FAQ - Frequently Asked Questions

🔄 Initialization and Creation

❓ Q1: WebView2 creation failed — what to do?

Symptom: After calling Initialize, Create or Ready events are not triggered.

Possible Causes:

1. WebView2 Runtime not installed
2. WebView2 version on target machine is too old
3. UserDataFolder path conflict

Solution:

' Check if WebView2 is installed
' Look for path: C:\Program Files (x86)\Microsoft\EdgeWebView\Application

' Specify minimum version number
wv.EnvironmentOptions.TargetCompatibleBrowserVersion = "86.0.616.0"

cWebView2Host has internal retry logic — up to 10 creation attempts, auto-incrementing the UserDataFolder path each time.

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❓ Q2: Should Initialize take a Form object or hWnd?

Both are supported:

wv.Initialize Me.hWnd, "https://vb6.pro"    ' Pass window handle
wv.Initialize Me, "https://vb6.pro"          ' Pass Form object (auto-gets hWnd)

When passing a Form object, Form.hWnd is called internally to get the window handle. The effect is exactly the same.

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❓ Q3: When to use two-parameter Initialize vs one-parameter?

• Two-parameter Initialize(hWnd, url) - Most common, auto-navigates to specified URL
• One-parameter Initialize(hWnd) - Use when you need to configure environment parameters before navigation

' Simple scenario: navigate directly
wv.Initialize Me.hWnd, "https://vb6.pro"

' Advanced scenario: need to configure environment parameters
wv.Initialize Me.hWnd    ' Don't navigate immediately

Private Sub wv_Create()
    ' Configure before navigation
    wv.EnvironmentOptions.UserDataFolder = App.Path & "\UserData"
    wv.Security.CertificateErrorAction = CEA_AlwaysAllow
End Sub

Private Sub wv_Ready()
    wv.Navigate "https://example.com"
End Sub

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🔗 Data Binding

❓ Q4: Must BindUI callback methods be Public?

Yes. BindUI uses CallByName to invoke host methods — VB6's CallByName can only call Public members.

' Correct
Public Sub OnClick(ByVal EventName As String, ByVal Detail As String)

' Incorrect - will not be called
Private Sub OnClick(ByVal EventName As String, ByVal Detail As String)

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❓ Q5: How to get DOM element values with BindUI?

The Detail parameter contains JSON-formatted event details that vary by event type. Manual parsing is required:

Public Sub OnNameInput(ByVal EventName As String, ByVal Detail As String)
    ' Detail example: {"type":"input","value":"User input text"}
    Dim val As String
    val = JsonValue(Detail, "value")
    wv.SetData "name", val
End Sub

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❓ Q6: Can SetData pass arrays or objects?

SetData's Value parameter is Variant, internally generating a JS literal directly. There are two approaches for complex structures:

' Method 1: Use innerHTML attribute binding
wv.BindData "list", "#item-list", "innerHTML"
wv.SetData "list", "<li>Item 1</li><li>Item 2</li>"

' Method 2: Call JS function to process JSON
wv.JsRun "renderList(" & jsonString & ")"

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⚡ JavaScript Execution

❓ Q7: What's the difference between JsRun and ExecuteScript?

Feature	JsRun	ExecuteScript
Execution mode	Synchronous (blocking wait)	Asynchronous (event callback)
Return value	Direct String return	JsAsyncResult event
WithEvents	Not required	Recommended
Typical scenario	Get result immediately	Don't need to wait for result

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❓ Q8: What's the difference between JsRun and Script.Eval?

Feature	JsRun	Script.Eval
Input	JS expression/property path	JS code block (supports return)
Wrapping	Direct execution	Wrapped as function, then executed
Usage	wv.JsRun("document.title")	wv.Script.Eval("return document.title")
Best for	Simple expressions	Complex code blocks

Script.Eval wraps code as function EvalFuncName(){...}, injects and calls it, so return is needed to return values.

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🛡️ Security

❓ Q9: How to ignore HTTPS certificate errors?

Must be set in the Create event, before navigation starts:

Dim WithEvents wv As cWebView2Host

Private Sub Form_Load()
    Set wv = New cWebView2Host
    wv.Initialize Me.hWnd, "https://self-signed.example.com/"
End Sub

Private Sub wv_Create()
    ' Set before navigation
    wv.Security.CertificateErrorAction = CEA_AlwaysAllow
End Sub

If set after the Create event, it will not take effect.

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❓ Q10: How to disable DevTools and context menus?

Private Sub wv_Create()
    wv.AreDevToolsEnabled = False
    wv.AreDefaultContextMenusEnabled = False
End Sub

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🍪 Cookies

❓ Q11: What's the difference between GetCookies and GetCookiesFull?

Method	Retrieval Method	HttpOnly Cookies	Performance
Cookies.GetCookies	document.cookie	Not visible	Fast
Cookies.GetCookiesFull	CDP Network.getCookies	Visible	Slightly slower
Cookies.GetCookiesFullAsync	CDP async	Visible	Non-blocking

For scenarios requiring access to HttpOnly cookies, you must use GetCookiesFull or GetCookiesFullAsync.

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🖥️ Host Environment

❓ Q12: What limitations exist in Access?

Access uses MessageWindowAdapter — the following features are not available:

• Host mouse events (HostMouse*)
• Host keyboard events (HostKeyDown/Up/Press)
• HostFocus / HostBlur events

Workarounds:

• Use BindUI to bind DOM events
• Use UserMouse series events (requires EnableUserMouseEvents = True)

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❓ Q13: How to share or isolate sessions across multiple WebView2 instances?

Controlled via UserDataFolder:

' Shared session: same UserDataFolder
wv1.EnvironmentOptions.UserDataFolder = App.Path & "\UserData"
wv2.EnvironmentOptions.UserDataFolder = App.Path & "\UserData"

' Isolated sessions: different UserDataFolders
wv1.EnvironmentOptions.UserDataFolder = App.Path & "\UserDir\account-001"
wv2.EnvironmentOptions.UserDataFolder = App.Path & "\UserDir\account-002"

Instances sharing a session will share cookies, localStorage, etc. Isolated sessions are completely independent.

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📦 Local Resource Loading

❓ Q14: How to load local HTML files?

Three methods:

' Method 1: Pass local folder path (simplest)
wv.Initialize Me.hWnd, App.Path & "\www"
' Auto-maps to http://vbman2.com/index.html

' Method 2: Virtual host name mapping (recommended, supports https protocol)
wv.Initialize Me.hWnd
' In wv_Ready:
wv.SetVirtualHostNameToFolderMapping "myapp.local", App.Path & "\www"
wv.Navigate "https://myapp.local/index.html"

' Method 3: Load from VB6 resource file (single-file distribution)
wv.Initialize Me.hWnd
' In wv_Ready:
wv.NavigateToString VBMAN2.Res(LoadResData("INDEX.HTML", "WWW")).ReturnString()

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❓ Q15: Cross-origin issues with AJAX requests in local HTML?

When loading via SetVirtualHostNameToFolderMapping, the page runs under the https:// protocol and can normally access external APIs of the same protocol — no file:// protocol restrictions apply.

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Last Updated: 2026-06-24