Class

WebChart

Description

Displays data you provide in chart form of various types.

Events

Name

Parameters

Returns

Closed

ContextualMenuSelected

hitItem As WebMenuItem

Hidden

Opening

OverrideOptions

options As JSONItem

Pressed

dataset As WebChartDataset, index As Integer

Shown

Enumerations

WebChart.Modes

Modes

The various types of charts available.

Enum

Bar

Bubble

Doughnut

Line

Pie

PolarArea

Radar

Scatter

Property descriptions

WebChart.ContextualMenu

ContextualMenu As WebMenuItem

If you assign a WebMenuItem to the control, it will be displayed when the user right-clicks the control.

On a WebPage, you can disable/remove the default contextual menu by an empty WebMenuItem class object to this property.

This code populates a contextual menu in the Shown event of the control.

Var menu As New WebMenuItem

menu.AddMenuItem("One")
menu.AddMenuItem("Two")
menu.AddMenuItem("Three")
Me.ContextualMenu = menu

The menu selection is then handled by the ContextualMenuSelected event when the user right-clicks on the control. For example, it can be of the form:

Select case hitItem.Value
Case "One"
  MessageBox("One")
Case "Two"
  MessageBox("Two")
Case "Three"
  MessageBox("Three")
End Select

WebChart.ControlID

ControlID As String

Identifies the control on a per session basis.

This property is read-only.

WebChart.DatasetCount

DatasetCount As Integer

{

This property is read-only.

WebChart.Enabled

Enabled As Boolean

When True the WebControl is drawn enabled and responds to user action. When False, the control appears as disabled and does not respond to user actions.

In the case of WebTimer, when set to False this disables and stops the WebTimer. When set to True, it starts the WebTimer.

Disable a button when a check box value changes:

If AllowSaveCheckBox.Value Then
  SaveButton.Enabled = True
Else
  AllowSaveButton.Enabled = False
End If

WebChart.HasAnimation

HasAnimation As Boolean

If True, changes to chart data will result in animated updates to the chart.

WebChart.HasLegend

HasLegend As Boolean

If True, the chart's legend will be displayed.

WebChart.Height

Height As Integer

The height (in pixels) of the control.

WebChart.Indicator

Indicator As Indicators

The color scheme for the control.

When a WebButton's Default or Cancel properties are True, the Indictor property is ignored as Default and Cancel buttons have a default indicator.

WebChart.Left

Left As Integer

The position of the left side of the WebUIControl in pixels, relative to the web page.

WebChart.LockBottom

LockBottom As Boolean

Determines whether the bottom edge of the control should stay at a set distance from the bottom edge of the parent control, if there is one, or the owning web page.

This property is read-only.

WebChart.LockHorizontal

LockHorizontal As Boolean

LockHorizontal overrides LockLeft and LockRight. It allows you to proportionally lock a control's position to the center of its parent control (or web page).

This property is read-only.

For example, if you place a control in the center of the page and sets both LockHorizontal and LockVertical, the control will stay in the center of the page.

WebChart.LockLeft

LockLeft As Boolean

Determines whether the left edge of the control should stay at a set distance from the left edge of the parent control, if there is one, or the owning web page.

This property is read-only.

WebChart.LockRight

LockRight As Boolean

Determines whether the right edge of the control should stay at a set distance from the right edge of the parent control, if there is one, or the owning web page.

This property is read-only.

WebChart.LockVertical

LockVertical As Boolean

LockVertical overrides LockTop and LockBottom. It allows you to proportionally lock a control's position to keep it centered within the parent control or web page.

This property is read-only.

For example, if you place a control in the center of the page, and sets both LockHorizontal and LockVertical, the control will stay in the center of the page.

WebChart.Mode

Mode As Modes

Indicates the type of chart the control is currently displaying.

This property is read-only.

Labels are required for a Bar chart to draw.

