ArcGIS Runtime- C# - Click on a polyline and select it to change color

MichaelSibilio — Thu, 17 Sep 2015 15:46:43 GMT

I'm playing with the ArcGIS runtime SDK for .NET. I want to be able to generate multiple polylines in code, the be able to later select them in the map with a mouse click and change the colors. Any idea how to accomplish this?

Re: ArcGIS Runtime- C# - Click on a polyline and select it to change color

ThadTilton — Thu, 17 Sep 2015 17:41:54 GMT

Hi Michael -

One way to accomplish this would be to display the lines as graphics. Unlike other types of layers, a GraphicsOverlay (or GraphicsLayer) will allow you to assign individual symbols to each graphic (as opposed to assigning a renderer for the entire layer, ie). You could perform a hit test on the graphics (on MapViewTapped, eg.) and update the symbol (color) for the line that the user selects.

Here's an example (including a button handler for creating the lines):

XAML:

<Grid>

<esri:MapView x:Name="MyMapView"

LayerLoaded="MyMapView_LayerLoaded">

<esri:MapView.GraphicsOverlays>

<esri:GraphicsOverlay ID="MyLineGraphics">

<esri:GraphicsOverlay.Renderer>

<esri:SimpleRenderer>

<esri:SimpleLineSymbol Color="DarkGray" Width="2" Style="Dash"/>

</esri:SimpleRenderer>

</esri:GraphicsOverlay.Renderer>

</esri:GraphicsOverlay>

</esri:MapView.GraphicsOverlays>

<esri:Map>

<esri:ArcGISTiledMapServiceLayer ID="Basemap"

ServiceUri="http://services.arcgisonline.com/ArcGIS/rest/services/World_Topo_Map/MapServer"/>

</esri:Map>

</esri:MapView>

<Button x:Name="AddLineButton"

Content="Add Line ..."

Click="AddLineButton_Click"/>

</StackPanel>

</Grid>

Code behind (C#):

public partial class MainWindow : Window

{

private SimpleLineSymbol _lineSymbol;

public MainWindow()

{

InitializeComponent();

MyMapView.MapViewTapped += MyMapView_MapViewTapped;

}

// Do a hit test when the map view is tapped

// change the color of the selected graphic (polyline)

async void MyMapView_MapViewTapped(object sender, MapViewInputEventArgs e)

{

var graphicsOverlay = MyMapView.GraphicsOverlays["MyLineGraphics"];

var graphic = await graphicsOverlay.HitTestAsync(MyMapView, e.Position);

if (graphic != null)

{

// Line symbol color is controlled by a radio button choice

graphic.Symbol = _lineSymbol;

}

// Button click handler to add lines (with the default gray symbol)

private async void AddLineButton_Click(object sender, RoutedEventArgs e)

{

var newLine = await MyMapView.Editor.RequestShapeAsync(DrawShape.Polyline);

var newGraphic = new Graphic(newLine);

var graphicsOverlay = MyMapView.GraphicsOverlays["MyLineGraphics"];

graphicsOverlay.Graphics.Add(newGraphic);

}

// Radio button handler to determine the line color when a line is clicked

private void RadioButton_Checked(object sender, RoutedEventArgs e)

{

_lineSymbol = new SimpleLineSymbol

{

Style = SimpleLineStyle.Solid,

Width = 2

};

var rb = sender as RadioButton;

switch (rb.Content.ToString())

{

case "Red":

_lineSymbol.Color = Colors.Red;

break;

case "Green":

_lineSymbol.Color = Colors.Green;

break;

case "Blue":

_lineSymbol.Color = Colors.Blue;

break;

default:

break;

}

Re: ArcGIS Runtime- C# - Click on a polyline and select it to change color

MichaelSibilio — Fri, 18 Sep 2015 11:37:56 GMT

Thank you very much for the detailed example! Greatly appreciated.

topic Re: ArcGIS Runtime- C# - Click on a polyline and select it to change color in .NET Maps SDK Questions

ArcGIS Runtime- C# - Click on a polyline and select it to change color

Re: ArcGIS Runtime- C# - Click on a polyline and select it to change color

Re: ArcGIS Runtime- C# - Click on a polyline and select it to change color