topic Re: about after using measure behavior, the graph can't stay in the map in ArcGIS API for Silverlight Questions

about after using measure behavior, the graph can't stay in the map

DanDong — Tue, 28 Sep 2010 19:05:49 GMT

Hi,

I want to ask a question about how to make the polygon stay in the map after using the measure function. I mean I use the measure function to measure the distance of each side of a polygon(measuremode="polygon"), but when I double click the last vertex, the polygon disappear?? I want to keep this polygon. What should I add in the xmal file and cs file? Thank you very much!

Re: about after using measure behavior, the graph can't stay in the map

JenniferNery — Sat, 11 Dec 2021 18:29:09 GMT

You must be referring to MeasureAction. The GraphicsLayer that contains the polygon used for Measure is added to the map once Measure is started and removed from the map once Measure has completed.

If you need this polygon to stay in your map, you need to create your own GraphicsLayer and add a copy of this polygon to your GraphicsLayer. Maybe do something like the following: Note, however, that this code will be executed everytime a new layer is added to your map. You might need to tweak this to handle when you subscribe/unsubscribe to Graphics.CollectionChanged event.
Xaml-code:

  <esri:Map x:Name="MyMap">
   <esri:ArcGISTiledMapServiceLayer ID="MyBaseLayer" 
                Url="http://services.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer" />
   <esri:GraphicsLayer ID="MyGraphicsLayer"/>
  </esri:Map>

Code-behind:

this.MyMap.Layers.CollectionChanged += new System.Collections.Specialized.NotifyCollectionChangedEventHandler(Layers_CollectionChanged);
  }

  void Layers_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
  {
   if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
   {
    foreach(var item in e.NewItems)
     if(item is GraphicsLayer)
      (item as GraphicsLayer).Graphics.CollectionChanged += new System.Collections.Specialized.NotifyCollectionChangedEventHandler(Graphics_CollectionChanged);
   }
  }

  void Graphics_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
  {
   if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
   {
    GraphicsLayer graphicsLayer = this.MyMap.Layers["MyGraphicsLayer"] as GraphicsLayer;
    if (graphicsLayer != null)
    {
     foreach (var item in e.NewItems)
     {
      if (item is Graphic)
      {
       Graphic g = item as Graphic;
       graphicsLayer.Graphics.Add(new Graphic() { Geometry = g.Geometry, Symbol = g.Symbol });
      }
     }
    }
   }
  }

Re: about after using measure behavior, the graph can't stay in the map

DanDong — Tue, 28 Sep 2010 21:59:27 GMT

Thank you very much for the help. I was however trying to implement the code using c# and was errors due to my unfamiliarity with the language. Could you help me out by converting the code to c#?

Thanks so much.

Re: about after using measure behavior, the graph can't stay in the map

JenniferNery — Wed, 29 Sep 2010 00:46:45 GMT

I'm assuming you already looked at this sample for MeasureAction:http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#UtilityActions

In addition to this sample, you can add the code I posted below. It is already in C#.

Re: about after using measure behavior, the graph can't stay in the map

DanDong — Wed, 29 Sep 2010 01:13:23 GMT

I'm assuming you already looked at this sample for MeasureAction:http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#UtilityActions

In addition to this sample, you can add the code I posted below. It is already in C#.

Hi, yes, I'v already seen the sample, but in the sample, when you double click the last vertex, the graph will disappear too.

I can't see the code you posted below, sorry, can you post it again? Thanks a lot!

Re: about after using measure behavior, the graph can't stay in the map

JenniferNery — Wed, 29 Sep 2010 03:03:59 GMT

Kindly see post #2 for the additional code.

Re: about after using measure behavior, the graph can't stay in the map

DanDong — Thu, 30 Sep 2010 17:37:30 GMT

Kindly see post #2 for the additional code.

Thank you so much! It works!:)

Re: about after using measure behavior, the graph can't stay in the map

PatrickBrooke — Tue, 05 Oct 2010 21:04:15 GMT

OK,

It may just be me, but this code snippet only captures the polyline(s), not the fill polygon. It appears that what happens is when the graphic is first added by measure action, it only adds the fill polygon on the initial click, at which time the geometry of the fill polygon is not known to the system so it cannot tell my new graphics layer what it's geometry is when I finish drawing.

Is there an easy way to get that fill polygon? I can think of a difficult way to do it maybe, but not an easy way. Help?

