Jim's blog | .Net and SQL Server blog

Generic Boolean to Text Converter

by JBrooks 20. July 2012 11:52
I’ve seen this done a few different ways, but I think this is the best way because you can reuse it. Below is the converter, notice the 2 public properties.
public class BoolToTextConverter : IValueConverter
{
    public string TrueText { get; set; }
    public string FalseText { get; set; }

    public object Convert(object value, Type targetType, object parameter, 
                                                   System.Globalization.CultureInfo culture)
    {
        return ((bool)value) ? TrueText : FalseText;
    }

    public object ConvertBack(object value, Type targetType, object parameter,
                                                  System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }

}
Then in your XAML resource section you would set the properties:
<localHelpers:BoolToTextConverter x:Key="boolToTextConverter">
    <localHelpers:BoolToTextConverter.TrueText>
        Sent
    </localHelpers:BoolToTextConverter.TrueText>
    <localHelpers:BoolToTextConverter.FalseText>
        Not Sent
    </localHelpers:BoolToTextConverter.FalseText>
</localHelpers:BoolToTextConverter>
So this is setting the 2 public properties. The final part is to bind this to the TextBox, in this example I’m binding to a boolean property named “sent”. The result is that the text will be “Sent” if it is true and “Not Sent” if it is false.
<TextBlock Text="{Binding Path=sent, Converter={StaticResource boolToTextConverter}}"
            VerticalAlignment="Center" Margin="4"  
            TextAlignment="Center" />

Tags:

Silverlight | Development | XAML

Smart Phone Development for .NET Developers

by JBrooks 18. February 2012 21:26

As a .NET developer I was feeling left out of the IPhone, Android and BlackBerry world, until now! 

Let’s start by looking at the sample application that I created in Visual Studio as learning exercise.  The application allows you to create a note at a GPS location.  I called it NoteToPlace and you can open it in your phone by going to www.NoteToPlace.com   You can register and start using it now.

Here is what the opening screen looks like on an IPhone:

Home

This is the basic look and feel out of the box given the tools I used (talked about below.)  You can install this as an app on the IPhone so the browser related stuff at the top goes away.  The user will also have an icon on their home screen just like every other app - so it isn’t obvious to them that this is really a browser based app.  And no you don’t have to go through the App store.  See this link for more details: HTML5 IPhone App.

Once the user clicks the “Create A Note” option from the main menu they get prompted to allow the application to know their GPS location, and then they get this page to add a note:

CreateNote

A few things to note.  First, notice the upper left hand corner shows me as logged in (as user “j”).  All of the ASP.Net membership stuff came free out of the box (or template.) That includes the pages for a user to register and to log in.

Also note that I used a different emulator for this second image – this is how it looks in a Motorola Droid X. I tried out the following emulators:

  1. http://iphonetester.com/
  2. http://dev.opera.com/articles/view/opera-mobile-emulator/
  3. http://ripple.tinyhippos.com/
  4. https://www.google.com/chrome/

(The images are in this order.) I mostly used the desktop version of Chrome for development and I use fiddler2 for debugging.  I just change the size to be close to a phone’s. All of these emulators were free.

In my sample app, if I go back and select the second main menu option “View My Notes”, I will get a list of my notes. Show below in the Ripple emulator:

Ripple

It is easy to create lists like these and you see them a lot. If I then click the “Map” link for an item I will see the Google map of the location where I left the note:

Map

 

Note that I didn’t spend any time optimize this application for performance (it is just a test of the technologies.)  It can take some time on the first load. HTML5 has an advanced application caching feature that I didn’t use at all, but looks promising for a real effort.  Also note that the Google map page has problems displaying in some situations (sometimes you just need to hit refresh.)

Developer’s Section

Now for the technologies used.  First, I downloaded and installed MVC4 beta from ASP.Net.  This installs Visual Studio templates that allow you to create a MVC 4 project and then select “Mobile Application” as an option.

Doing this will install JQuery Mobile into your project which is the part that does a lot of the user interface.  From there you are doing HTML 5 in the markup, EF4 for the data access layer (YEAH!) and MVC for the application. There was also more JavaScript / JQuery then I would have liked.

