Assembly: System (in System.dll)
Set this property to true when requests made by this WebProxy object should, if requested by the server, be authenticated using the credentials of the currently logged on user. For client applications, this is the desired behavior in most scenarios. For middle tier applications, such as ASP.NET applications, instead of using this property, you would typically set the Credentials property to the credentials of the client on whose behalf the request is made.
The following table shows the effect of setting the value, based on the value of the Credentials property.
Credentials is set to a null reference (Nothing in Visual Basic).
a null reference (Nothing in Visual Basic)
Any value other than DefaultCredentials or a null reference (Nothing in Visual Basic)
true or false
Setting throws an exception.
If is false, you can change the Credentials property to any credentials. If is true, changing the Credentials property from DefaultCredentials (the value that is set when the property is set to true) will throw an exception.