Re: about after using measure behavior, the graph can't stay in the map

JenniferNery — Wed, 06 Oct 2010 22:36:19 GMT

You are right, in this sample, what gets added are Point and Polyline features only. The snippet here was meant to be a guideline on how you can retain the graphics in your map if the layer that contained them were added/removed by some means. I added a note in my previous post that the code also needs some tweaking 🙂

Adding the fill of the polygon and its additional area information to your GraphicsLayer is not something you can do with our API at this point. This sounds like an enhancement request that I need to forward to our team lead.

Re: about after using measure behavior, the graph can't stay in the map

JenniferNery — Thu, 07 Oct 2010 20:01:51 GMT

Here's the answer I got after talking to our lead:

MeasureAction is designed to remove the graphic from the map after it is done. Should you need the graphic to stay in your map, you can use Draw object for that. Retaining the graphic drawn with MeasureAction is not supported.

Re: about after using measure behavior, the graph can't stay in the map

PatrickBrooke — Fri, 08 Oct 2010 21:25:08 GMT

Thank you for looking in to that Jennifer,

That is an unfortunate design since I cannot think of anyone would would prefer that behavior, they would only tolerate this behavior.

I currently do use the draw object for measure at this time, its performace is lacking since it does not dynamically track the measurements of a line as does the measure action(Though I could build a tool that does this, but the time involved...). Measure action is almost prefect but lacking nonetheless!!!

I was able to capture the polygon eventually using your code, but what happened was everything would be added to my new graphics layer every time I added a new point, so I had multiple instances of the measurement text on the each line. What I did was capture the graphicslayer added by measure action to the map instead of using the graphics added event "newitems" property. Each time the event fired(when I added a measure point) I added all of the graphics from the measure action graphics layer to my new one. This led to the duplication of graphics in my new one. Not acceptable!

You know what is even more unfortunate? I was soo close to getting this to work, but it appears that when the graphics layer is removed after the measure action is complete, the graphics layer is cleared prior. That ruins everything. I had measure graphic layer stored in a new graphics layer on the map so I could copy the measure graphics in at the end of the measure, but the graphics layer is emptied before it is removed, so I lose all of the graphics!!! Sooo close.... If they just did not clear the graphics layer before removing it!!! A work around would exist!

Thanks again, and I hope the designers/developers see what a limitation this puts on the measure action. Such potential from this tool, but... :rolleyes:

Re: about after using measure behavior, the graph can't stay in the map

PatrickBrooke — Sat, 11 Dec 2021 18:29:11 GMT

Ok,

I did the impossible. I got my application to keep the measure action graphics layer after the draw completes(user double clicks).

What this does is add the existing graphics from the added graphics layer (not from the CollectionChangedEventArgs.NewItems property) to a new graphics layer I put on my map. Then each time the user clicks, that graphics layer is cleared, and the next state of the measure action graphics layer is added to that graphics layer. It is cleared each time until the the double click, where a global bool tracks if the user double clicked. If that bool is satisfied, the graphics layer is not cleared, and you are left with the final state of the measure action graphics layer. Easy, right!?

I had an epiphany over the weekend and the logic worked through my head, and wouldn't you know it, it works great!! I out smarted measure action, and now it is finally worth something to me!

If you want to try my this implementation of measure action, go to http://gis.modestogov.com

My users will be happy!!!!!

Patrick

private GraphicsLayer addedLayer;
private GraphicsLayer graphicsLayer;

void Layers_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
           
            if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
            {
                foreach (var item in e.NewItems)
                    if (item is GraphicsLayer)
                    {
                        addedLayer = item as GraphicsLayer;
                        graphicsLayer = this.MyMap.Layers["MeasureGraphicsLayer"] as GraphicsLayer;
                        graphicsLayer.Visible = false;
                        
                        (item as GraphicsLayer).Graphics.CollectionChanged += new System.Collections.Specialized.NotifyCollectionChangedEventHandler(Graphics_CollectionChanged);
                    }
            }

            if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Remove)
            { 
               if (addedLayer != null)
                {
                    isDrawOver = true;
                    graphicsLayer.Visible = true;
                }
            }

        
  }

        void Graphics_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
           
            if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
            {
                glCollectionChanged = true;

                if (isDrawOver == false)
                {
                    graphicsLayer.ClearGraphics();                    
                }

                else 
                {
                    isDrawOver = false;
                  
                }

                if (graphicsLayer != null)
                {
                    foreach (Graphic item in addedLayer.Graphics)
                    {                        
                        Graphic g = item as Graphic;
                        graphicsLayer.Graphics.Add(new Graphic() { Geometry = g.Geometry, Symbol = g.Symbol });                        
                    }                   
                }
            }
        }

Re: about after using measure behavior, the graph can't stay in the map

DanDong — Wed, 13 Oct 2010 04:56:35 GMT

Ok,

I did the impossible. I got my application to keep the measure action graphics layer after the draw completes(user double clicks).

