ImageLayer.RequestDataLoading Event

Occurs when a request data download has begun.

Namespace: DevExpress.XtraMap

Assembly: DevExpress.XtraMap.v24.1.dll

NuGet Package: DevExpress.Win.Map

Declaration

C#

public event EventHandler RequestDataLoading

VB.NET

Public Event RequestDataLoading As EventHandler

Event Data

The RequestDataLoading event's data class is EventArgs.

Example

This example demonstrates how to monitor the service request state.

To do this, handle the ImageLayer.RequestDataLoading event. Specify the wait form which will be shown when data is loading. Handle the LayerBase.DataLoaded event to determine the state of the wait form after the map data is obtained.

Form1.cs

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


namespace RequestDataLoadingExample {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e) {
            ImageLayer layer = new ImageLayer();
            mapControl1.Layers.Add(layer);
            BingMapDataProvider provider = new BingMapDataProvider();
            provider.BingKey = "YOUR_BING_KEY";
            layer.DataProvider = provider;
            layer.RequestDataLoading += OnRequestDataLoading;
            layer.DataLoaded += OnDataLoaded;
        }
        void OnRequestDataLoading(object sender, EventArgs e) {
            Cursor.Current = Cursors.WaitCursor;
            if (!splashScreenManager1.IsSplashFormVisible)
                splashScreenManager1.ShowWaitForm();
        }
        void OnDataLoaded(object sender, DataLoadedEventArgs e) {
            Cursor.Current = Cursors.Default;
            splashScreenManager1.CloseWaitForm();
        }

    }
}

Form1.vb

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


Namespace RequestDataLoadingExample
    Partial Public Class Form1
        Inherits Form

        Public Sub New()
            InitializeComponent()
        End Sub
        Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
            Dim layer As New ImageLayer()
            mapControl1.Layers.Add(layer)
            Dim provider As New BingMapDataProvider()
            provider.BingKey = "YOUR_BING_KEY"
            layer.DataProvider = provider
            AddHandler layer.RequestDataLoading, AddressOf OnRequestDataLoading
            AddHandler layer.DataLoaded, AddressOf OnDataLoaded
        End Sub
        Private Sub OnRequestDataLoading(ByVal sender As Object, ByVal e As EventArgs)
            Cursor.Current = Cursors.WaitCursor
            If Not splashScreenManager1.IsSplashFormVisible Then
                splashScreenManager1.ShowWaitForm()
            End If
        End Sub
        Private Sub OnDataLoaded(ByVal sender As Object, ByVal e As DataLoadedEventArgs)
            Cursor.Current = Cursors.Default
            splashScreenManager1.CloseWaitForm()
        End Sub

    End Class
End Namespace

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the RequestDataLoading 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#

winforms-map-show-the-progress-of-loading-image-tiles/CS/TilesLoaded/Form1.cs#L12

InitializeComponent();
Layer.RequestDataLoading += Layer_RequestDataLoading;
Layer.DataLoaded += Layer_DataLoaded;

VB.NET

winforms-map-show-the-progress-of-loading-image-tiles/VB/TilesLoaded/Form1.vb#L20

InitializeComponent()
AddHandler Layer.RequestDataLoading, AddressOf Layer_RequestDataLoading
AddHandler Layer.DataLoaded, AddressOf Layer_DataLoaded