WebView
Introduction
WebView is a control that can be used to display a web page on a chart or an indicator output window.
WebView is based on Microsoft Edge WebView2. As a result, it is fully compatible with all modern web standards.
You can also execute JavaScript code on a page and get the results via WebView.
You can execute JS code on a page and get back the result with WebView.
Note
WebView only works on .NET 6 or later indicators and cBots.
How to Use WebView in cTrader
As an example, we will display the cTrader.com website inside a window and the main chart.
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46 | using cAlgo.API;
namespace cAlgo.Robots
{
[Indicator(AccessRights = AccessRights.None, IsOverlay = true)]
public class WebViewOnWindow : Indicator
{
private WebView _webView;
[Parameter("On Window?", DefaultValue = false)]
public bool OnWindow { get; set; }
protected override void Initialize()
{
_webView = new WebView
{
DefaultBackgroundColor = Color.Red
};
_webView.Loaded += OnWebViewLoaded;
if (OnWindow)
{
var window = new Window
{
Child = _webView
};
window.Show();
}
else
{
Chart.AddControl(_webView);
}
}
public override void Calculate(int index)
{
}
private void OnWebViewLoaded(WebViewLoadedEventArgs args)
{
_webView.NavigateAsync("https://ctrader.com/");
}
}
}
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After creating an instance of the below indicator, you will be able to navigate between various web pages on cTrader.com. In essence, your chosen output window will behave similarly to a web browser.
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187 | using cAlgo.API;
namespace cAlgo.Robots
{
[Robot(AccessRights = AccessRights.None)]
public class WebViewOnWindow : Robot
{
private WebView _webView;
private TextBox _addressTextBox;
private TextBox _scriptTextbox;
private Button _executeScriptButton;
protected override void OnStart()
{
var goBackButton = new Button
{
Text = "←",
Margin = 3
};
goBackButton.Click += OnGoBackButtonClick;
var goForwardButton = new Button
{
Text = "→",
Margin = 3
};
goForwardButton.Click += OnGoForwardButtonClick;
_addressTextBox = new TextBox
{
Text = "https://ctrader.com/",
Margin = 3,
Width = 150,
MinWidth = 150,
MaxWidth = 150
};
var goButton = new Button
{
Text = "→",
Margin = 3
};
goButton.Click += OnGoButtonClick;
var reloadButton = new Button
{
Text = "Reload",
Margin = 3
};
reloadButton.Click += OnReloadButtonClick;
var stopButton = new Button
{
Text = "x",
Margin = 3
};
stopButton.Click += OnStopButtonClick;
_scriptTextbox = new TextBox
{
Text = "alert('Hi');",
Margin = 3,
Width = 150,
MinWidth = 150,
MaxWidth = 150,
IsEnabled = false
};
_executeScriptButton = new Button
{
Text = "Execute Script",
Margin = 3,
IsEnabled = false
};
_executeScriptButton.Click += OnExecuteScriptButtonClick;
var addressBarPanel = new StackPanel
{
MaxHeight = 50,
VerticalAlignment = VerticalAlignment.Top,
BackgroundColor = Color.Black,
Orientation = Orientation.Horizontal
};
addressBarPanel.AddChild(goBackButton);
addressBarPanel.AddChild(goForwardButton);
addressBarPanel.AddChild(_addressTextBox);
addressBarPanel.AddChild(goButton);
addressBarPanel.AddChild(reloadButton);
addressBarPanel.AddChild(stopButton);
addressBarPanel.AddChild(_scriptTextbox);
addressBarPanel.AddChild(_executeScriptButton);
_webView = new WebView
{
DefaultBackgroundColor = Color.Red
};
_webView.NavigationCompleted += OnWebViewNavigationCompleted;
_webView.WebMessageReceived += OnWebViewWebMessageReceived;
_webView.Loaded += OnWebViewLoaded;
_webView.Unloaded += OnWebViewUnloaded;
var mainGrid = new Grid(2, 1);
mainGrid.Rows[0].SetHeightToAuto();
mainGrid.Rows[1].SetHeightInStars(1);
mainGrid.AddChild(addressBarPanel, 0, 0);
mainGrid.AddChild(_webView, 1, 0);
var window = new Window
{
Child = mainGrid
};
window.Show();
}
private void OnWebViewLoaded(WebViewLoadedEventArgs args)
{
Print($"Webview loaded, IsLoaded: {args.WebView.IsLoaded}");
_webView.NavigateAsync(_addressTextBox.Text);
}
private void OnWebViewUnloaded(WebViewUnloadedEventArgs args)
{
Print($"Webview unloaded, IsLoaded: {args.WebView.IsLoaded}");
}
private void OnStopButtonClick(ButtonClickEventArgs args)
{
_webView.StopAsync();
}
private void OnExecuteScriptButtonClick(ButtonClickEventArgs args)
{
var result = _webView.ExecuteScript(_scriptTextbox.Text);
Print($"IsSuccessful: {result.IsSuccessful} | Json: {result.Json}");
}
private void OnReloadButtonClick(ButtonClickEventArgs args)
{
_webView.ReloadAsync();
}
private void OnGoForwardButtonClick(ButtonClickEventArgs args)
{
_webView.GoForwardAsync();
}
private void OnGoBackButtonClick(ButtonClickEventArgs args)
{
_webView.GoBackAsync();
}
private void OnGoButtonClick(ButtonClickEventArgs args)
{
_webView.NavigateAsync(_addressTextBox.Text);
}
private void OnWebViewWebMessageReceived(WebViewWebMessageReceivedEventArgs args)
{
Print($"Source: {args.Source} | Message: {args.Message}");
}
private void OnWebViewNavigationCompleted(WebViewNavigationCompletedEventArgs args)
{
Print($"{args.HttpStatusCode} | {args.IsSuccessful} | {args.Url}");
_addressTextBox.Text = args.Url;
_scriptTextbox.IsEnabled = true;
_executeScriptButton.IsEnabled = true;
}
}
}
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Last update: March 23, 2023