I didn’t know MVC before this application and learned it from these free videos: MVC from Pluralsight.  (I took heavy notes while I watched them.) You can build a mobile application using ASP.Net WebForms, but in my research it became clear that MVC with JQuery Mobile is the future here. You can add MVC to your currently existing WebForms application, see HERE.

Also, I found this book to be very helpful when I started:

 

It is a good overview of mobile development and is heavy on JQuery Mobile. They even have a chapter talking about PhoneGap where you can turn your application into a native IPhone or Android application.  PhoneGap is open source and more information can be found HERE.

The Google maps page was done with a JavaScript call to the Google maps API. More information can be found HERE.

I wouldn’t build a game using this technology, but it looks very promising for building web related apps. I think it will be valuable in extending some of the web applications that I currently work on. Now I have the option to include a little mobile where it makes sense and adds value.

Tags:

Development | HTML5 | MVC | Phone

One Click CheckBox in a Silverlight DataGrid

by JBrooks 16. December 2011 09:54

I found this code on the internet to create a CheckBox in a DataGrid that wouldn’t require more than one click to change.  But it didn’t work for me.

<sdk:DataGridTemplateColumn>
    <sdk:DataGridTemplateColumn.CellEditingTemplate>
        <DataTemplate>
            <CheckBox IsThreeState="False" IsChecked="{Binding Path=IsActive, Mode=TwoWay}" 
                      HorizontalAlignment="Center" VerticalAlignment="Center" />
        </DataTemplate>
    </sdk:DataGridTemplateColumn.CellEditingTemplate>
</sdk:DataGridTemplateColumn>
The reason it didn’t work is because I also had this as part of my DataGrid
<sdk:DataGrid CurrentCellChanged="dgTotals_CurrentCellChanged" …

 

That method had a dgTotals.BeginEdit(); in it to allow the user to begin editing the DataGrid cells without having to first click on them.  The simple solution was to just skip that for my CheckBox column.

if(dgTotals.CurrentColumn != null && dgTotals.CurrentColumn.DisplayIndex != 1)
    dgTotals.BeginEdit();

Tags:

Development | Silverlight

Troubleshooting the Silverlight to RIA Services Connection

by JBrooks 6. December 2011 11:41

The first thing I do when troubleshooting a Silverlight startup error (like where it just has the startup progress bar sitting at 100% forever) is to make sure I can reach the RIA Service and it doesn’t return an error.

This example shows how to decode the URL back to the service:

http://localhost:1893/MWEntry5-Web-Services-ScheduleDomainService.svc

This is just the path delimited with dashes to the service as seen in your project and also with all of the periods changed to dashes and then just add “.svc” at the end.

clip_image001

You should see a page for the RIA Service if you put this URL in a browser.

When calling a method it is ClientBin first, followed by the name space, followed by “binary” and then your method name.  Here are 2 examples:

http://localhost:1893/ClientBin/MWEntry5-Web-Services-ScheduleDomainService.svc/binary/GetSchedulableEntities

http://MyDomain/MyWebApp/ClientBin/MyWebApp-Web-AuthenticationService.svc/binary/GetUser

I just needed to put this somewhere so I can reference it in the future.

Tags:

Silverlight | Development

.NET and Silverlight Rounding

by jbrooks 10. November 2011 09:09
In Excel 34.5 will round to 35 and in .NET it will round to 34. This is because .NET defaults to using the MidpointRounding.ToEven mode – also called banker’s rounding.  In .NET you have the option of overriding this by passing in the other MidpointRounding like:
 
    Math.Round(34.5, MidpointRounding.AwayFromZero);   // Now rounds to 35

A little annoying since in all of the applications that I’ve ever written the users expect rounding to match Excel’s and I’ve never needed the default. Worse, in Silverlight you don’t even have the option to change the default when using Math.Round().

