Development

Generating Indexes for Foreign Keys

by jbrooks 18. September 2014 09:03

Surprisingly SQL Server doesn’t automatically create indexes just because you have a foreign key. So at the end of a development project I just used the script below to generate the SQL needed.

select 'create index indx_'+t.name +'_' + c.name + ' on ' + t.name +'(' + c.name + ');' from sys.foreign_key_columns as fk inner join sys.tables as t on fk.parent_object_id = t.object_id inner join sys.columns as c on fk.parent_object_id = c.object_id and fk.parent_column_id = c.column_id where not exists (select 1 from sys.index_columns ic where ic.object_id = t.object_id and ic.column_id = c.column_id) order by 1

This returns the commands that I can then run to create the indexes.

create index indx_ActivityLog_activityTypeId on ActivityLog(activityTypeId);
create index indx_ActivityLog_userId on ActivityLog(userId);
create index indx_Areas_managerId on Areas(managerId);
create index indx_Categories_areaId on Categories(areaId);
create index indx_CriteriaItems_criteriaColorId on CriteriaItems(criteriaColorId);

Tags:

SQL | Development

Silverlight Page Titles

by jbrooks 9. September 2013 17:21

In the past I would use part of the page for the page title while the MainPage had a lot of empty space in the center.  I wanted to move the title from the page to the MainPage as shown below.

image

 

To do this I first made a property on MainPage like this:

public partial class MainPage : UserControl
{
    public string Title
    {
        get { return tbTitle.Text; }
        set { tbTitle.Text = value; }
    }

Then I added this property to the App class:

public partial class App : Application
{
    public static string Title
    {
        set
        {
            MainPage mp = App.GetMainPage();
            mp.Title = value;
        }
    }

A supporting method in this same App class is GetMainPage() where it gets the MainPage. I use this for other things too.

public static MainPage GetMainPage()
{
    if (Application.Current.RootVisual.GetType().Name == "BusyIndicator")
        return (MainPage)((ChangeAlerts.Controls.BusyIndicator)
            Application.Current.RootVisual).Content;
    else
        return (MainPage)Application.Current.RootVisual;
}

Then on each individual page I have something like this:

protected override void OnNavigatedTo(NavigationEventArgs e)
{
    App.Title = "Manage Accounts";
}

Tags:

Silverlight | Development

Binding a Silverlight DataGrid’s ComboBox To a Model

by JBrooks 31. July 2013 11:49

I have a DataGrid that is bound to my Employee entity and I needed to be able to select his building from a list of buildings in that same model. There is a path to the Employee’s Building through buildingId, but no path to the full list of buildings so it could the source for the ComboBox.

The simple solution was to have the Buildings in a ViewModel and then reference that as a resource in my XAML.  The ViewModel retrieves the data in it’s constructor and it has a property EntitySet<Building> Buildings;

    <UserControl.Resources>
        <vm:BuildingsModel x:Key="buildingsModel"  />
    </UserControl.Resources>

Then on the CheckBox inside the <DataTemplate> I have its ItemSource use the resource.

<ComboBox Name="cb" ItemsSource="{Binding Source={StaticResource buildingsModel}, Path=Buildings}" 
    SelectedValuePath="id" 
    SelectedValue="{Binding Path=buildingId, Mode=TwoWay}">
    <ComboBox.ItemTemplate>
        <DataTemplate>
            <StackPanel Orientation="Horizontal">
                <TextBlock Text="{Binding name, Mode=OneWay}" MinWidth="140" />
                <TextBlock Text="  " />
                <TextBlock Text="{Binding address, Mode=OneWay}" />
                <TextBlock Text=", " />

                <TextBlock Text="{Binding city, Mode=OneWay}" />
                <TextBlock Text=", " />
                <TextBlock Text="{Binding state, Mode=OneWay}" />
            </StackPanel>
        </DataTemplate>
    </ComboBox.ItemTemplate>
</ComboBox>
 
 
 

Tags:

Development | Silverlight | XAML

Silverlight and Window Authentication

by JBrooks 4. June 2013 08:38

I deployed my Silverlight application with Windows Authentication.  I then set IIS to only use Windows Authentication. When I navigated to the web site I would get the error:

“Load operation failed for query ‘GetUser’. The remote server returned an error: NotFound.”

getusererror

The fix that worked for me was to edit the file MyProject.Web/Services/AuthenticationService.cs.  I just changed this one method.

public class AuthenticationService : AuthenticationBase<User> {

    protected override User GetAuthenticatedUser(System.Security.Principal.IPrincipal principal)
    {
        User newUser = new User();
        newUser.Name = principal.Identity.Name;

        return newUser;
    }
}

This makes sense if you think about it, but the base class AuthenticationBase should have detected the authentication used and changed based on that.

