CallByName Method

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Description

Calls a JavaScript function synchronously of the global scope and returns its result.

Syntax

Visual Basic
Public Function CallByName( _ ByVal Name As String, _ ByVal Arguments As Variant _ ) As Variant

Parameters

Name: The JavaScript function name to call.
Arguments: An OLE/COM Variant passed to the JavaScript function.

Return Type

An OLE/COM Variant returned from by the JavaScript function.

Remarks

The simplest way to call a JavaScript function in WebKitX is WebKitX.CallByName(Name, Variant) method. You can pass to JavaScript function arbitrary arguments using an OLE/COM Variant and receive the function's result value, as an OLE/COM Variant too.

Execution of CallByName is IPC-synchronous and this method is an elegant alternative to Eval code as you can pass back-and-forth your variables without stringifying them.

OLE/COM Variants to V8 Values Conversion

WebKitX has a powerful OLE/COM Variant to Google V8 Value bi-directional converter that works both for Scalar and Array values, including nested array values (arrays of arrays of variants). This conversion mechanism is available to any WebKitX method transmitting and/or returning an OLE/COM Variant, such as CallByName, JSCallBack and DispatchEvent.

Currently serialization of VT_DISPATCH is not supported and therefore you cannot pass OLE/COM Objects to JavaScript.
On the OLE/COM side, to pass multiple arguments to a JavaScript callback function you need to wrap them in a Variant Array of Variants.
On the JavaScript side, you can return V8 Scalar or V8 Array values to OLE/COM side, including nested V8 Arrays.

WebKitX can serialize V8 scalar Boolean, Number, String, Null, Date values and Array of [Boolean or Number or String or Null or Date or Array] V8 values.

Google V8 Arrays are always returned as Variant Arrays of Variants. On the receiving OLE/COM side the scalars are converted to a Variant of equivalent scalar type and Arrays are converted into a Variant Array of Variants.

Example

Example (Visual Basic)
Example (C#)

Private Sub mnuTestCallByName_Click()
    On Error Resume Next
    Dim s As String
    Dim result As Variant
    s = InputBox("Function to call", , "foo")
    If s = "" Then Exit Sub
    result = WebKitX1.CallByName(s, Array("My Data", 10, 3.14, Date + Time))
    If IsArray(result) Then
        MsgBox Join(result, ", "), vbInformation
    Else
        MsgBox result, vbInformation
    End If
End Sub

private void menuItemTestCallByName_Click(object sender, EventArgs e)
{
    string input = Microsoft.VisualBasic.Interaction.InputBox("Function to call", "HTML5 Pad", "foo", 500, 300);            
    if (input != "")
    {
        object result = WebKitXCEF31.CallByName(input, new[] { "My Data", "10", "3.1", DateTime.Now.ToString() });
        string[] arr = Array.ConvertAll<object, string>((object[])result, Convert.ToString);
        MessageBox.Show(String.Join(",", arr), "HTML5 Pad", MessageBoxButtons.OK, MessageBoxIcon.Information);
    }
}