What this does is add the existing graphics from the added graphics layer (not from the CollectionChangedEventArgs.NewItems property) to a new graphics layer I put on my map. Then each time the user clicks, that graphics layer is cleared, and the next state of the measure action graphics layer is added to that graphics layer. It is cleared each time until the the double click, where a global bool tracks if the user double clicked. If that bool is satisfied, the graphics layer is not cleared, and you are left with the final state of the measure action graphics layer. Easy, right!?

I had an epiphany over the weekend and the logic worked through my head, and wouldn't you know it, it works great!! I out smarted measure action, and now it is finally worth something to me!

If you want to try my this implementation of measure action, go to http://gis.modestogov.com

My users will be happy!!!!!

Patrick

Thank you Patrick, it really helps me a lot. I have a little question.

bool isDrawOver = true;
bool glCollectionChanged = true;

Those two bool variables have the initial of True right?

Re: about after using measure behavior, the graph can't stay in the map

PatrickBrooke — Wed, 13 Oct 2010 21:35:27 GMT

isDrawOver should always be false except when the measure graphics layer is removed (true), then it is reset to false waiting for the next measure to happen. I simply use that so I can track when the user is done measuring, so then I freeze the graphics layer and then make it visible.

you should not need glCollectionChanged, I used this to meet the need of my specific application, you should just delete that out.

Re: about after using measure behavior, the graph can't stay in the map

DanDong — Mon, 18 Oct 2010 12:30:10 GMT

isDrawOver should always be false except when the measure graphics layer is removed (true), then it is reset to false waiting for the next measure to happen. I simply use that so I can track when the user is done measuring, so then I freeze the graphics layer and then make it visible.

you should not need glCollectionChanged, I used this to meet the need of my specific application, you should just delete that out.

Thank you. I have another question. How do you make sure in the process of measuring, the graphic is first drawn on addedlayer, then from added layer it is added to the graphicslayer.

Re: about after using measure behavior, the graph can't stay in the map

PatrickBrooke — Sat, 11 Dec 2021 18:29:14 GMT

If I am understanding your question, that happens here when the measure tool is first activated

if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
   {
                foreach (var item in e.NewItems)
                    if (item is GraphicsLayer)
                    {
                        addedLayer = item as GraphicsLayer;
                        graphicsLayer = this.MyMap.Layers["MeasureGraphicsLayer"] as GraphicsLayer;
                        graphicsLayer.Visible = false;
                  
 }

Then I simply copy the graphics from added layer to graphicslayer. addedlayer is set to the graphic that the measure tool adds to the map, every time the tool is invoked. graphicslayer is a layer that I put on the map and is loaded when the map initializes.

I am not sure I answered your question.

Re: about after using measure behavior, the graph can't stay in the map

DanDong — Sat, 11 Dec 2021 18:29:16 GMT

If I am understanding your question, that happens here when the measure tool is first activated
if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
   {
                foreach (var item in e.NewItems)
                    if (item is GraphicsLayer)
                    {
                        addedLayer = item as GraphicsLayer;
                        graphicsLayer = this.MyMap.Layers["MeasureGraphicsLayer"] as GraphicsLayer;
                        graphicsLayer.Visible = false;
                  
 }
Then I simply copy the graphics from added layer to graphicslayer. addedlayer is set to the graphic that the measure tool adds to the map, every time the tool is invoked. graphicslayer is a layer that I put on the map and is loaded when the map initializes.

I am not sure I answered your question.

Yes. I think I get it. Thank you very much! 😛

Re: about after using measure behavior, the graph can't stay in the map

BrandonCales — Mon, 23 Apr 2012 18:05:02 GMT

I have this working...thanks Patrick.

How are you reactivating the Measure, so once the prior measure is shown on the graphics layer and new MeasureAction begins?

