Class
WebFileUploader
Description
WebFileUploader allows the user to choose files to be uploaded. You can then upload the files by calling the StartUpload method.
Properties
Name |
Type |
Read-Only |
Shared |
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✓ |
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✓ |
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✓ |
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✓ |
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Methods
Name |
Parameters |
Returns |
Shared |
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dragActionType As WebDragItem.DragActionTypes = WebDragItem.DragActionTypes.All |
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dragActionType As WebDragItem.DragActionTypes = WebDragItem.DragActionTypes.All |
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dragActionType As WebDragItem.DragActionTypes = WebDragItem.DragActionTypes.All |
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dragActionType As WebDragItem.DragActionTypes = WebDragItem.DragActionTypes.All |
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dragActionType As WebDragItem.DragActionTypes = WebDragItem.DragActionTypes.All |
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dragActionType As WebDragItem.DragActionTypes = WebDragItem.DragActionTypes.All |
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script As String |
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Events
Name |
Parameters |
Returns |
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hitItem As WebMenuItem |
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obj As WebDragItem, action As WebDragItem.DragActionTypes, x As Integer, y As Integer |
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fileName As String |
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error As RuntimeException |
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files() As WebUploadedFile |
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percent As Integer |
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fileCount As Integer |
Property descriptions
WebFileUploader.Caption
Caption As String
The caption for the button the user clicks to select a file. The default value is Select.
WebFileUploader.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 = menuThe 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
WebFileUploader.ControlID
ControlID As String
Identifies the control on a per session basis.
This property is read-only.
WebFileUploader.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
WebFileUploader.Filter
Filter As String
The MIME type of files that an be chosen for upload.
Separate MIME types with a comma.
This code in the Shown event handler for the WebFileUploader lets you choose PNG and JPG files:
Me.Filter = "image/png,image/jpeg"
WebFileUploader.HasFileNameField
HasFileNameField As Boolean
WebFileUploader.Indicator
Indicator As Indicators
The color scheme for the control.
WebFileUploader.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.
WebFileUploader.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).
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.
WebFileUploader.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.
WebFileUploader.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.
WebFileUploader.LockTop
LockTop As Boolean
Determines whether the top edge of the control should stay at a set distance from the top edge of the parent control, if there is one, or the owning web page.
WebFileUploader.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.
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.
WebFileUploader.MaximumBytes
MaximumBytes As Integer
The maximum number of bytes that can be uploaded, across all files selected, by a single call to StartUpload.
WebFileUploader.MaximumFileCount
MaximumFileCount As Integer
The maximum number of files that can be uploaded.
WebFileUploader.Name
Name As String
The name of the control.
This property is read-only.
WebFileUploader.Page
Page As WebPage
Identifies the web page that contains the control.
This property is read-only.
WebFileUploader.PanelIndex
PanelIndex As Integer
If the control has been placed on a WebTabPanel or WebPagePanel control, this is the panel (page/tab) that the control is on. If the control is not on a panel, it returns -1.
The first panel is numbered zero. If the control has been placed on a panel of a WebTabPanel or WebPagePanel control, it returns the panel number. If the control is not on a WebPagePanel or WebTabPanel, it returns -1. If you change the PanelIndex to a nonexistent panel, the control will disappear until you give it a PanelIndex value that corresponds to a panel that exists.
If you are looking to change the currently selected panel (page/tab), use SelectedPanelIndex.
This code displays the panel index of the control that is on the page.
MessageBox(Me.SelectedPanelIndex.ToString)
WebFileUploader.Parent
Parent As WebView
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.
WebFileUploader.TabIndex
TabIndex As Integer
The WebFileUploader'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
WebFileUploader.Tooltip
Tooltip As WebToolTip
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"
WebFileUploader.Top
Top As Integer
The top of the control in local coordinates relative to the web page.
WebFileUploader.UploadTimeout
UploadTimeout As Integer
The number of seconds that, once passed, will cause the UploadError event to be called.
The default is 0, which means "no timeout". Be aware that not having a timeout can result in out-of-memory issues for some web apps when uploading large (> 32MB) files.
WebFileUploader.Visible
Visible As Boolean
WebFileUploader.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
WebFileUploader.AcceptPictureDrop
AcceptPictureDrop(dragActionType As WebDragItem.DragActionTypes = WebDragItem.DragActionTypes.All)
Allows the control to accept a picture drop of a WebDragItem.
WebFileUploader.AcceptRawDataDrop
AcceptRawDataDrop(dragActionType As WebDragItem.DragActionTypes = WebDragItem.DragActionTypes.All)
Allows the control to accept a raw data drop of a WebDragItem.
WebFileUploader.AcceptTextDrop
AcceptTextDrop(dragActionType As WebDragItem.DragActionTypes = WebDragItem.DragActionTypes.All)
Allows the control to accept a picture drop of a WebDragItem.
WebFileUploader.AllowPictureDrag
AllowPictureDrag(dragActionType As WebDragItem.DragActionTypes = WebDragItem.DragActionTypes.All)
Allows the control to be dragged as a picture.
