cWebView2Host Events Reference

📋 Events Overview

cWebView2Host provides 40+ events covering the entire WebView2 lifecycle. To use events, declare the variable with WithEvents:

Dim WithEvents wv As cWebView2Host

Event Category Index

Category	Event	Trigger Timing
Lifecycle	Create	WebView2 control creation completed
	Ready	WebView2 control initialization completed, control ready
	Error	Error during creation or runtime
Navigation	NavigationStarting	Navigation starting (cancelable)
	NavigationComplete	Navigation completed
	SourceChanged	URL changed
	DocumentTitleChanged	Document title changed
	DOMContentLoaded	DOM loading completed
Permission/Dialog	PermissionRequested	Page requests permission
	ScriptDialogOpening	Script dialog appearing (alert/confirm/prompt)
	AcceleratorKeyPressed	Accelerator key pressed
	NewWindowRequested	Page requests opening new window
Resources	WebResourceRequested	Web resource request intercepted
	ProcessFailed	Browser process failed
	DownloadStarting	Download about to start
Scripting	JsAsyncResult	Async script execution completed
	JsMessage	JS postMessage received
	DevToolsProtocolResponse	CDP async response
Host Mouse	HostMouseDown	Mouse down in host area
	HostMouseUp	Mouse up in host area
	HostMouseDblClick	Mouse double-click in host area
	HostMouseMove	Mouse move in host area
	HostMouseWheel	Mouse wheel in host area
	HostContextMenu	Context menu in host area
Host Keyboard	HostKeyDown	Key down in host area
	HostKeyUp	Key up in host area
	HostKeyPress	Key press in host area
	HostFocus	WebView2 gained focus
	HostBlur	WebView2 lost focus
	HostResize	Host window size changed
User Mouse	UserMouseDown	Mouse down in content area
	UserMouseUp	Mouse up in content area
	UserMouseMove	Mouse move in content area
	UserMouseWheel	Mouse wheel in content area
	UserContextMenu	Context menu in content area
	UserDblClick	Mouse double-click in content area
Suspend	SuspendCompleted	Suspend succeeded
	SuspendFailed	Suspend failed
PDF	PrintToPdfCompleted	PDF print succeeded
	PrintToPdfFailed	PDF print failed
Business	OnGetCookiesFull	Async cookie retrieval completed

🔄 Lifecycle Events

Create

WebView2 control creation completed, but navigation has not yet started.

Private Sub wv_Create()

Trigger Timing: After WebView2 Environment and Controller are successfully created.

Purpose: This is the correct timing to configure EnvironmentOptions and Security, since the environment is created but navigation has not yet started.

Example:

Private Sub wv_Create()
    ' Configure user data directory
    wv.EnvironmentOptions.UserDataFolder = App.Path & "\UserDir\account-001"
    ' Configure security options
    wv.Security.CertificateErrorAction = CEA_AlwaysAllow
End Sub

Ready

WebView2 control initialization completed, control fully ready.

Private Sub wv_Ready()

Trigger Timing: Fires once after the WebView2 control initialization completes. Does not trigger again.

Purpose: Safely perform initialization operations such as binding events, registering data bindings, injecting scripts, etc.

Example:

Private Sub wv_Ready()
    Me.Caption = wv.DocumentTitle
    
    ' Set up data bindings
    wv.BindData "name", "#name-input", "value"
    wv.BindUI Me, "OnNameInput", "#name-input", EventName:="input"
    wv.SetData "name", "Default value"
    
    ' Inject script
    wv.AddScriptToExecuteOnDocumentCreated "window.__appReady = true;"
End Sub

Error

Error during creation or runtime.

Private Sub wv_Error(ByVal Description As String)

Parameters:

Description - Error description message

NavigationStarting

Navigation is about to start — can be canceled via the Cancel parameter.

