Class

WebContainer


Description

A WebContainer is a way to create a group of controls that are treated as a single control. A WebContainer is a great way to simplify complex web page layouts. In addition, with a WebContainer, you can create reusable controls to include on multiple web pages or on other web containers.

Methods

Name

Parameters

Returns

Shared

AddControl

Child As WebControl

Close

ControlAt

Index As Integer

WebControl

Controls

Iterable

EmbedWithin

View As WebView, Width As Integer, Height As Integer

ExecuteJavaScript

Script As String

GotoURL

Url As String, inNewWindow As Boolean = False

SetFocus

UpdateBrowser

Enumerations

WebContainer.ScrollDirections

ScrollDirections

The various directions that can be assigned for scrolling.

Enum

Description

None

The WebContainer cannot be scrolled.

Horizontal

The WebContainer can only be scrolled horizontally.

Vertical

The WebContainer can only be scrolled vertically.

Both

The WebContainer can be scrolled both horizontally and vertically.

Property descriptions


WebContainer.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

WebContainer.ControlID

ControlID As String

Identifies the control on a per session basis.

This property is read-only.


WebContainer.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

WebContainer.Height

Height As Integer

The height (in pixels) of the control.


WebContainer.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.


WebContainer.LastControlIndex

LastControlIndex As Integer

The index of the last WebControl on the WebView.


WebContainer.LayoutDirection

LayoutDirection As LayoutDirections

The direction in which WebContainer will flow when added at runtime to a layout whose LayoutType is set to Flex.


WebContainer.LayoutType

LayoutType As WebView.LayoutTypes

The type of layout dictates whether controls are positioned at fixed locations or can move to accommodate changes to the bounds of the WebView, in the latter case, only for WebContainer that are added at runtime to a layout whose type is set to Flex.


WebContainer.Left

Left As Integer

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


WebContainer.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.


WebContainer.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.


WebContainer.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.


WebContainer.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.


WebContainer.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.


WebContainer.Name

Name As String

The name of the control.

This property is read-only.


WebContainer.Page

Page As WebPage

Identifies the web page that contains the control.

This property is read-only.


WebContainer.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.


WebContainer.ScrollDirection

ScrollDirection As ScrollDirections

The direction or directions in which the user can scroll the WebContainer assuming that the bounds of the instance are smaller than bounds of the WebContainer itself.

This property is read-only.


WebContainer.Style

Style As WebStyle

The WebStyle for the control.

In the Pressed event of a WebButton, set the text to bold:

Var style As New WebStyle
style.Bold = True
Me.Style = style

WebContainer.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

WebContainer.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"

WebContainer.Top

Top As Integer

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


WebContainer.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

WebContainer.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


WebContainer.AddControl

AddControl(Child As WebControl)

Adds the passed Control to the WebView.

This code adds a WebTextField to the page:

Var tf As New WebTextField
tf.Left = 100
tf.Top = 50
tf.Enabled = True
Self.AddControl(tf)

WebContainer.Close

Close

This removes the control from the page, but only if the control is part of a Control Set or is a WebContainer. Otherwise it does not do anything.

In general, if you want to add or remove controls from pages, use a WebContainer.


WebContainer.ControlAt

ControlAt(Index As Integer) As WebControl

Returns the WebControl at the index passed.


WebContainer.Controls

Controls As Iterable

Allows you to iterate through the controls on the layout.


WebContainer.EmbedWithin

EmbedWithin(View As WebView, Width As Integer, Height As Integer)

Embeds the WebView in the current page without drawing the window frame, title bar, title bar widgets, grow handle, and so forth. Use this set of parameters with webpages whose LayoutType is Flex.

The Left and Top parameters determine the location of the top-left corner, relative to the containing page. The parameters Width and Height determine the size of the embedded view.

You can use EmbedWithin in to dynamically add controls to a page. Add the control (or controls) you want to add to a WebContainer and then use EmbedWithin to add the container to the page at runtime.

The locking properties of the WebContainer are not carried over when you use EmbedWithin. Instead, set these values accordingly before calling EmbedWithin. For example:

Var c As New MyContainer
c.LockLeft = True
c.LockTop = True
c.LockRight = True
c.EmbedWithin(Self, 0, 0, c.Width, c.Height)

This code adds a WebContainer, called LoginContainer, to a web page at runtime:

Var login As New LoginContainer
login.LockLeft = True
login.LockTop = True
login.EmbedWithin(Self, 0, 0, login.Width, login.Height)

WebContainer.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();")

WebContainer.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)

WebContainer.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

WebContainer.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


WebContainer.Closed

Closed

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


WebContainer.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

WebContainer.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.

The event is similar to the Window.Deactivate event in a desktop app.


WebContainer.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.


WebContainer.Overflowed

Overflowed

The area (in pixels) by which WebContainer have overflowed the bounds of a WebView whose LayoutType is set to WebView.LayoutTypes.


WebContainer.Resized

Resized

The WebView has been resized either because the user resized the browser window or the WebView was resized at runtime via code.


WebContainer.Scrolled

Scrolled

The WebContainer has been scrolled.


WebContainer.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

This class is useful for creating reusable sets of controls. Itʼs also useful for creating scrollable views. You can create a scrollable view by creating a WebContainer and then after placing it on a webpage or other WebContainer, make the WebContainer on the page smaller than it would normally appear. The ScrollDirection property controls which directions the user can scroll the WebContainer if any.

You can also use a WebContainer to center your page contents in the browser window. To do so, put all your controls on a WebContainer and then add the WebContainer to a WebPage. For the properties of the WebContainer, select LockVertical and LockHorizontal to ensure that the WebContainer always stays centered in the page displayed in the browser.

WebContainers can only contain controls that are subclasses of WebUIControl.

Sample code

This code adds a WebContainer, called LoginContainer, to a web page at runtime:

Var login As New LoginContainer
login.EmbedWithin(Self, 100, 100, login.Width, login.Height)

Compatibility

Web projects on all supported operating systems.

See also

WebView parent class; WebUIControl, WebPage, WebView