Note: Advice in this article will only work for DotNetBrowser 1.
See the corresponding article for DotNetBrowser 2 here.

DotNetBrowser 1.17 provides the ability to set the default zoom level for the BrowserContext instance during its creation. This property allows you to specify the default zoom level for all browsers which use the same context. All pages which are loaded through these Browser instances will initially have a specified zoom level. To specify the default zoom level, you must set the appropriate property of the BrowserContextParams instance using for context creation.

BrowserContextParams contextParams = new BrowserContextParams("C:\\context");
contextParams.DefaultZoomLevel = 1.5;
BrowserContext context = new BrowserContext(contextParams);

Browser browser = BrowserFactory.Create(context);


Dim contextParams As BrowserContextParams = New BrowserContextParams("C:\context")
contextParams.DefaultZoomLevel = 1.5
Dim context As BrowserContext = New BrowserContext(contextParams)

Dim browser As Browser = BrowserFactory.Create(context)

Please note that the default zoom level cannot be changed after the context is created.