Private Sub wv_NavigationStarting(ByVal Uri As String, ByVal IsUserInitiated As Boolean, ByRef Cancel As Boolean)

Parameters:

Uri - Target URL
IsUserInitiated - Whether triggered by user action (e.g., clicking a link)
Cancel - Set to True to cancel navigation

Example:

Private Sub wv_NavigationStarting(ByVal Uri As String, ByVal IsUserInitiated As Boolean, ByRef Cancel As Boolean)
    ' Block navigation to specific domain
    If InStr(UCase(Uri), "ADS.EXAMPLE.COM") > 0 Then
        Cancel = True
    End If
End Sub

NavigationComplete

Navigation completed.

Private Sub wv_NavigationComplete(ByVal IsSuccess As Boolean, ByVal ErrorStatus As wv2ErrorStatus)

Parameters:

IsSuccess - Whether navigation succeeded
ErrorStatus - Error status code (0 on success)

SourceChanged

URL changed.

Private Sub wv_SourceChanged(ByVal IsNewDocument As Boolean)

Parameters:

IsNewDocument - Whether this is a new document (vs. same-page navigation)

DocumentTitleChanged

Document title changed.

Private Sub wv_DocumentTitleChanged()

Example:

Private Sub wv_DocumentTitleChanged()
    Me.Caption = wv.DocumentTitle
End Sub

DOMContentLoaded

DOM content loading completed (earlier than NavigationComplete).

Private Sub wv_DOMContentLoaded()

Purpose: Perform operations when DOM is ready but resources (images, etc.) have not fully loaded.

🔐 Permission/Dialog Events

PermissionRequested

Page requests permission (geolocation, camera, microphone, etc.).

Private Sub wv_PermissionRequested(ByVal Uri As String, ByVal PermissionKind As wv2PermissionKind, ByVal IsUserInitiated As Boolean, ByRef State As wv2PermissionState)

Parameters:

Uri - URL of the page requesting permission
PermissionKind - Permission type enum
IsUserInitiated - Whether triggered by user action
State - Permission state, can be set to wv2PermissionState_Allow or wv2PermissionState_Deny

Example:

Private Sub wv_PermissionRequested(ByVal Uri As String, ByVal PermissionKind As wv2PermissionKind, ByVal IsUserInitiated As Boolean, ByRef State As wv2PermissionState)
    ' Auto-allow geolocation from trusted domains
    If PermissionKind = wv2PermissionKind_Geolocation And InStr(Uri, "myapp.com") > 0 Then
        State = wv2PermissionState_Allow
    Else
        State = wv2PermissionState_Deny
    End If
End Sub

ScriptDialogOpening

JavaScript dialog about to appear (alert / confirm / prompt / beforeunload).

Private Sub wv_ScriptDialogOpening(ByVal Kind As wv2ScriptDialogKind, ByVal Message As String, ByRef Accept As Boolean)

Parameters:

Kind - Dialog type
Message - Dialog message content
Accept - Set to True to accept the dialog (equivalent to clicking OK), False to cancel

Note: Can be used to customize dialog appearance, replacing the browser's default dialogs.

AcceleratorKeyPressed

Accelerator key pressed event.

Private Sub wv_AcceleratorKeyPressed(ByVal KeyEventKind As wv2KeyEventKind, ByVal VirtualKey As Long, ByRef Handled As Boolean)

Parameters:

KeyEventKind - Key event type (KeyDown/Up/SystemKeyDown/Up)
VirtualKey - Virtual key code
Handled - Set to True to prevent WebView2 from handling this key

Example:

Private Sub wv_AcceleratorKeyPressed(ByVal KeyEventKind As wv2KeyEventKind, ByVal VirtualKey As Long, ByRef Handled As Boolean)
    ' Intercept F5 refresh
    If VirtualKey = vbKeyF5 Then
        Handled = True
        ' Custom refresh logic
    End If
End Sub

NewWindowRequested

Page requests opening a new window (target="_blank" or window.open).

