference. I like to call them wref... (i.e., wrefTestService for my testService.asmx) rather than the default reverse domain name.
3. Create a Web service object.
   Declare a variable of type WebReferenceName.ServiceName (i.e., Dim ws As New wrefTestService.TestService). The ServiceName is the name of the Web service class in the .asmx file! ... and don't forget to actually create the object with the keyword New (one of the top 10 mistakes)!
4. Use the Web methods of the Web service.
   Example: result = ws.testMethod()
   Keep in mind that the data type of result must match the data type returned by the service. A service method may also have input parameters.

You may also peek into the lab instructions for lab #1 of the BUS ADM 746 course.

BTW, here is a list of a couple of Web services that you can check out:

• test web service: http://www.531.sba.uwm.edu/mhaines/webservices/testService.asmx
• weather service: http://www.531.sba.uwm.edu/mhaines/webservices/NOAAWeatherService.asmx
• traffic service: http://www.531old.sba.uwm.edu/webservices/trafficservice.asmx/getTrafficInfo
• simple Amazon book list service: http://www.531.sba.uwm.edu/mhaines/webservices/amazon.asmx

Also look on the following sites for service:

• www.xmethods.net
• www.strikeiron.com
• www.serviceobjects.com

You also just search for it. If you are interested in a Web service that provides stock quotes just search for "stock quote Web service".

[Note: A - not all services listed always work , B - you may need to sign up for a trial license to use a service ]

MH

Technorati : BUS ADM 740, Web services

Powered by Zoundry

All students have a folder on our Web server available in which you can create Web services (and Web pages). The base URL is http://www.746.sba.uwm.edu/ . Just add your login name to the URL and that is your personal folder on the Web server under which you can create the Web sites.

It is fairly easy to get started with setting up a Web service. The step below outline the process of setting up a Web service.

1. Add a new Web site: right-click on your solution, then choose Add -> New Web Site.
2. Select the Web site type: In the dialog window choose ASP.NET Web service, make sure Visual Basic is selected as the language (unless you want to do this in C#!), the location is set to HTTP and the URL for your web site (your folder URL + name of Web site, for example: http://www.746.sba.uwm.edu/mhaines/myWebServices).
3. Provide your SBA login (e.g., SBA\mhaines)
4. TaDaa ... there is your Web service! By default a Service.asmx (and Service.vb) is created and a HelloWorld test method. You can leverage this default service or - I would recommend - just add another Web service to the project and name it according to what it does (i.e., TrafficService.asmx).
5. Create your Web methods. Leverage the HelloWorld function as a template to create your own. Note that a Web method must have the <WebMethod()>_ annotation above the function header!
6. Test the Web service by right-clicking on the .asmx file and selecting run in Browser. A test page should show up and you should see your Web methods. I will place some more detailed information in the FAQ.

Again, this is something you can check, if you want to learn about creating a Web service. It's not required.

One important thing that everyone will have to figure out, however, are the data structures that you many need.

So if you deal with customer information, you need to figure out what the data elements are that pertain to the customer. In the end you will need to create a class that represents these data elements. This may look like the example below:

    Class Customer
      Public ID As String
      Public FirstName As String
      Public LastName As String
      Public Email As String
    End Class

With this you can now write functions that for instance get a list of Customer objects. For example:

'this function gets an array of Customer objects (the customer list)
Function getCustomerList() As Customer()
  'code here 
End Function

If it is a Web Service function (Web Method) then add the Web Method annotation to the function header

'this function is a Web Method that gets an array of Customer objects (the customer list)
<Web Method()> _
Function getCustomerList() As Customer()
  'code here 
End Function  

OK, you have a Web service ... now what?

See next posting on consuming a Web service from an application, including a mobile smart device application.

MH

Technorati : BUS ADM740, Web service

Powered by Zoundry

Here are a few things that may be helpful in thinking about the project and arriving at conceptual design.

Most students have project scenarios that involve getting information from a "back-end" source to the mobile device.

Thus it is necessary to have to things:

1. some kind of back-end - even if it is just a simulated back-end, and
2. a mechanism to get the information from that back end to the mobile device.

