topic Re: Collection View Source in ArcGIS API for Silverlight Questions

Collection View Source

MeConfused — Fri, 04 Feb 2011 19:31:20 GMT

I am trying to Sort the results from a buffer using Collection View Source...I think I am on the right path here but cant seem to get the sort to perform or refresh the listbox.
In this case I am trying to sort by the Buffer Distance being created fro each selected feature found inside the buffer
Note: BUFFER_DISTANCE is not a field in the feature...its being created or set below in blue

Any quick thoughts?

    Private Sub QueryTask_ExecuteCompletedBuffer2(ByVal sender As Object, ByVal args As QueryEventArgs)

      ' Set up the collection View Source in order to Sort the results of the query by DISTANCE       
                Dim cs As New CollectionViewSource
                cs.SortDescriptions.Add(New SortDescription("BUFFER_DISTANCE", ListSortDirection.Ascending)) 
                cs.Source = args.FeatureSet.Features        
     ' Apply the sort to the listbox       
                imageListBuffer.ItemsSource = cs.View        
     ' refresh the listbox        
                cs.View.Refresh()

        Dim featureSet As FeatureSet = args.FeatureSet
        imageListBuffer.ItemsSource = args.FeatureSet.Features

        ' Set the Buffer Variable for the Center Point of the buffer to a MAPPOINT not String to the variable being set 
        ' in the GeometryService_BufferCompleted2...the Variable is globally define at the to of the code page
        Dim _XYLocationBuffer As MapPoint = Nothing
        _XYLocationBuffer = _XYLocation

        If args.FeatureSet.Features.Count < 1 Then
            MessageBox.Show("No features found")
            Return
        End If
        For Each selectedGraphic As Graphic In args.FeatureSet.Features
            selectedGraphic.Symbol = TryCast(LayoutRoot.Resources("DefaultMarkerSymbol"), ESRI.ArcGIS.Client.Symbols.Symbol)
            _resultsGraphicsLayer.Graphics.Add(selectedGraphic)

            ' Get the center point of each selected graphic found in the buffer
            Dim c As ESRI.ArcGIS.Client.Geometry.MapPoint = selectedGraphic.Geometry.Extent.GetCenter()
            ' Call the GetDistance Function...Set the Distance to the BUFFER_DISTANCE variable for each graphic, for display in the listbox            
             selectedGraphic.Attributes("BUFFER_DISTANCE") = GetDistance(_XYLocationBuffer, c)
       
 Next selectedGraphic

    End Sub

Re: Collection View Source

MeConfused — Mon, 07 Feb 2011 19:13:28 GMT

Do I need to specify something in the xaml file? Or should this work the way it is?

Re: Collection View Source

JenniferNery — Mon, 07 Feb 2011 22:17:49 GMT

You can look at this sample for using CollectionViewSource http://msdn.microsoft.com/en-us/library/system.windows.data.collectionviewsource(v=VS.95).aspx. Notice that the PropertyName matches a property in the object collection.

What about using DataGrid or FeatureDataGrid where sorting comes for free. Look at this sample: http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#ToolkitFeatureDataGrid. FeatureDataGrid also work with GraphicsLayer, your GraphicsLayer can contain the resulting graphics which also include the new attribute buffer distance. Notice in the live sample, that you can click the header of the column and the column is sorted accordingly.

Re: Collection View Source

JayKappy — Tue, 08 Feb 2011 12:16:53 GMT

Thanks for your reply jennifer....

As for why I am not using a grid etc...I foudn that I can display more data in a confined location with a listbox, where I can format how I want the text to appear. When teh user does a search there are a series of windows that open along the bottom of my map...like this
http://coolapps.cybertech.com/AppGallery/Government_Service_Locator.aspx

Couple Thoughts:
In the example you pointed me to they have this line in the collection view source

Source="{StaticResource customerSampleData}">

I see that "customerSampleData" is defined above in this example...but in my app I have a listbox... My results are coming from a Query in my vb page ... I bind the results to the listbox with this
imageListBuffer.ItemsSource = args.FeatureSet.Features

I guess I am confused on how to make the connection from:
1. the listbox which is deifned in xaml
2. the binding of the results in the vb page
3. the assigning of the CVS in the xaml

Re: Collection View Source

MeConfused — Sat, 11 Dec 2021 11:55:56 GMT

Thanks for your reply jennifer....