Private Sub wv_NewWindowRequested(ByVal Uri As String, ByVal IsUserInitiated As Boolean, ByRef Handled As Boolean)

Parameters:

Uri - Target URL of the new window
IsUserInitiated - Whether triggered by user action
Handled - Set to True to prevent opening a new window

Example:

Private Sub wv_NewWindowRequested(ByVal Uri As String, ByVal IsUserInitiated As Boolean, ByRef Handled As Boolean)
    ' Navigate in current window (block popup)
    Handled = True
    wv.Navigate Uri
End Sub

📦 Resource Events

WebResourceRequested

Web resource request intercepted by AddWebResourceRequestedFilter.

Private Sub wv_WebResourceRequested(ByVal Request As WebView2Request, ByVal Response As WebView2Response)

Parameters:

Request - Request object, can read Method, Uri, Headers, Content
Response - Response object; after setting values, WebView2 uses this response instead of the actual network request

Note: Must call AddWebResourceRequestedFilter to register a filter before this event will fire.

ProcessFailed

Browser process failed.

Private Sub wv_ProcessFailed(ByVal FailedKind As wv2ProcessFailedKind)

Parameters:

FailedKind - Process failure type enum

DownloadStarting

Download about to start.

Private Sub wv_DownloadStarting(ByVal ResultFilePath As String, ByRef Cancel As Boolean, ByRef Handled As Boolean)

Parameters:

ResultFilePath - Download file path
Cancel - Set to True to cancel download
Handled - Set to True to indicate handled

⚡ Script Events

JsAsyncResult

Async script execution completed (callback for ExecuteScript / JsRunAsync).

Private Sub wv_JsAsyncResult(ByVal Token As Long, ByVal Result As String, ByVal ErrorCode As Long)

Parameters:

Token - Token specified at call time
Result - JSON string of JS execution result
ErrorCode - Error code, 0 indicates success

Example:

wv.ExecuteScript "document.title", 1001
wv.JsRunAsync "fetch('/api').then(r=>r.json())"  ' Returns auto token

Private Sub wv_JsAsyncResult(ByVal Token As Long, ByVal Result As String, ByVal ErrorCode As Long)
    If ErrorCode = 0 Then
        Debug.Print "Token " & Token & " => " & Result
    End If
End Sub

JsMessage

Message received from JS via window.chrome.webview.postMessage().

Private Sub wv_JsMessage(ByVal Message As String)

Parameters:

Message - Message string sent from JS

Example:

' VB6 side
Private Sub wv_JsMessage(ByVal Message As String)
    Debug.Print "JS message: " & Message
End Sub

' JS side
window.chrome.webview.postMessage("Hello from JS");

DevToolsProtocolResponse

CDP async call response.

Private Sub wv_DevToolsProtocolResponse(ByVal CustomEventId As Variant, ByVal JsonResponse As String)

Parameters:

CustomEventId - Custom event ID specified at call time
JsonResponse - JSON string of CDP response

Example:

wv.CallDevToolsProtocolMethod "Page.captureScreenshot", "{}", "screenshot"

Private Sub wv_DevToolsProtocolResponse(ByVal CustomEventId As Variant, ByVal JsonResponse As String)
    If CustomEventId = "screenshot" Then
        ' Process screenshot data
    End If
End Sub

🖱️ Host Mouse Events

Host mouse events are captured by subclassing the host window and reflect mouse operations in the host window area (not the WebView2 content area).

HostMouseDown

Private Sub wv_HostMouseDown(ByVal Button As wv2MouseButton, ByVal Shift As wv2ShiftState, ByVal X As Long, ByVal Y As Long)

Parameters:

Button - Mouse button (1=Left, 2=Right, 4=Middle, bitmask)
Shift - Modifier key state (1=Shift, 2=Ctrl, 4=Alt, bitmask)
X, Y - Mouse coordinates (client area pixels)

HostMouseUp

Private Sub wv_HostMouseUp(ByVal Button As wv2MouseButton, ByVal Shift As wv2ShiftState, ByVal X As Long, ByVal Y As Long)

HostMouseDblClick

Private Sub wv_HostMouseDblClick(ByVal Button As wv2MouseButton, ByVal Shift As wv2ShiftState, ByVal X As Long, ByVal Y As Long)

HostMouseMove

Private Sub wv_HostMouseMove(ByVal Button As wv2MouseButton, ByVal Shift As wv2ShiftState, ByVal X As Long, ByVal Y As Long)

Note: Requires EnableMouseMoveEvents = True to fire; disabled by default to avoid performance issues.

