LayerBase.DataLoaded Event

Occurs after the data has been loaded into a map layer.

Namespace: DevExpress.XtraMap

Assembly: DevExpress.XtraMap.v18.2.dll

Declaration

C#

public event DataLoadedEventHandler DataLoaded

VB.NET

Public Event DataLoaded As DataLoadedEventHandler

Event Data

The DataLoaded event's data class is DataLoadedEventArgs.

Remarks

Handle the DataLoaded event to ensure that the data is loaded completely into a map layer.

Example

This example shows how to visualize the progress of loading image tiles from the OpenStreetMap data provider using a progress bar.

To accomplish this task, handle the ImageLayer.RequestDataLoading event and specify how the progress bar should be updated using the UpdateProgressBar method. Then, handle the LayerBase.DataLoaded event to specify the final state of the progress bar when the data load is finished.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/how-to-show-the-progress-of-loading-image-tiles-e5183

Form1.cs

using DevExpress.XtraMap;
using System;
using System.Windows.Forms;

namespace TilesLoaded {
    public partial class Form1 : Form {
        int requestsCounter = 0;
        ImageLayer Layer { get { return (ImageLayer)mapControl1.Layers[0]; } }

        public Form1() {
            InitializeComponent();
            Layer.RequestDataLoading += Layer_RequestDataLoading;
            Layer.DataLoaded += Layer_DataLoaded;
        }

        void Layer_RequestDataLoading(object sender, EventArgs e) {
            requestsCounter++;
            UpdateProgressBar();
        }

        void Layer_DataLoaded(object sender, DataLoadedEventArgs e) {
            progressBar1.Value = 100;
            progressBar1.Visible = false;
            label1.Visible = false;
            requestsCounter = 0;
        }

        void UpdateProgressBar() {
            if (!progressBar1.Visible)
                progressBar1.Visible = true;
            if (!label1.Visible)
                label1.Visible = true;
            progressBar1.Value = (int)(100 * (requestsCounter - 1) / requestsCounter);
        }
    }
}

Form1.vb

Imports DevExpress.XtraMap
Imports System
Imports System.Windows.Forms

Namespace TilesLoaded
    Partial Public Class Form1
        Inherits Form

        Private requestsCounter As Integer = 0
        Private ReadOnly Property Layer() As ImageLayer
            Get
                Return CType(mapControl1.Layers(0), ImageLayer)
            End Get
        End Property

        Public Sub New()
            InitializeComponent()
            AddHandler Layer.RequestDataLoading, AddressOf Layer_RequestDataLoading
            AddHandler Layer.DataLoaded, AddressOf Layer_DataLoaded
        End Sub

        Private Sub Layer_RequestDataLoading(ByVal sender As Object, ByVal e As EventArgs)
            requestsCounter += 1
            UpdateProgressBar()
        End Sub

        Private Sub Layer_DataLoaded(ByVal sender As Object, ByVal e As DataLoadedEventArgs)
            progressBar1.Value = 100
            progressBar1.Visible = False
            label1.Visible = False
            requestsCounter = 0
        End Sub

        Private Sub UpdateProgressBar()
            If Not progressBar1.Visible Then
                progressBar1.Visible = True
            End If
            If Not label1.Visible Then
                label1.Visible = True
            End If
            progressBar1.Value = CInt(100 * (requestsCounter - 1) \ requestsCounter)
        End Sub
    End Class
End Namespace

Related GitHub Examples

The following code snippets (auto-collected from DevExpress Examples) contain references to the DataLoaded event.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

how-to-load-data-from-a-sql-geometry-data-source-t175898/CS/SqlGeometry/Form1.cs#L26

};
layer.DataLoaded += layer_DataLoaded;
mapControl1.Layers.Add(layer);

how-to-customize-coordinate-systems-of-a-map-and-data-source-t202055/CS/CoordinateSystems/Form1.cs#L21

    vectorLayer.Data = Adapter;
    vectorLayer.DataLoaded += DataLayer_DataLoaded;
}

how-to-implement-a-custom-clusterer-t312237/CS/CustomClustererSample/Form1.cs#L18

private void Form1_Load(object sender, EventArgs e) {
    VectorLayer.DataLoaded += (obj, args) => { map.ZoomToFitLayerItems(); };

how-to-load-cartesian-data-to-a-map-control-using-a-predefined-coordinate-converter-t208235/CS/BuildInCoordinateConverters/Form1.cs#L80

layer.ItemStyle.Fill = Color.FromArgb(40, 255, 128, 0);
layer.DataLoaded +=layer_DataLoaded;
mapControl1.Layers.Add(layer);

how-to-manually-provide-vector-items-from-wkt-t222638/CS/SqlGeometryItemStorage/Form1.cs#L22

VectorItemsLayer layer = new VectorItemsLayer() { Data = storage };
layer.DataLoaded += layer_DataLoaded;
mapControl1.Layers.Add(layer);

VB.NET

how-to-load-data-from-a-sql-geometry-data-source-t175898/VB/SqlGeometry/Form1.vb#L20

Dim layer As New VectorItemsLayer() With {.Data = adapter, .ShapeTitlesPattern = "{TextCol}"}
AddHandler layer.DataLoaded, AddressOf layer_DataLoaded
mapControl1.Layers.Add(layer)

how-to-automatically-load-a-cartesian-data-shapefile-onto-a-geo-map-t208696/VB/LoadGeoShapeData/Form1.vb#L39

layer.ItemStyle.Fill = Color.FromArgb(60, 255, 128, 0)
AddHandler layer.DataLoaded, AddressOf layer_DataLoaded

how-to-customize-coordinate-systems-of-a-map-and-data-source-t202055/VB/CoordinateSystems/Form1.vb#L23

    vectorLayer.Data = Adapter
    AddHandler vectorLayer.DataLoaded, AddressOf DataLayer_DataLoaded
End Sub

how-to-implement-a-custom-clusterer-t312237/VB/CustomClustererSample/Form1.vb#L28

Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    AddHandler VectorLayer.DataLoaded, Sub(obj, args)
        map.ZoomToFitLayerItems()

how-to-load-cartesian-data-to-a-map-control-using-a-predefined-coordinate-converter-t208235/VB/BuildInCoordinateConverters/Form1.vb#L59

layer.ItemStyle.Fill = Color.FromArgb(40, 255, 128, 0)
AddHandler layer.DataLoaded, AddressOf layer_DataLoaded
mapControl1.Layers.Add(layer)