This example checks the mode of the chart:

If Chart1.Mode = WebChart.Modes.Bar then
  Chart1.Title = "Sales Bar Chart"
End If

WebChart.Name

Name As String

The name of the control.

This property is read-only.

WebChart.Page

Page As WebPage

Identifies the web page that contains the control.

This property is read-only.

WebChart.Parent

Parent As WebControl

Used to get the control's parent control or page. If the parent control is a WebContainer, then it returns the WebContainer. If it is on a WebPage, it returns the WebPage.

This property is read-only.

WebChart.TabIndex

TabIndex As Integer

The WebUIControl's control's position in the Tab Order. The control with a TabIndex of 0 is the first WebUIControl to get the focus when the page opens in the browser.

This example sets the control's TabIndex.

Me.TabIndex = 2

WebChart.Title

Title As String

The title of the chart.

WebChart.Tooltip

Tooltip As String

Text of a message displayed as a tooltip.

The tip is displayed when the user places the mouse on the control and leaves it there.

This code in the Shown event of a Button sets the tooltip:

Me.Tooltip = "Save changes"

WebChart.Top

Top As Integer

The top of the control in local coordinates relative to the web page.

WebChart.Visible

Visible As Boolean

If True, the control is drawn. If False, it's not.

Hide a control based on a checkbox setting:

If ShowEmailCheckbox.Value Then
  EmailField.Visible = True
Else
  EmailField.Visible = False
End If

WebChart.Width

Width As Integer

The width (in pixels) of the web control.

This code in the Shown event handler increases the size of the control:

Me.Width = Me.Width + 50

Method descriptions

WebChart.AddDataset

AddDataset(dataset As WebChartDataset)

Adds the dataset to the chart.

WebChart.AddDatasetAt

AddDatasetAt(index As Integer, dataset As WebChartDataset)

Adds the dataset to the chart at the index passed.

WebChart.AddDatasets

AddDatasets(datasets() As WebChartDataset)

Adds the array of datasets to the chart.

WebChart.AddLabel

AddLabel(name As String)

Adds the label to the chart.

WebChart.AddLabelAt

AddLabelAt(index As String, name As String)

Adds the label to the chart at the index passed.

WebChart.AddLabels

AddLabels(names() As String)

Adds the array of labels to the chart.

WebChart.Close

Close

Closes the chart?.

WebChart.DatasetAt

DatasetAt(index As Integer) As WebChartDataset

Returns the WebChartDataset at the index passed.

WebChart.ExecuteJavaScript

ExecuteJavaScript(script As String)

Executes the JavaScript passed. The JavaScript passed can call a JavaScript function in a WebPageSource control.

The Xojo web framework uses EcmaScript 6 which is more strict than previous versions of JavaScript. For more details, see the EcmaScript 6 documentation.

This code in the Pressed event of a Button displays an alert using JavaScript:

Me.ExecuteJavaScript("alert('Hello!');")

This code will select the text in a WebTextField (or WebTextArea):

WebTextField1.ExecuteJavascript("document.getElementById('" + _
  WebTextField1.ControlID + "_inner').select();")

WebChart.GotoURL

GotoURL(URL As String, inNewWindow As Boolean = False)

Opens the passed URL in place of the current web page or downloads a file. If InNewWindow is True, the browser is asked to open the URL in a new window.

If the browser has popup windows disabled and InNewWindow is True, the method silently fails and the page is not shown.

If InNewWindow is False, the running web app is replaced with the specified URL. If you want to display an external web site within your web app, use the WebHTMLViewer control.

Display a web site in a new popup window:

Me.GotoURL("http://www.wikipedia.org", True)

WebChart.LabelAt

LabelAt(index As Integer) As WebChartDataset

Returns the label at the index passed.

WebChart.RemoveAllDatasets

RemoveAllDatasets

Removes all datasets from the chart.

WebChart.RemoveAllLabels

RemoveAllLabels

Removes all labels from the chart.