HostMouseWheel

Private Sub wv_HostMouseWheel(ByVal Delta As Long, ByVal Shift As wv2ShiftState, ByVal X As Long, ByVal Y As Long)

Parameters:

Delta - Wheel delta, positive for scroll up, negative for scroll down

HostContextMenu

Private Sub wv_HostContextMenu(ByVal X As Long, ByVal Y As Long)

⌨️ Host Keyboard Events

HostKeyDown / HostKeyUp / HostKeyPress

Private Sub wv_HostKeyDown(ByVal KeyCode As Long, ByVal Shift As wv2ShiftState)
Private Sub wv_HostKeyUp(ByVal KeyCode As Long, ByVal Shift As wv2ShiftState)
Private Sub wv_HostKeyPress(ByVal KeyAscii As Long)

HostFocus / HostBlur

Private Sub wv_HostFocus()
Private Sub wv_HostBlur()

HostResize

Private Sub wv_HostResize()

Note: Fires when host window size changes; can call wv.Resize() here to manually adjust WebView2 size (e.g., when using MessageWindowAdapter).

🎯 User Mouse Events

User mouse events are synchronously called back from the WebView2 content area to the host via the mouseProxy COM proxy. Requires EnableUserMouseEvents = True.

UserMouseDown / UserMouseUp

Private Sub wv_UserMouseDown(ByVal Button As Long, ByVal X As Long, ByVal Y As Long, ByVal Shift As Long, ByRef Handled As Boolean)
Private Sub wv_UserMouseUp(ByVal Button As Long, ByVal X As Long, ByVal Y As Long, ByVal Shift As Long, ByRef Handled As Boolean)

Parameters:

Button - Mouse button (1=Left, 2=Right, 4=Middle)
X, Y - Pixel coordinates within content area
Shift - Modifier key state
Handled - Set to True to prevent event from propagating to WebView2

UserMouseMove

Private Sub wv_UserMouseMove(ByVal X As Long, ByVal Y As Long, ByVal Shift As Long, ByRef Handled As Boolean)

Note: Requires additional EnableUserMouseMove = True; disabled by default to avoid performance issues.

UserMouseWheel

Private Sub wv_UserMouseWheel(ByVal Delta As Long, ByVal X As Long, ByVal Y As Long, ByVal Shift As Long, ByRef Handled As Boolean)

UserContextMenu

Private Sub wv_UserContextMenu(ByVal X As Long, ByVal Y As Long, ByRef Handled As Boolean)

UserDblClick

Private Sub wv_UserDblClick(ByVal Button As Long, ByVal X As Long, ByVal Y As Long, ByVal Shift As Long, ByRef Handled As Boolean)

🔌 Suspend/PDF/Business Events

SuspendCompleted / SuspendFailed

Private Sub wv_SuspendCompleted()
Private Sub wv_SuspendFailed(ByVal ErrorCode As Long)

PrintToPdfCompleted / PrintToPdfFailed

Private Sub wv_PrintToPdfCompleted(ByVal ResultFilePath As String)
Private Sub wv_PrintToPdfFailed(ByVal ErrorCode As Long)

OnGetCookiesFull

Async full cookie retrieval completed.

Private Sub wv_OnGetCookiesFull(ByVal CookiesJson As String)

Trigger Timing: When async result returns after calling wv.Cookies.GetCookiesFullAsync().