As for why I am not using a grid etc...I foudn that I can display more data in a confined location with a listbox, where I can format how I want the text to appear. When the user does a search there are a series of windows that open along the bottom of my map...like this
http://coolapps.cybertech.com/AppGallery/Government_Service_Locator.aspx

Couple Thoughts:
In the example you pointed me to they have this line in the collection view source

Source="{StaticResource customerSampleData}">

imageListBuffer.ItemsSource = args.FeatureSet.Features

I guess I am confused on how to make the connection from:
1. the listbox which is defined in xaml
2. the binding of the results in the vb page to the listbox
3. the assigning of the CVS in the xaml to sort the listbox results

Right now I have this im my xaml page: I have no idea about the source when the source is in my VB page

    <UserControl.Resources>
        <!--<CollectionViewSource x:Name="dataSource" Source="{StaticResource imageListBuffer}">            
            <CollectionViewSource.SortDescriptions>
                <compMod:SortDescription PropertyName="NAME" Direction="Ascending"/>
            </CollectionViewSource.SortDescriptions>
        </CollectionViewSource>-->
    </UserControl.Resources>

<Grid Grid.Column="2">
      <StackPanel Orientation="Vertical" Margin="5" HorizontalAlignment="left" VerticalAlignment="top" >
            <Grid x:Name="IdentifyGridBuffer" HorizontalAlignment="left" VerticalAlignment="Top" Margin="0,2,0,0"  MouseEnter="TurnOnChurchBufferedGraphics">
                <Rectangle Fill="#CC5C90B2" Stroke="Gray" Opacity=".6" RadiusX="10" RadiusY="10" Margin="0,0,0,0" >
                    <Rectangle.Effect>
                        <DropShadowEffect/>
                    </Rectangle.Effect>
                </Rectangle>
                <StackPanel x:Name="IdentifyResultsPanelBuffer" Height="190" Width="300" Orientation="Vertical" Margin="0,20,0,0" HorizontalAlignment="Center">
                    <Grid x:Name="resultsPanelBuffer"  Width="260"  
                        HorizontalAlignment="Center" VerticalAlignment="Top"
                        Margin="10,40,10,10">
                        <Border Padding="2" Style="{StaticResource darkBorder}">
                            <StackPanel Orientation="Vertical" >
                                <ListBox x:Name="imageListBuffer" Height="120"   ScrollViewer.HorizontalScrollBarVisibility="Hidden" ScrollViewer.VerticalScrollBarVisibility="Visible" 
                                            BorderThickness="0"
                                            Foreground="White" Background="Transparent"
                                            SelectionChanged="imageListBuffer_SelectionChanged"
                                         ItemsSource="Binding Source={StaticResource dataSource}"  >
                                    <ListBox.ItemTemplate>
                                        <DataTemplate>
                                            <StackPanel Orientation="Horizontal" VerticalAlignment="Center" >
                                                <!-- QUERY -->
                                                <StackPanel Margin="1">
                                                    <TextBlock Foreground="White" Margin="0,4,0,0" VerticalAlignment="Center" Text="{Binding Attributes[TYPE]}"  />
                                                </StackPanel>
                                                <StackPanel Margin="5,0,0,0" Orientation="Vertical">
                                                    <TextBlock Foreground="White" Text="{Binding Attributes[NAME], StringFormat='Name:     \{0\}'}" >
                                                        <TextBlock.Effect>
                                                            <DropShadowEffect/>
                                                        </TextBlock.Effect>
                                                    </TextBlock>
                                                 </StackPanel>
                                            </StackPanel>
                                        </DataTemplate>
                                    </ListBox.ItemTemplate>
                                </ListBox>
                            </StackPanel>
                        </Border>
                    </Grid>
                </StackPanel>
            </Grid>
        </StackPanel>
</Grid>

VB PAGE - I have this in my vb page and nothing is happening

'..snip
        ' Set up the collection View Source in order to Sort the results of the query by DISTANCE
        Dim cs As New CollectionViewSource
        'cs.SortDescriptions.Add(New SortDescription("BUFFER_DISTANCE", ListSortDirection.Ascending))
        cs.SortDescriptions.Add(New SortDescription("NAME", ListSortDirection.Ascending))
        cs.Source = args.FeatureSet.Features
        ' Apply the sort to the listbox
        imageListBuffer.ItemsSource = cs.View
        ' refresh the listbox
        cs.View.Refresh()

        Dim featureSet As FeatureSet = args.FeatureSet
        ' Set the listbox with all the found features.