So I had to write my own extension that can be used like:

 
    double myValue = 34.5;
    
    int myRoundedValue = (int) myValue.RoundCorrect(0);  // rounds to 35
 

Here is the extension code:

public static class DoubleExtensions
{
    public static double RoundCorrect(this double d, int decimals)
    {
        double multiplier = Math.Pow(10, decimals);
 
        if (d < 0)
            multiplier *= -1;
                                   
        return Math.Floor((d * multiplier) + 0.5) / multiplier;
    }
}

or if you want the code for a normal method it would be

public double RoundCorrect(double d, int decimals)
{
    double multiplier = Math.Pow(10, decimals);
 
    if (d < 0)
        multiplier *= -1;
 
    return Math.Floor((d * multiplier) + 0.5) / multiplier;
 
}

Tags:

Development | Silverlight

Changing the RIA Services Connection String for Different Environments.

by jbrooks 9. November 2011 07:24

On one project we keep our connection string as an AppSetting (See: HERE).  So that is what I use to build my RIA Services connection string to account for the differences between Dev, Test, QA and Prod.  You could also do the same with a regularly stored connection sting.  Here is how we did it:

public partial class MyDomainService
   {

       protected override MyEntities CreateObjectContext()
       {
           string ConnString = Common.cApp.AppSettings["DefaultConnection"];

           string seConn = ConfigurationManager.ConnectionStrings["MyEntities"].ToString();

           EntityConnectionStringBuilder ecsb = new EntityConnectionStringBuilder(seConn);
           ecsb.ProviderConnectionString = ConnString;

           EntityConnection ec = new EntityConnection(ecsb.ToString());

           ScheduleEntities ctx = new ScheduleEntities(ec);

           return ctx;

       }

   }

Tags:

Silverlight

MSBuild with Silverlight / RIA Services

by jbrooks 2. November 2011 09:36

I introduced a Silverlight project to my ASP.Net application and every thing worked fine in development but when I went to build it with out automatic build process MSBuild would kick out the following error:

[msbuild]   App.xaml.cs(2,17): error CS0234: The type or namespace name 'Services' does not exist in the namespace 'MyProject.Web' (are you missing an assembly reference?)

Had to change a registration key, the DefaultToolsVersion was set to 2.0, changed  it to 4.0

image

 

Ran the install selecting repair for the Silverlight 5.0 sdk (silverlight5_sdk.exe) – it was originally installed as part of the tool kit, but found others saying the real install still needed to be done to get it to work with MSBuild.

Next go the error:  error MSB4044: The "CreateRiaClientFilesTask" task was not given a value for the required parameter "ClientFrameworkPath"

Had to install EntityFramWork4.1 on my build server and then reboot.

Now on to the next problem.

Tags:

Silverlight | Development

Generating Passwords

by jbrooks 19. August 2011 07:46

We have the requirement that our passwords have to change every 90 days.  I wanted to automate this and it sounded pretty easy to do, but it wasn’t that easy.  Why? Because there are a lot of rules for passwords.

First, I have to store it in the web.config.  So no XML special characters.

  1. quot "
  2. amp &
  3. apos '
  4. lt <
  5. gt >

Next, If used in an OLE DB or ODBC connection string, a password must not contain the following characters: [] {}() , ; ? * ! @.

Finally, strong passwords must contains characters from at least three of the following categories:

  1. English uppercase characters (A through Z)
  2. English lowercase characters (a through z)
  3. Base 10 digits (0 through 9) 
  4. Nonalphabetic characters (for example: !, $, #, %)

So keeping all of these rules in mind I created a simple class. that I can just call

public class PasswordGenerator
{
    private static string CHARS_LCASE = "abcdefgijkmnopqrstwxyz";
    private static string CHARS_UCASE = "ABCDEFGHJKLMNPQRSTWXYZ";
    private static string CHARS_NUMERIC = "23456789";
    private static string CHARS_SPECIAL = "*-+_%/";
    private static string CHARS_ALL = CHARS_LCASE + CHARS_UCASE + CHARS_NUMERIC + CHARS_SPECIAL;
 
    public static string GeneratePassword(int length)
    {
        char[] chars = new char[length];
        Random rand = new Random();
 
        for (int i = 0; i < length; i++)
        {
            switch (i)
            {
                case 0:
                    chars[i] = CHARS_LCASE[rand.Next(0, CHARS_LCASE.Length)];
                    break;
                case 1:
                    chars[i] = CHARS_UCASE[rand.Next(0, CHARS_UCASE.Length)];
                    break;
                case 2:
                    chars[i] = CHARS_NUMERIC[rand.Next(0, CHARS_NUMERIC.Length)];
                    break;
                case 3:
                    chars[i] = CHARS_SPECIAL[rand.Next(0, CHARS_SPECIAL.Length)];
                    break;
 
                default:
                    chars[i] = CHARS_ALL[rand.Next(0, CHARS_ALL.Length)];
                    break;
            }
        }
 
        return new string(chars);
    }
}

So now I just simply call this for a new password:

PasswordGenerator.GeneratePassword(13)

Tags:

Binding a Silverlight DataGrid’s ComboBox

by JBrooks 6. May 2011 07:13

Some things in Silverlight seem harder than they should be.  Binding a list of strings to a combobox is one such thing.  This involves the following steps to do a simple bind.

1. Have a private list of the strings in your page code.

 
private List<string> FuelList = new List<string>()
         {
             "OIL",
             "GAS",
             "COAL"
         };
 

2. In your initialization method add the list as a resource so your XAML can use it.  This must be done before the InitializeComponent(); call.

 
        public ucMyUserControl()
        {
            this.Resources.Add("FuelList", FuelList);
 
            InitializeComponent();
        }

 

3. Then you can reference the list as the source to you combo box.

<sdk:DataGrid AutoGenerateColumns="False"  MinHeight="130" Name="dgMyDataGrid" 
    ItemsSource="{Binding Path=ScheduleRows, Mode=TwoWay}"  
        CurrentCellChanged="dgMyDataGrid_CurrentCellChanged">
 
 
  <sdk:DataGrid.Columns>
     <sdk:DataGridTemplateColumn  Header="Fuel Type">
         <sdk:DataGridTemplateColumn.CellTemplate>
             <DataTemplate>
                  <TextBlock Margin="2" VerticalAlignment="Center"  
            HorizontalAlignment="Left" Text="{Binding FUEL_TYPE}" Width="120" />
             </DataTemplate>
             </sdk:DataGridTemplateColumn.CellTemplate>
                  <sdk:DataGridTemplateColumn.CellEditingTemplate>
                     <DataTemplate>
                         <ComboBox Height="23" Name="cbxFuelType" 
                                 ItemsSource="{StaticResource FuelList}"
                                 SelectedValue="{Binding Path=FUEL_TYPE, Mode=TwoWay}" Width="120">
 
                         </ComboBox>
                      </DataTemplate>
             </sdk:DataGridTemplateColumn.CellEditingTemplate>
        </sdk:DataGridTemplateColumn>
...

4. One last item, notice the datagrid’s current cell changed event is wired up to start editing without requiring the user to click first.  That method is simple enough:

private void dgMyDataGrid_CurrentCellChanged(object sender, EventArgs e)
  {
      dgMyDataGrid.BeginEdit();
  }

 

 

That gives me my datagrid with my combo box:

image

 

 

Here is a sample solution that has the full code: 

 ComboBoxTest.zip (1,016.17 kb)

Tags:

Development | Silverlight

Silverlight TextBox Watermark

by JBrooks 8. April 2011 07:45

The Silverlight TextBox does have a Watermark property, but Microsoft says “Do not use in a Silverlight 4 application” HERE.    So I looked into making one myself and it didn’t take much to do it. 

I just wanted the text box below to show the text “Search” in a grayed out way.

image

To do this it is just setting the forground color.

<TextBox Name="tbxSearch" Width="120" Text="Search" Foreground="#5A000000" 
    VerticalAlignment="Center" GotFocus="tbxSearch_GotFocus" />

 

I also wanted to reset the text to the normal color and to clear the text box when the user gave it focus.  Simple enough. If you notice above, the GotFocus event is wired up to the following method:

private void tbxSearch_GotFocus(object sender, RoutedEventArgs e)
{
    if (((SolidColorBrush)tbxSearch.Foreground).Color != Colors.Black)
    {
        tbxSearch.Text = "";
        ((SolidColorBrush)tbxSearch.Foreground).Color = Colors.Black;
    }
}

So that is it except that this should be made into a user control.

Tags:

Silverlight

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