WebChart.RemoveDatasetAt

RemoveDatasetAt(index As Integer)

Removes the WebChartDataset at the index passed.

WebChart.RemoveLabelAt

RemoveLabelAt(index As Integer)

Removes the label at the index passed.

WebChart.SetFocus

SetFocus

Sets the focus to the Control.

This code checks for a required value when a button is pressed:

If UserNameField.Value = "" Then
  MessageBox("Please enter your UserName.")
  UserNameField.SetFocus
  Return
End If

WebChart.Style

Style As WebStyle

Returns the WebStyle of the chart.

Style(Assigns`</api/language/assigns> style As :doc:`WebStyle</api/user_interface/web/webstyle>)

Returns the WebStyle of the chart.

WebChart.UpdateBrowser

UpdateBrowser

Forces the current values of the control to be sent to the browser.

This method is useful when you are computing values in a loop and wish to update the browser immediately rather than wait until the current method ends.

This code iterates through a RowSet of database rows, updates a ProgressBar and then forces the updated ProgressBar to be sent to the browser via UpdateBrowser.

ProgressBar1.Maximum = SalesData.RowCount
For Each row As DatabaseRow in SalesData
 AnalyzeSales(row)
 ProgressBar1.Value = ProgressBar1.Value + 1
 ProgressBar1.UpdateBrowser
Next

Event descriptions

WebChart.Closed

Closed

The control has been removed from the browser either because the page has closed or the control's Close method was called.

WebChart.ContextualMenuSelected

ContextualMenuSelected(hitItem As WebMenuItem)

Called when a contextual menu item is selected. This selected item is contained in hitItem.

This code populates a contextual menu in the Opening event of a WebToolbar:

Var menu As New WebMenuItem

menu.AddMenuItem("One")
menu.AddMenuItem("Two")
menu.AddMenuItem("Three")
Me.ContextualMenu = menu

The menu selection is then handled by the ContextualMenuSelected event when the user right-clicks on the control. For example, it can be of the form:

Select case hitItem.Value
Case "One"
  MessageBox("One")
Case "Two"
  MessageBox("Two")
Case "Three"
  MessageBox("Three")
End Select

WebChart.Hidden

Hidden

The control is about to become no longer visible. This could be because the page is being closed, is being replaced as the foreground page by another page or because the control or a parent control's Visible property has been set to False.

Note

This event is equivalent to the DesktopWindow.Deactivated event in a desktop app.

WebChart.Opening

Opening

The control has been created and the page is opening but has not been sent to the browser yet.

The Opening event handler can be used to initialize non-visual properties and settings for controls.

In most cases, you should use the Shown event to initialize controls.

WebChart.OverrideOptions

OverrideOptions(options As JSONItem)

Allows you to override the built-in features of WebChart by modifying the Options parameter passed.

WebChart is based upon ChartJS. See the ChartJS website for details on the format of the data in the Options parameter.

WebChart.Pressed

Pressed(dataset As WebChartDataset, index As Integer)

The user pressed on a part of the chart that represents data.

WebChart.Shown

Shown

The control has appeared on the currently displayed page. This could be because its parent page just finished loading, its parent page has come to the foreground or the control is now visible having been previously invisible because it or its parent control's Visible property has been set to True.

Use the Shown event for initializing your controls or doing anything that would interact with other controls or user interface elements on the web page instead of the Opening event.

Note

This event is the web equivalent to the DesktopWindow.Activated event.

This code in the Shown event of a WebListBox adds 2 rows with 3 columns:

Me.RemoveAllRows
Me.AddRow("Row 1", "Bob", "Roberts")
Me.AddRow("Row 2", "Barb", "Reynolds")

This example sets the text of a label:

If Session.LoggedIn Then
  Me.Value = "Welcome!"
Else
  Me.Value = "Welcome, " + Session.UserName
End If

Notes

If you wish to set the background color of the chart, do so via the Style property.

Compatibility

Web projects on all supported operating systems.