        imageListBuffer.ItemsSource = args.FeatureSet.Features
..snip

Re: Collection View Source

JenniferNery — Tue, 08 Feb 2011 15:49:47 GMT

In that MSDN sample, they defined their own class Customer and CustomerCollection. They did not show code-behind but it should be a simple class with properties that implements INotifyPropertyChanged and the collection is just an ObservableCollection. I think if you are going to use this approach, you need to create your own model class too with properties that you can sort by.

http://msdn.microsoft.com/en-us/library/system.componentmodel.inotifypropertychanged(v=VS.95).aspx
http://msdn.microsoft.com/en-us/library/system.windows.datatemplate(v=vs.95).aspx

Re: Collection View Source

MeConfused — Sat, 11 Dec 2021 11:55:59 GMT

WOW....I really have no idea what those two sites are saying...ALL that to simply sort results coming from a query into a listbox
So you are saying there is no other way to sort a listbox? This is the only way?
I am going to have to grab code from both links you sent to piece this all together?
If there was a way to put results from a query into a results windows and format how it shows, and makes the sorting easier then awesome...but this is the only way I see....

In their example they have this Customers Class...you saying that I have to create a class that houses over 20K customers in my city? This is where I am getting messed up...I have the results from a query that need to feed the listbox...not some created class that has hardcoded values....

Then create some other class that does something with INotifyPropertyChanged...

hmmm might have to rethink this one....anymore thoughts woudl be appreciated...

Public Class Customers
    Inherits ObservableCollection(Of Customer)

    Public Sub New()
        Add(New Customer("Michael", "Anderberg", "12 North Third Street, Apartment 45"))
        Add(New Customer("Chris", "Ashton", "34 West Fifth Street, Apartment 67"))
        Add(New Customer("Cassie", "Hicks", "56 East Seventh Street, Apartment 89"))
        Add(New Customer("Guido", "Pica", "78 South Ninth Street, Apartment 10"))
    End Sub

End Class

I DONT SEE any sorting....Where does the sorting happen in those two classes?

THanks Again

Re: Collection View Source

JenniferNery — Tue, 08 Feb 2011 18:28:32 GMT

I'm not saying this is the only way but your question was how to use CollectionViewSource so I gave you the links from MSDN. 🙂

You can also sort the results using Linq and use the sorted results as ListBox ItemsSource.

Re: Collection View Source

MeConfused — Sat, 11 Dec 2021 11:56:02 GMT

Thanks.....Lets start again....I am looking for teh simplest way to sort the results from a query that I have binded to a listbox...
Whats the easiest:confused:

Linq???

I am referencing this but cant convert to VB...I tried a converter but thats messing up...I think I am at least tryign to code in the correct location....grab the resulted set, sort, then bind?????

http://blogs.esri.com/Dev/blogs/silverlightwpf/archive/2010/01/20/Sorting-query-results-using-LINQ.aspx

I know I have the code all messed up....I just dont know what I am supposed to be targeting and setting..or if I am even on the right path here.
Query, Sort, Bind?

        Dim featureSet As FeatureSet = args.FeatureSet
        ' Set the listbox with all the found features.

        Dim enumGraphics = From SelectedGraphic In args.FeatureSet SetOrder By TryCast(SelectedGraphic.Attributes("NAME"), String) Ascending
        '  imageListBuffer.ItemsSource = args.FeatureSet.Features       
        imageListBuffer.ItemsSource = enumGraphics

        ' Private _XYLocation As MapPoint = Nothing
        Dim _XYLocationBuffer As MapPoint = Nothing
        _XYLocationBuffer = _XYLocation

        If args.FeatureSet.Features.Count < 1 Then
            MessageBox.Show("No features found")
            Return
        End If
        For Each selectedGraphic As Graphic In args.FeatureSet.Features
            'selectedGraphic.Symbol = TryCast(LayoutRoot.Resources("DefaultMarkerSymbol"), ESRI.ArcGIS.Client.Symbols.Symbol)
            selectedGraphic.Symbol = TryCast(LayoutRoot.Resources("StrobeMarkerSymbol_Blue"), ESRI.ArcGIS.Client.Symbols.Symbol)
            _resultsGraphicsLayer.Graphics.Add(selectedGraphic)
            'graphicsLayer.Graphics.Add(selectedGraphic)

            ' Get the center point of each selected graphic found in the buffer
            Dim c As ESRI.ArcGIS.Client.Geometry.MapPoint = selectedGraphic.Geometry.Extent.GetCenter()
            ' Call the GetDistance Function...Set the Distance to the BUFFER_DISTANCE variable for each graphic, for display in the listbox
            selectedGraphic.Attributes("BUFFER_DISTANCE") = GetDistance(_XYLocationBuffer, c)