📐 Enum Reference

wv2MouseButton

Constant	Value	Description
Left	1	Left mouse button
Right	2	Right mouse button
Middle	4	Middle mouse button

Bitmask combination, can include multiple values simultaneously.

wv2ShiftState

Constant	Value	Description
Shift	1	Shift key
Ctrl	2	Ctrl key
Alt	4	Alt key

Bitmask combination. Detection method: If Shift And 2 Then ' Ctrl is pressed

wv2ScriptDialogKind

Constant	Description
Alert	alert() dialog
Confirm	confirm() dialog
Prompt	prompt() dialog
BeforeUnload	beforeunload dialog

wv2PermissionKind

Constant	Description
Unknown	Unknown permission
Microphone	Microphone
Camera	Camera
Geolocation	Geolocation
Notifications	Notifications
OtherSensors	Other sensors
ClipboardRead	Clipboard read

wv2PermissionState

Constant	Description
Default	Default (browser decides)
Allow	Allow
Deny	Deny

EnumCertificateErrorAction

Constant	Value	Description
CEA_Default	0	Default behavior (deny)
CEA_Cancel	1	Cancel request
CEA_AlwaysAllow	2	Always allow (injects command-line argument)

Last Updated: 2026-06-24

cWebView2Host Events Reference ​

📋 Events Overview ​

Event Category Index ​

🔄 Lifecycle Events ​

Create ​

Ready ​

Error ​

🧭 Navigation Events ​

NavigationStarting ​

NavigationComplete ​

SourceChanged ​

DocumentTitleChanged ​

DOMContentLoaded ​

🔐 Permission/Dialog Events ​

PermissionRequested ​

ScriptDialogOpening ​

AcceleratorKeyPressed ​

NewWindowRequested ​

📦 Resource Events ​

WebResourceRequested ​

ProcessFailed ​

DownloadStarting ​

⚡ Script Events ​

JsAsyncResult ​

JsMessage ​

DevToolsProtocolResponse ​

🖱️ Host Mouse Events ​

HostMouseDown ​

HostMouseUp ​

HostMouseDblClick ​

HostMouseMove ​

HostMouseWheel ​

HostContextMenu ​

⌨️ Host Keyboard Events ​

HostKeyDown / HostKeyUp / HostKeyPress ​

HostFocus / HostBlur ​

HostResize ​

🎯 User Mouse Events ​

UserMouseDown / UserMouseUp ​

UserMouseMove ​

UserMouseWheel ​

UserContextMenu ​

UserDblClick ​

🔌 Suspend/PDF/Business Events ​

SuspendCompleted / SuspendFailed ​

PrintToPdfCompleted / PrintToPdfFailed ​

OnGetCookiesFull ​

📐 Enum Reference ​

wv2MouseButton ​

wv2ShiftState ​

wv2ScriptDialogKind ​

wv2PermissionKind ​

wv2PermissionState ​

EnumCertificateErrorAction ​

cWebView2Host Events Reference

📋 Events Overview

Event Category Index

🔄 Lifecycle Events

Create

Ready

Error

🧭 Navigation Events

NavigationStarting

NavigationComplete

SourceChanged

DocumentTitleChanged

DOMContentLoaded

🔐 Permission/Dialog Events

PermissionRequested

ScriptDialogOpening

AcceleratorKeyPressed

NewWindowRequested

📦 Resource Events

WebResourceRequested

ProcessFailed

DownloadStarting

⚡ Script Events

JsAsyncResult

JsMessage

DevToolsProtocolResponse

🖱️ Host Mouse Events

HostMouseDown

HostMouseUp

HostMouseDblClick

HostMouseMove

HostMouseWheel

HostContextMenu

⌨️ Host Keyboard Events

HostKeyDown / HostKeyUp / HostKeyPress

HostFocus / HostBlur

HostResize

🎯 User Mouse Events

UserMouseDown / UserMouseUp

UserMouseMove

UserMouseWheel

UserContextMenu

UserDblClick

🔌 Suspend/PDF/Business Events

SuspendCompleted / SuspendFailed

PrintToPdfCompleted / PrintToPdfFailed

OnGetCookiesFull

📐 Enum Reference

wv2MouseButton

wv2ShiftState

wv2ScriptDialogKind

wv2PermissionKind

wv2PermissionState

EnumCertificateErrorAction