WebFileUploader.AllowRawDataDrag
AllowRawDataDrag(dragActionType As WebDragItem.DragActionTypes = WebDragItem.DragActionTypes.All)
Allows the control to be dragged as raw data.
WebFileUploader.AllowTextDrag
AllowTextDrag(dragActionType As WebDragItem.DragActionTypes = WebDragItem.DragActionTypes.All)
Allows the control to be dragged as text.
WebFileUploader.CancelUpload
CancelUpload
Cancels the upload.
WebFileUploader.Close
Close
Removes the control from the page.
WebFileUploader.CSSClasses
CSSClasses
Returns the instance of WebCSSClasses for this control allowing you to add CSS classes to and remove CSS classes from the control.
WebFileUploader.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();")
WebFileUploader.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)
WebFileUploader.RemoveAllFiles
RemoveAllFiles
Removes all files from the upload queue.
If an upload is already in progress, any files that had been added before the upload began will still be uploaded even if RemoveAllRows is called. This method is useful in cases where after an initial upload has begun and the user wants to prepare for another upload.
WebFileUploader.SetFocus
SetFocus
Sets the focus to the Control.
This code checks for a required value when a button is pressed:
If UserNameField.Text.IsEmpty Then MessageBox("Please enter your UserName.") UserNameField.SetFocus Return End If
WebFileUploader.StartUpload
StartUpload
Starts the upload process.
If you call this method when there are no files to upload or while a previous upload is still in progress, the UploadError event will fire.
WebFileUploader.Style
Style As WebStyle
Style(Assigns style As WebStyle)
WebFileUploader.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.MaximumValue = SalesData.RowCount For Each row As DatabaseRow in SalesData AnalyzeSales(row) ProgressBar1.Value = ProgressBar1.Value + 1 ProgressBar1.UpdateBrowser Next
Event descriptions
WebFileUploader.Closed
Closed
The control has been removed from the browser either because the page has closed or the control's Close method was called.
WebFileUploader.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 = menuThe 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
WebFileUploader.DropObject
DropObject(obj As WebDragItem, action As WebDragItem.DragActionTypes, x As Integer, y As Integer)
Called when a dragged item is over a control that can accept it. The dragged item is contained in obj and the type of drag is identified by action.
WebFileUploader.FileAdded
FileAdded(fileName As String, bytes As UInt64, MIMEType As String)
The file called Name has been added.
WebFileUploader.FileRemoved
FileRemoved(fileName As String)
The file passed has been removed from the upload queue.
WebFileUploader.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.
WebFileUploader.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.
WebFileUploader.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.
WebFileUploader.UploadAborted
UploadAborted
The uploaded was cancelled.
This occurs when, during an upload, the user closes the tab/window, closes the browser, the browser quits or crashes for some reason. Basically, this event occurs when the upload is abruptly aborted for any reason other than the app calling the CancelUpload method.
WebFileUploader.UploadError
UploadError(error As RuntimeException)
Called when an error occurs during the upload process.
WebFileUploader.UploadFinished
UploadFinished(files() As WebUploadedFile)
The upload has finished.
There will be a delay between the time files finish uploading and the UploadFinished event is called because the files must be processed once they are uploaded.
WebFileUploader.UploadProgressed
UploadProgressed(percent As Integer)
The uploaded has progressed to the percentage indicated.
There will be a delay between the time files finish uploading and the UploadFinished event is called because the files must be processed once they are uploaded.
WebFileUploader.UploadStarted
UploadStarted(fileCount As Integer)
The upload has started by the StartUpload method being called.
FileCount is the number of files that have been added to be uploaded.
Notes
There will be a delay between the time files finish uploading and the UploadFinished event is called because the files must be processed once they are uploaded.
WebFileUploader will always try to write files to the temporary folder on the server if possible to save memory. If that is not possible (because the temporary folder doesn't exist or is not writable), the files are copied into a MemoryBlock.
Sample code
To allow files to be uploaded by your web apps, add a FileUploader control to a web page. By itself, the user uses the Select button choose a file to be uploaded. Each time the user chooses a file, that file is added to the upload queue. If you wish to show the user a list of files they have chosen, add a WebListBox to the layout and then add files to that control when the FileAdded event handler is called. You'll likely also want to add a WebButton to the page for the user to click to start the upload. In it's Pressed event handler, call StartUpload:
FileUploader1.StartUpload
After the files have been uploaded, they will be in memory and the UploadFinished event handler is called. Here you can process the uploaded files and choose to do something with them. This code saves uploaded files to disk (you'll need to make sure your web app has the correct permissions on the server in order to write files):
Var outputFile As FolderItem
Var output As BinaryStream
For Each file As WebUploadedFile In files
Try
outputFile = New FolderItem(file.Name)
output = BinaryStream.Create(outputFile, True)
output.Write(file.Data)
output.Close
Catch e As IOException
Continue
End Try
Next
Compatibility
Project Types |
Web |
Operating Systems |
All |
See also
WebUIControl parent class; WebUploadedFile