C# Windows.Forms.WebBrowser scaling

问题

I have a WebBrowser control in my Windows Forms app and want to change the "zoom level" of the HTML page I am loading (in my case Bing map).

I expected to find ways to do this at the 'Document' property level, but there is no zoom or height/width/size property to play with (there is at the browser level but I don't want to resize the control itself).

Attached are pics of what I want to do. Any thoughts? Thanks.

Browser zooming issue

回答1:

Jimi is basically right. But I will go ahead and give you the full code/explanation.

You want to add a COM reference to Microsoft Internet Controls so you have access to ShDocVw.

using System;
using System.Windows.Forms;

namespace winforms
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            webBrowser1.Navigate(new Uri("http://www.google.com"));
            webBrowser1.DocumentCompleted += WebBrowser1_DocumentCompleted;
        }

        private void WebBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            var browser = webBrowser1.ActiveXInstance as SHDocVw.InternetExplorer;
            browser.ExecWB(SHDocVw.OLECMDID.OLECMDID_OPTICAL_ZOOM, SHDocVw.OLECMDEXECOPT.OLECMDEXECOPT_DODEFAULT,200 ,IntPtr.Zero );
        }
    }
}

The 200 represents the zoom level.EG 200% zoom. If you did 50% zoom, that would be zooming out.In other words values less than 100 mean zooming out, and values greater than 100 are zooming in. Possible Values range from 10-1000.

Documnetation Links

OLECMDID
OLECMDEXECOPT
ShDcVw.InternetExplorer
ExecWB method
IE Architecture, IE Architecture 2
IE Hosting and Re-Use
Interop with Unmanaged Code
COM Interop Architecture
Introduction to COM Interop (VB)
Importing Type Libraries as Assemblies
COM To .Net Datatypes

Unfortunately, many of the COM components are documented for C++ developers not C# as COM is a C++ paradigm around binary compatibility. And thus in C# we can interop with these COM objects that were originally written in C++.

The other trick you have to remember about COM is that each time new functionality is added, it gets added to a new interface. E.G. IHTMLDocument2 IHTMLDocument3, IHTMLDocument4, etc. So you need to know which interface you actually want to cast your COM object to.

来源：https://stackoverflow.com/questions/48047110/c-sharp-windows-forms-webbrowser-scaling

标签

winforms

webbrowser-control