Tags:

Development | Silverlight

Show Child Count in a DataGrid

by jbrooks 11. March 2013 17:49

I have an application with the following as part of the data model:

image

So an Account can have many Users and a user can belong to many Accounts. I wanted to show the Accounts in a DataGrid along with the number of Users that were linked to that account like show in the 3rd column here:

image

The way I did this is to use a converter to count the number of entities in each Account.xrefAccountsUser set.  The DataGrid is bound to Accounts and the the XAML for the 3rd column is:

<sdk:DataGridTextColumn  Header="Users" 
Binding="{Binding xrefAccountsUsers, Converter={StaticResource setToCountConverter}}"
 />

The converter is where we count up the number of entities in the related entity set (xrefAccountsUsers in this case.)  I could not find a type that I could cast the value to that had a Count property, so I  ended up casting it to IEnumerable and then loop thru the set and I do a count manually.  There should never be very many accounts so performance isn’t an issue.

public class SetToCountConverter : IValueConverter
{
    public object Convert(object value,
                                Type targetType,
                                object parameter,
                                System.Globalization.CultureInfo culture)
    {
        int cnt = 0;
        IEnumerable set = value as IEnumerable;
 
        if (set == null)
            return "0";
 
        foreach (var item in set)
            cnt++;
 
        return cnt.ToString();
    }
 
    public object ConvertBack(object value,
                                Type targetType,
                                object parameter,
                                System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

Tags:

Silverlight | Development | XAML

Disable CheckBoxes in Silverlight’s DataGrid

by jbrooks 11. March 2013 12:41

I have an application where the administrator can edit a user’s roles.

image

I wanted to reuse this same grid to show the user what roles they have, but I didn’t want them to be able to change the data. There is a IsReadOnly property on each of the columns, but this still allows the user to change the checkboxes.

If I set the IsEnabled property on the datagrid to false, then the user can’t change the checkboxes but the datagrid looks washed out and hard to read.

image

So this is too washed out to go with.  I realized that another way to disable CheckBoxes is from the style:

<sdk:DataGrid.Resources>
    <Style TargetType="CheckBox">
        <Setter Property="IsThreeState" Value="False" />
        <Setter Property="HorizontalAlignment" Value="Center" />
        <Setter Property="VerticalAlignment" Value="Center" />
    </Style>
</sdk:DataGrid.Resources>

I wanted to see if there was a way to programmatically add a setter to this and there was.

// find the CheckBox style resource.
var resource = dgAccounts.Resources.FirstOrDefault(x => x.Key == typeof(CheckBox));
    
if (resource.Key != null)
{
    Style s = resource.Value as Style;
    
    (s.Setters as SetterBaseCollection).Add(new
    Setter(CheckBox.IsEnabledProperty, value));
}
    

In the code above, “value” can be true or false.  This gives me a little better presentation:

image

But, hey, this is Silverlight – why am I using those dinky check boxes anyway.  The better solution is to create a user control that acts like a checkbox and you can style it as big as you want.

image

And then the code to set the disable style just needs to change the type it is looking for on the 1 line:

var resource = dgAccounts.Resources.FirstOrDefault(x => x.Key == typeof(ucCheckBox));

Now, the disabled version is a lot more readable.

image

Tags:

Development | Silverlight | XAML

Silverlight's DatePicker / MessageBox Bug

by JBrooks 26. December 2012 10:49

Silverlight has an annoying bug that has been around since at least 2008. If you have a MessageBox popup in a DatePicker’s SelectedDateChanged event, then the calendar will stay open and the SelectedDateChanged will fire for each time the mouse pointer hovers over a new date.  See HERE for someone asking for help on this and their sample code.

It happens because the DatePicker still flags the left mouse button as being down – the up button event was eaten by the message box.

I have a page where the user works on data for a given day, and if they change the date the page will be refreshed with the new day’s data.

My work flow was that if a user changed data for a day and then changed the date, I would prompt them with “Save Changes?” – Yes, No, Cancel.  If they selected Cancel I would just set the DatePicker’s date back. 

No matter what they selected the DatePicker’s calendar would remain down and the SelectedDataChanged would fire for each date that was hovered over.

I didn’t like any of the answers to this problem that I found.  So I changed the workflow so that the prompt to save changes wasn’t necessary anymore.  So this is the new workflow.

1. New page, you can change the date, refresh the data, or start editing the data.

image

2. The data was changed. Now changing the date is disabled until you make a choice between Save and Cancel. I like how this visibly tells the user that the data is dirty.

image

This is done by capturing the KeyUp event for the parent control that holds all of the editing controls. In my example it is a ContentControl but it could be a grid, etc.  Note that the control’s in the images above are outside of my ContentControl for the data.

private void ccData_KeyUp(object sender, System.Windows.Input.KeyEventArgs e)
        {
            switch (e.Key)
            {
                case Key.Left:
                case Key.Right:
                case Key.Down:
                case Key.Up:
                case Key.Tab:
                    break;

                default:
                    if (Status != PageStatus.Changed)
                    {
                        Status = PageStatus.Changed;
                    }
                    break;
            }
        }

When the Status property gets set the showing, hiding and disabling of controls takes place depending on the new value of PageStatus.

If the user clicks “Save” then the data is saved, the page is refreshed and they are back at step 1 with the date selection enabled. If they click “Cancel”, then I go to step 3.

3. They clicked “Cancel”.  Now they are free to change the date which pulls up another day’s data and throws away their changes (step 1).   Or they can continue editing, which puts them back to step 2.  Or they can click Refresh which will pull the old data from the database and the page will be back to step 1.

image

I like doing it this way so I don’t have to mess with the SelectedDateChanged event and I like the visual cues.

Tags:

Development | Silverlight

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

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