Also...does anyone know of a way to cancel Measure in the middle of running it?

Re: about after using measure behavior, the graph can't stay in the map

BrandonCales — Sat, 11 Dec 2021 18:29:19 GMT

Here is my code for this - it works well, however all I want to do is allow the user to measure again without having to click on the tool again.

.xaml

<!-- Measure Tools Window-->
        <userControls:WindowPanel x:Name="MeasureTools" HorizontalAlignment="Left" Margin="420,10,0,0" VerticalAlignment="Top"  IsOpen="{Binding ElementName=ToolsMenu_Measure, Path=IsChecked, Mode=TwoWay}">
                    <StackPanel Orientation="Vertical" Margin="5">
                    <StackPanel Orientation="Horizontal" Margin="5">
                    <RadioButton Content="Distance"
       ToolTipService.ToolTip="Distance"
       GroupName="MeasureMode"
       Margin="5,0,0,0" Foreground="White" FontSize="11" Click="MeasureTools_Click">
                            <!--<i:Interaction.Triggers>
                                <i:EventTrigger EventName="Click">
                                    <esri:MeasureAction                                  
                                    AreaUnit="SquareMiles"
                                    DisplayTotals="True"
                                    DistanceUnit="Miles"
                                    MapUnits="Feet"
                                    MeasureMode="Polyline"                                   
                                    FillSymbol="{StaticResource DefaultFillSymbol}"
                                    TargetName="MyMap"/>
                                </i:EventTrigger>
                            </i:Interaction.Triggers>-->
                        </RadioButton>
                        <RadioButton Content="Area"
       ToolTipService.ToolTip="Area"
       GroupName="MeasureMode"
       Margin="5,0,0,0" Foreground="White" FontSize="11" Click="MeasureTools_Click">
                            <!--<i:Interaction.Triggers>
                                <i:EventTrigger EventName="Click">
                                    <esri:MeasureAction                                  
                                    AreaUnit="SquareMiles"
                                    DisplayTotals="True"
                                    DistanceUnit="Miles"
                                    MapUnits="Feet"
                                    MeasureMode="Polygon"                                   
                                    FillSymbol="{StaticResource DefaultFillSymbol}"
                                    TargetName="MyMap" />
                                </i:EventTrigger>
                            </i:Interaction.Triggers>-->
                        </RadioButton>
                        <RadioButton Content="Clear"
       ToolTipService.ToolTip="Clear" IsChecked="True"
       GroupName="MeasureMode"
       Margin="5,0,0,0" Foreground="White" FontSize="11" Click="MeasureTools_Click">
                    </RadioButton>
                    </StackPanel>
                    <TextBlock Foreground="Yellow" FontSize="11" 
                               Text="Double-Click to Complete" TextWrapping="NoWrap" Height="Auto" 
                               HorizontalAlignment="Center" Margin="5,3,0,0" FontStyle="Italic" />
                    </StackPanel>
                    <userControls:WindowPanel.ContentTitle>
                        <StackPanel Orientation="Horizontal">
                            <Image Source="Images/icons/i_measure.png" 
                           HorizontalAlignment="Left" VerticalAlignment="Top" Stretch="Fill" 
                           Width="20" Height="20" Margin="5,2,0,0" />
                            <TextBlock Foreground="White" FontSize="12" 
                               Text="Measure" Width="100" TextWrapping="NoWrap" Height="Auto" 
                               HorizontalAlignment="Left" Margin="5,3,0,0" />
                        </StackPanel>
                    </userControls:WindowPanel.ContentTitle>
        </userControls:WindowPanel>

.cs

#region MeasureTool
            private GraphicsLayer addedLayer;
            private GraphicsLayer MeasureGraphicsLayer;
            private myMeasureAction ma = new myMeasureAction();
            private string MeasureTool = null;


            private class myMeasureAction : ESRI.ArcGIS.Client.Actions.MeasureAction
            {
                public void Execute()
                {
                    Invoke(null);
                }
            }

            private void MeasureTools_Click(object sender, System.Windows.RoutedEventArgs e)
            {
                if ((RadioButton)sender != null)
                {
                    MeasureTool = ((RadioButton)sender).Content.ToString();