A relatively easy answer to implement this is "Web services". Even if you are not accessing a real back-end, you can use them to simulate a back-end ... and that is sufficient for the proof-of-concept you will develop in this class!

If you are adventurous and would like to set up a simple Web service yourself, you can do this on your own (more below), if you just want to focus on your mobile application, I can setup a simple Web service for you with 2-3 basic operations (i.e., getCustomerList, saveCustomerList). I will follow-up with another post setting up a Web service.

I have already a number of services setup, including a weather service, a traffic service, a membership service (to manage users), a lottery number service, and a MCTS bus schedule service. (Some of these service require an application key, so talk to me if you want to use them!)

MH

Technorati : BUS ADM 740, Web services

Powered by Zoundry

I finally got around to check out how to connect the Smart Device Emulator in Vista. (See the course FAQ for doing this in XP.)

The big difference is that ActiveSync is replaced with the Windows Mobile Device Center.

It turned out to be pretty straightforward in my environment and fairly similar to setting up ActiveSync in XP. I tried this on my laptop running Vista Ultimate and Visual Studio 2008 (not 2005!). Before starting the device emulator I went to the mobile device center and opened up the connection settings. The only thing I had to adjust is the "allow connections to the following" (see image).

The "allow connection to the following" option has to be checked and DMA (direct memory access) needs to be selected. Then I started up the emulator via the device emulator manager in Visual Studio (Tools->Device Emulator Manager).

I cradled the emulator and ... it connected without a hitch.

Now, if you use Visual Studio 2005, you need to download and install the new device emulator (version 2). Visit the following sites for more information.

http://blogs.msdn.com/anandba/...

http://blogs.infosupport.com/blogs/willemm/...

Let me know if you still run into issues.

MH

Technorati : BUS ADM 740, device emulator, vista

So why did the "FirstName" did not show up in the listbox? It became already clear during the demonstration that it had nothing to do with the listbox, since the combo box also did not produce the intended results either.

As I figured out shortly after the class ended, the problem was not related to the code in the event handler routine nor the form frmStart in my smartDemoApp at all. The problem lies with the Person class declaration. Since we have not covered object-oriented programming and the concept of a class, my intention was to keep the design of the class as simple as possible, thus taking a shortcut.

All the class attributes , including "FirstName", were declared as simple Public attributes (as shown below).

Public Class Person
    Public FirstName As String
    Public LastName As String
    Public SSN As String
End Class

They should really have been declared as Public Properties instead. Usually it is considered good class design to make all attributes of a class private and use the property mechanism to expose them externally. As it is evident in the complete class declaration below, this makes the whole class declaration quite a bit longer and more complex.

Public Class Person
    Private _firstName As String
    Private _lastName As String
    Private _ssn As String

    Public Property FirstName() As String
        Get
            Return _firstName
        End Get
        Set(ByVal value As String)
            _firstName = value
        End Set
    End Property

    Public Property LastName() As String
        Get
            Return _lastName
        End Get
        Set(ByVal value As String)
            _lastName = value
        End Set
    End Property

    Public Property SSN() As String
        Get
            Return _ssn
        End Get
        Set(ByVal value As String)
            _ssn = value
        End Set
    End Property

End Class

So why did I think that my shortcut (not using properties) would work in the first place?
This relates back to Web services ... which is also beyond what we have covered so far in class.

A simplified Person class without using properties would have worked, if used in the context of a Web service. It comes down to the fact that Web services are not distributed objects, and the distinction between a property and a public attribute disappears, when a class is exposed via a Web service ... everything becomes a property.

I guess I have been doing a few too many Web service projects lately ;-)

So my lessons out of this failed demonstration are:

1) Only properties will be recognized as a display or value member

2) Web services are not distributed objects (and the distinction between an attribute and a property disappears)

3) Don't take shortcuts ... I need to read the story of the turtle and the hare again!

MH

P.S.,

You can download the code relating to the this demo from the G-drive (see course folder -> code -> smartDemoApp.zip)

Technorati : BUS ADM 740

Powered by Zoundry