        Next selectedGraphic

MAYBE THIS: Am I getting closer

Dim enumGraphics As FeatureSet = args.FeatureSet.OrderBy([NAME], String) Assending
imageListBuffer.ItemsSource = enumGraphics

Re: Collection View Source

JenniferNery — Sat, 11 Dec 2021 11:56:05 GMT

For me, I think Linq query might be the easiest solution. Once you have calculated and added the Distance, you can order by this attribute. You can then set ListBox ItemSource with the sortedGraphics.

var sortedGraphics = from g in graphicsLayer.Graphics
   orderby (double)g.Attributes["Distance"] ascending
   select g;

Re: Collection View Source

MeConfused — Sat, 11 Dec 2021 11:56:08 GMT

For me, I think Linq query might be the easiest solution. Once you have calculated and added the Distance, you can order by this attribute. You can then set ListBox ItemSource with the sortedGraphics.
var sortedGraphics = from g in graphicsLayer.Graphics
   orderby (double)g.Attributes["Distance"] ascending
   select g;

Thats in C# right? I was trying to convert it....thats from the example I posted right....
I know I am very close here...thanks to you
This is my feable attempt to convert that C# code....

Dim SortedList As FeatureSet = args.FeatureSet.OrderBy([Name],String)

Then set the ListBox
imageListBuffer.ItemsSource = SortedList
So LIKE this? I am so confused I dont know if its done before the IMageListBuffer Listbox gets binded or if its in the FOR EACH loop....

Would it go in the FOR EACH loop or above where the binding to the listbox occurs???

Re: Collection View Source

MeConfused — Tue, 08 Feb 2011 20:01:12 GMT

I AM THINKING that the dimented code I have above to do the sort should be right before the LIstBox binding....
THAT RIGHT?

Like THis

        Dim featureSet As FeatureSet = args.FeatureSet
        Dim SortedGraphics As Graphic = args.FeatureSet.OrderBy(selectedGraphic.Attributes([NAME], String)
        imageListBuffer.ItemsSource = SortedGraphics

THIS has to be close....ugggggg
??     Dim SortedGraphics As Graphic = args.FeatureSet.OrderBy("Name", ListSortDirection.Ascending)

Re: Collection View Source

JenniferNery — Sat, 11 Dec 2021 11:56:10 GMT

I'm not sure how correct the syntax is, I used http://www.developerfusion.com/tools/convert/csharp-to-vb/

Since you still need to calculate the distance of each graphic from the buffer point, you should do the following code after you have added this attribute for each graphic.

Dim sortedGraphics = From g In args.FeatureSet.Features Order By CDbl(g.Attributes("Distance")) Ascending
imageListBuffer.ItemsSource = sortedGraphics

Re: Collection View Source

JayKappy — Wed, 09 Feb 2011 12:01:12 GMT

Thank you once again....I knew I was getting close...things are starting to become more familar...And YES this was much easier than the CollectionViewSource...although I still may try that just to learn...

Questions: Which I hope you can shed some light on...

What does the 'g' represent? I just cant grasp that...I understand the args.FeatureSet.Features which comprise the results of the query...but the 'g' is confusing me...

Either or below and my data is returned to the listbox descending...thoughts?
For soem reason cant get it to ascend the order?

Thank you, your help is very much appreciated...So I guess the title of this forumn entry has now lost its meaning as I converted to Linq ...

        Dim sortedGraphics = From g In args.FeatureSet.Features Order By CDbl(g.Attributes("Distance")) Ascending

        Dim sortedGraphics = From g In args.FeatureSet.Features Order By CDbl(g.Attributes("Distance")) Descending

If I move to a string field I can get the sort to work properly....seems to be on this Distance field....hmmmmm

This works....
Dim sortedGraphics = From g In args.FeatureSet.Features Order By (g.Attributes("NAME")) Ascending

Re: Collection View Source

JayKappy — Wed, 09 Feb 2011 12:07:08 GMT

...............................................

Re: Collection View Source

JenniferNery — Wed, 09 Feb 2011 15:26:19 GMT

You can look at Linq samples here: http://msdn.microsoft.com/en-us/vbasic/bb737912#obydescsimp1

'g' in the Linq query is a temporary variable that represents element in your collection. It serves the same purpose as in foreach(var g in args.FeatureSet.Features).

If you convert the attribute value to string, the sort for (1,2,11) will be (1,11,2) because they will be treated as strings.

Re: Collection View Source

JayKappy — Sun, 12 Dec 2021 16:13:29 GMT

Thanks for the link....