                    MeasureGraphicsLayer = this.MyMap.Layers["MeasureGraphicsLayer"] as GraphicsLayer;
                    MeasureGraphicsLayer.ClearGraphics();
                    MeasureGraphicsLayer.Visible = false;

                    ma.DisplayTotals = true;
                    ma.AreaUnit = ESRI.ArcGIS.Client.Actions.AreaUnit.SquareMiles;
                    ma.DistanceUnit = ESRI.ArcGIS.Client.Actions.DistanceUnit.Miles;
                    ma.FillSymbol = LayoutRoot.Resources["DefaultFillSymbol"] as FillSymbol;
                    ma.Attach(MyMap);

                    //MeasureTool = ((RadioButton)sender).Content.ToString();

                    if (MeasureTool == "Distance")
                    {
                        ma.MeasureMode = myMeasureAction.Mode.Polyline;
                        ma.Execute();
                    }
                    else if (MeasureTool == "Area")
                    {
                        ma.MeasureMode = myMeasureAction.Mode.Polygon;
                        ma.Execute();
                    }
                    else
                    {
                        MeasureGraphicsLayer.ClearGraphics();
                        MeasureGraphicsLayer.Visible = false;
                        ma.Detach();
                    }
                }   
            }

            private void MeasureTools_Clear_Click(object sender, RoutedEventArgs e)
            {
                MeasureGraphicsLayer.ClearGraphics();
                MeasureGraphicsLayer.Visible = false;
                ma.Detach();
            }

            private void Layers_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
            {
                if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
                {
                    foreach (var item in e.NewItems)
                    {
                        if (item is GraphicsLayer)
                        {
                            addedLayer = item as GraphicsLayer;
                            MeasureGraphicsLayer = this.MyMap.Layers["MeasureGraphicsLayer"] as GraphicsLayer;
                            MeasureGraphicsLayer.Visible = false;

                            (item as GraphicsLayer).Graphics.CollectionChanged += Graphics_CollectionChanged;
                        }
                    }
                }
                if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Remove)
                {
                    if (addedLayer != null)
                    {
                        isDrawOver = true;
                        MeasureGraphicsLayer.Visible = true;

                        //Tried to rerun here....but error
                    }
                }
            }

            private void Graphics_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
            {
                if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
                {
                    if (isDrawOver == false)
                    {
                        MeasureGraphicsLayer.ClearGraphics();
                    }
                    else
                    {
                        isDrawOver = false;
                    }

                    if (MeasureGraphicsLayer != null)
                    {
                        foreach (Graphic item in addedLayer.Graphics)
                        {
                            Graphic g = item as Graphic;
                            MeasureGraphicsLayer.Graphics.Add(new Graphic() { Geometry = g.Geometry, Symbol = g.Symbol });
                        }
                    }
                }
                else
                {
                    //MessageBox.Show(e.Action.ToString());
                }
            }
        #endregion

Re: about after using measure behavior, the graph can't stay in the map

EkaterinaTitova — Sat, 11 Dec 2021 18:29:22 GMT

private GraphicsLayer addedLayer;
private GraphicsLayer graphicsLayer;

void Layers_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
           
            if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
            {
                foreach (var item in e.NewItems)
                    if (item is GraphicsLayer)
                    {
                        addedLayer = item as GraphicsLayer;
                        graphicsLayer = this.MyMap.Layers["MeasureGraphicsLayer"] as GraphicsLayer;
                        graphicsLayer.Visible = false;
                        
                        (item as GraphicsLayer).Graphics.CollectionChanged += new System.Collections.Specialized.NotifyCollectionChangedEventHandler(Graphics_CollectionChanged);
                    }
            }

            if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Remove)
            { 
               if (addedLayer != null)
                {
                    isDrawOver = true;
                    graphicsLayer.Visible = true;
                }
            }

        
  }

        void Graphics_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
           
            if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
            {
                glCollectionChanged = true;

                if (isDrawOver == false)
                {
                    graphicsLayer.ClearGraphics();                    
                }

                else 
                {
                    isDrawOver = false;
                  
                }

                if (graphicsLayer != null)
                {
                    foreach (Graphic item in addedLayer.Graphics)
                    {                        
                        Graphic g = item as Graphic;
                        graphicsLayer.Graphics.Add(new Graphic() { Geometry = g.Geometry, Symbol = g.Symbol });                        
                    }                   
                }
            }
        }

Can you help please, why this decision doesn't work for myMeasureAction.MeasureMode = MeasureAction.Mode.Radius? Procedure Graphics_CollectionChanged is never started...