Manage operational layers

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
// Copyright 2019 Esri.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
// You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific
// language governing permissions and limitations under the License.

using Esri.ArcGISRuntime.Mapping;
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;

namespace ArcGIS.WPF.Samples.ManageOperationalLayers
{
    [ArcGIS.Samples.Shared.Attributes.Sample(
        name: "Manage operational layers",
        category: "Map",
        description: "Add, remove, and reorder operational layers in a map.",
        instructions: "When the app starts, a list displays the operational layers that are currently displayed in the map. Right-click on the list item to remove the layer, or left-click to move it to the top. The map will be updated automatically.",
        tags: new[] { "add", "delete", "layer", "map", "remove" })]
    public partial class ManageOperationalLayers
    {
        // The view model manages the data for the sample.
        private MapViewModel _viewModel;

        // During drag and drop, keep track of which list the dragged item came from.
        private ListBoxItem _originatingListBoxItem;

        // Some URLs of layers to add to the map.
        private readonly string[] _layerUrls = new[]
        {
            "https://sampleserver5.arcgisonline.com/arcgis/rest/services/Elevation/WorldElevations/MapServer",
            "https://sampleserver5.arcgisonline.com/arcgis/rest/services/Census/MapServer",
            "https://sampleserver5.arcgisonline.com/arcgis/rest/services/DamageAssessment/MapServer"
        };

        public ManageOperationalLayers()
        {
            InitializeComponent();
            Initialize();
        }

        private void Initialize()
        {
            _viewModel = new MapViewModel(new Map(BasemapStyle.ArcGISStreets));

            // Configure bindings to point to the view model.
            this.DataContext = _viewModel;

            // Add the layers.
            foreach (string layerUrl in _layerUrls)
            {
                _viewModel.AddLayerFromUrl(layerUrl);
            }
        }

        #region Drag and drop support

        private void ListBox_DragPreviewMove(object sender, MouseButtonEventArgs e)
        {
            // This method is called when the user clicks and starts dragging a listbox item.

            if (sender is ListBoxItem)
            {
                // Get the listbox item that is being moved.
                ListBoxItem sendingItem = (ListBoxItem)sender;

                // Record that this item was being dragged - used later when drag ends to determine which item to move.
                _originatingListBoxItem = sendingItem;

                // Register the start of the drag & drop operation with the system.
                DragDrop.DoDragDrop(sendingItem, sendingItem.DataContext, DragDropEffects.Move);

                // Mark the dragged item as selected.
                sendingItem.IsSelected = true;
            }
        }

        private void ListBoxItem_OnDrop(object sender, DragEventArgs e)
        {
            // This method is called when the user finishes dragging while over the listbox.

            // Find the source and destination list boxes.
            ListBox sourceBox = FindParentListBox(_originatingListBoxItem);
            if (sourceBox == null)
            {
                // Return if the source isn't valid - happens when duplicate events are raised.
                return;
            }

            // Find the list box that the item was dropped on (i.e. dragged to).
            ListBox destinationBox = FindParentListBox((UIElement)sender);

            // Get the data that is being dropped.
            Layer draggedData = (Layer)e.Data.GetData(typeof(ArcGISMapImageLayer));

            // Find where in the respective lists the items are.
            int indexOfRemoved = sourceBox.Items.IndexOf(draggedData);
            int indexOfInsertion;

            // Sender is the control that the item is being dropped on. Could be a listbox or a listbox item.
            if (sender is ListBoxItem)
            {
                // Find the layer that the item represents.
                Layer targetData = ((ListBoxItem)sender).DataContext as Layer;

                // Find the position of the layer in the listbox.
                indexOfInsertion = destinationBox.Items.IndexOf(targetData);
            }
            else if (destinationBox != sourceBox)
            {
                // Drop the item at the end of the list if the user let go of the item on the empty space in the box rather than the list item.
                // This works because both the listbox and its individual listbox items participate in drag and drop.
                indexOfInsertion = destinationBox.Items.Count - 1;
            }
            else
            {
                return;
            }

            // Find the appropriate source and destination boxes.
            LayerCollection sourceList = sourceBox == IncludedListBox ? _viewModel.IncludedLayers : _viewModel.ExcludedLayers;
            LayerCollection destinationList = destinationBox == IncludedListBox ? _viewModel.IncludedLayers : _viewModel.ExcludedLayers;

            // Return if there is nothing to do.
            if (sourceList == destinationList && indexOfRemoved == indexOfInsertion)
            {
                return;
            }

            if (sourceBox == destinationBox && indexOfRemoved < indexOfInsertion)
            {
                indexOfInsertion -= 1;
            }

            // Perform the move.
            sourceList.RemoveAt(indexOfRemoved);
            destinationList.Insert(indexOfInsertion + 1, draggedData);
        }

        private static ListBox FindParentListBox(UIElement source)
        {
            // This is needed because it is hard to tell which listbox an item belongs to.

            // Walk up the visual element tree until a ListBox is found.
            UIElement parentElement = source;
            // While the parent element is not a listbox and the parent element is not null,
            while (!(parentElement is ListBox) && parentElement != null)
            {
                // find the next parent.
                parentElement = VisualTreeHelper.GetParent(parentElement) as UIElement;
            }

            return parentElement as ListBox;
        }

        #endregion Drag and drop support
    }

    internal class MapViewModel
    {
        public Map Map { get; set; }

        public LayerCollection IncludedLayers
        {
            get { return Map.OperationalLayers; }
        }

        public LayerCollection ExcludedLayers { get; set; }

        public MapViewModel(Map map)
        {
            Map = map;
            ExcludedLayers = new LayerCollection();
        }

        public void AddLayerFromUrl(string layerUrl)
        {
            ArcGISMapImageLayer layer = new ArcGISMapImageLayer(new Uri(layerUrl));
            Map.OperationalLayers.Add(layer);
        }
    }
}