I think you may have misunderstood me....I wasnt saying that I converted the value to a string...I used a string attribute "NAME" (string) instead of "Distance" (double)

        'Dim sortedGraphics = From g In args.FeatureSet.Features Order By (g.Attributes("NAME")) Ascending
        'Dim sortedGraphics = From g In args.FeatureSet.Features Order By (g.Attributes("NAME")) Descending

Using the String Attribute "NAME" the Ascending and Decending worked fine.

If I use the Distance (double) it was AWALYS is descending not matter if I specified Ascending or Descending...

BOTH OF THESE sort descending...was trying to fugure out why the Double wont sort Ascending...even if I specify "Ascending" as seen below

        Dim sortedGraphics = From g In args.FeatureSet.Features Order By CDbl(g.Attributes("DISTANCE")) Ascending       
        Dim sortedGraphics = From g In args.FeatureSet.Features Order By CDbl(g.Attributes("DISTANCE")) Descending

Re: Collection View Source

JenniferNery — Sat, 11 Dec 2021 11:56:13 GMT

I cannot replicate the same issue you are seeing with the following short sample:

private void GraphicsLayer_Initialized(object sender, EventArgs e)
{
 GraphicsLayer l = sender as GraphicsLayer;
 Graphic gr = new Graphic();
 gr.Attributes["Distance"] = 2.3;
 l.Graphics.Add(gr);

 gr = new Graphic();
 gr.Attributes["Distance"] = 4.0;
 l.Graphics.Add(gr);

 gr = new Graphic();
 gr.Attributes["Distance"] = 2.3;
 l.Graphics.Add(gr);

 gr = new Graphic();
 gr.Attributes["Distance"] = 3.2;
 l.Graphics.Add(gr);

 gr = new Graphic();
 gr.Attributes["Distance"] = 1.0;
 l.Graphics.Add(gr);

 var sortedGraphics = from g in l.Graphics
   orderby (double) g.Attributes["Distance"] ascending
   select g;
 myList.ItemsSource = sortedGraphics;
}

<ListBox x:Name="myList" VerticalAlignment="Top" HorizontalAlignment="Center" >
 <ListBox.ItemTemplate>
  <DataTemplate>
   <TextBlock Text="{Binding Attributes[Distance]}"/>
  </DataTemplate>
 </ListBox.ItemTemplate>
</ListBox>

Maybe the C# to VB conversion was wrong?

Re: Collection View Source

JayKappy — Sun, 12 Dec 2021 16:13:31 GMT

Think I found it....I had the Linq before the code that added the graphics and called the Distance function to calculate it.

I moved it below and bam...it worked....THANK YOU VERY MUCH FOR YOUR HELP...sooooo very appreciated...
I remembered you saying to do the sort after I calculated the distances.....THANK you again


        Dim featureSet As FeatureSet = args.FeatureSet

' CODE WAS HERE        

        Dim _XYLocationBuffer As MapPoint = Nothing
        _XYLocationBuffer = _XYLocation

        If args.FeatureSet.Features.Count < 1 Then
            MessageBox.Show("No features found")
            Return
            End If
        For Each selectedGraphic As Graphic In args.FeatureSet.Features
                'selectedGraphic.Symbol = TryCast(LayoutRoot.Resources("DefaultMarkerSymbol"), ESRI.ArcGIS.Client.Symbols.Symbol)
            selectedGraphic.Symbol = TryCast(LayoutRoot.Resources("StrobeMarkerSymbol_Blue"), ESRI.ArcGIS.Client.Symbols.Symbol)
            _resultsGraphicsLayer.Graphics.Add(selectedGraphic)
                'graphicsLayer.Graphics.Add(selectedGraphic)

                ' Get the center point of each selected graphic found in the buffer
            Dim c As ESRI.ArcGIS.Client.Geometry.MapPoint = selectedGraphic.Geometry.Extent.GetCenter()
                ' Call the GetDistance Function...Set the Distance to the BUFFER_DISTANCE variable for each graphic, for display in the listbox
            selectedGraphic.Attributes("DISTANCE") = GetDistance(_XYLocationBuffer, c)

        Next selectedGraphic

' NOW HERE        
       Dim sortedGraphics = From g In args.FeatureSet.Features Order By CDbl(g.Attributes("DISTANCE")) Ascending
        imageListBuffer.ItemsSource = sortedGraphics

Re: Collection View Source

JayKappy — Wed, 09 Feb 2011 16:49:24 GMT

Anyone have any questions please feel free to contact me...

MeConfused1982@yahoo.com

Thanks again Jennifer