ViewStateException Class
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ViewStateException Class

 

Represents the exception that is thrown when the view state cannot be loaded or validated. This class cannot be inherited.

Namespace:   System.Web.UI
Assembly:  System.Web (in System.Web.dll)

System.Object
  System.Exception
    System.Web.UI.ViewStateException

[SerializableAttribute]
public sealed class ViewStateException : Exception, ISerializable

NameDescription
System_CAPS_pubmethodViewStateException()

Initializes a new instance of the ViewStateException class.

NameDescription
System_CAPS_pubpropertyData

Gets a collection of key/value pairs that provide additional user-defined information about the exception.(Inherited from Exception.)

System_CAPS_pubpropertyHelpLink

Gets or sets a link to the help file associated with this exception.(Inherited from Exception.)

System_CAPS_pubpropertyHResult

Gets or sets HRESULT, a coded numerical value that is assigned to a specific exception.(Inherited from Exception.)

System_CAPS_pubpropertyInnerException

Gets the Exception instance that caused the current exception.(Inherited from Exception.)

System_CAPS_pubpropertyIsConnected

Gets a value indicating whether the client is currently connected to the server.

System_CAPS_pubpropertyMessage

Gets debugging information about the HTTP request that resulted in a view-state exception.(Overrides Exception.Message.)

System_CAPS_pubpropertyPath

Gets the path of the HTTP request that resulted in a view-state exception.

System_CAPS_pubpropertyPersistedState

Gets the contents of the view-state string that, when read, caused the view-state exception.

System_CAPS_pubpropertyReferer

Gets the URL of the page that linked to the page where the view-state exception occurred.

System_CAPS_pubpropertyRemoteAddress

Gets the IP address of the HTTP request that resulted in a view-state exception.

System_CAPS_pubpropertyRemotePort

Gets the port number of the HTTP request that resulted in a view-state exception.

System_CAPS_pubpropertySource

Gets or sets the name of the application or the object that causes the error.(Inherited from Exception.)

System_CAPS_pubpropertyStackTrace

Gets a string representation of the immediate frames on the call stack.(Inherited from Exception.)

System_CAPS_pubpropertyTargetSite

Gets the method that throws the current exception.(Inherited from Exception.)

System_CAPS_pubpropertyUserAgent

Gets the browser type of the HTTP request that resulted in a view-state exception.

NameDescription
System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_pubmethodGetBaseException()

When overridden in a derived class, returns the Exception that is the root cause of one or more subsequent exceptions.(Inherited from Exception.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetObjectData(SerializationInfo, StreamingContext)

Initializes a new instance of the ViewStateException class with serialized data.(Overrides Exception.GetObjectData(SerializationInfo, StreamingContext).)

System_CAPS_pubmethodGetType()

Gets the runtime type of the current instance.(Inherited from Exception.)

System_CAPS_pubmethodToString()

Creates and returns a string representation of the current exception.(Inherited from Exception.)

If an exception occurs when the page loads the view-state information, the page creates a ViewStateException object and passes it as an inner exception within an HttpException exception. The HttpException exception is re-thrown to be handled by the application.

The ViewStateException class stores information about the exception in the Message property. If the request has permission to access the ServerVariables property, then the Message property contains the values returned from the RemoteAddress, RemotePort, UserAgent, PersistedState, Referer, and Path properties; otherwise, the Message property contains a generic view-state error message.

A view-state exception can be the result of a Message Authentication Codes (MAC) validation error. If the page attribute enableViewStateMac is set to true, view-state information is encoded with a MAC identifier. When the view-state information is posted back to the server, the page verifies the encoding to ensure that it has not been altered by the user. If the page cannot validate the MAC encoding on the view-state information, it will throw an HttpException exception with the ViewStateException object as an inner exception.

For MAC validation to succeed, the view-state information must be hashed by the same key when it is sent and received. Within a Web farm, the machine key on each server should be set to a common key.

The following code example demonstrates how to implement a method that deserializes a base64-encoded string and returns an ICollection collection of property settings. The Deserialize method can throw an HttpException exception that contains a ViewStateException object as an inner exception. The example shows how you can catch an HttpException exception and retrieve the properties from the ViewStateException object.

private ICollection LoadControlProperties(string serializedProperties)
{

    ICollection controlProperties = null;

    // Create an ObjectStateFormatter to deserialize the properties.
    ObjectStateFormatter formatter = new ObjectStateFormatter();

    try
    {
        // Call the Deserialize method.
        controlProperties = (ArrayList)formatter.Deserialize(serializedProperties);
    }
    catch (HttpException e)
    {
        ViewStateException vse = (ViewStateException)e.InnerException;
        String logMessage;

        logMessage = "ViewStateException. Path: " + vse.Path + Environment.NewLine;
        logMessage += "PersistedState: " + vse.PersistedState + Environment.NewLine;
        logMessage += "Referer: " + vse.Referer + Environment.NewLine;
        logMessage += "UserAgent: " + vse.UserAgent + Environment.NewLine;

        LogEvent(logMessage);

        if (vse.IsConnected)
        {
            HttpContext.Current.Response.Redirect("ErrorPage.aspx");
        }
        else
        {
            throw e;
        }
    }
    return controlProperties;
}

.NET Framework
Available since 2.0

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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