Class
WebChart
Description
Displays data you provide in chart form of various types.
Properties
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Type |
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Shared |
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Methods
Name |
Parameters |
Returns |
Shared |
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dataset As WebChartDataset |
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index As Integer, Dataset As WebChartDataset |
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Datasets() As WebChartDataset |
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name As String |
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names() As String |
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index As Integer |
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script As String |
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index As Integer |
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index As Integer |
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index As Integer |
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Events
Name |
Parameters |
Returns |
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hitItem As WebMenuItem |
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options As JSONItem |
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dataset As WebChartDataset, index As Integer |
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Enumerations
WebChart.Modes
Modes
The various types of charts available.
Enum |
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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.Text
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.Text = "" 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.Text
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.Text = "Welcome!"
Else
Me.Text = "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.
See also
WebUIControl parent class; WebChartCircularDataset, WebChartDataset, WebChartLinearDataset and WebChartScatterDatapoint classes.