How to decode viewstate
I need to see the contents of the viewstate of an asp.net page. I looked for a viewstate decoder, found Fridz Onion's ViewState Decoder but it asks for the url of a page to get its viewstate. Since my viewstate is formed after a postback and comes as a result of an operation in an update panel, I cannot provide a url. I need to copy & paste the viewstate string and see what's inside. Is there a tool or a website exist that can help viewing the contents of viewstate?
Solution 1:
Here's an online ViewState decoder:
http://ignatu.co.uk/ViewStateDecoder.aspx
Edit: Unfortunatey, the above link is dead - here's another ViewState decoder (from the comments):
http://viewstatedecoder.azurewebsites.net/
Solution 2:
Use Fiddler and grab the view state in the response and paste it into the bottom left text box then decode.
Solution 3:
Here is the source code for a ViewState visualizer from Scott Mitchell's article on ViewState (25 pages)
using System;
using System.Collections;
using System.Text;
using System.IO;
using System.Web.UI;
namespace ViewStateArticle.ExtendedPageClasses
{
/// <summary>
/// Parses the view state, constructing a viaully-accessible object graph.
/// </summary>
public class ViewStateParser
{
// private member variables
private TextWriter tw;
private string indentString = " ";
#region Constructor
/// <summary>
/// Creates a new ViewStateParser instance, specifying the TextWriter to emit the output to.
/// </summary>
public ViewStateParser(TextWriter writer)
{
tw = writer;
}
#endregion
#region Methods
#region ParseViewStateGraph Methods
/// <summary>
/// Emits a readable version of the view state to the TextWriter passed into the object's constructor.
/// </summary>
/// <param name="viewState">The view state object to start parsing at.</param>
public virtual void ParseViewStateGraph(object viewState)
{
ParseViewStateGraph(viewState, 0, string.Empty);
}
/// <summary>
/// Emits a readable version of the view state to the TextWriter passed into the object's constructor.
/// </summary>
/// <param name="viewStateAsString">A base-64 encoded representation of the view state to parse.</param>
public virtual void ParseViewStateGraph(string viewStateAsString)
{
// First, deserialize the string into a Triplet
LosFormatter los = new LosFormatter();
object viewState = los.Deserialize(viewStateAsString);
ParseViewStateGraph(viewState, 0, string.Empty);
}
/// <summary>
/// Recursively parses the view state.
/// </summary>
/// <param name="node">The current view state node.</param>
/// <param name="depth">The "depth" of the view state tree.</param>
/// <param name="label">A label to display in the emitted output next to the current node.</param>
protected virtual void ParseViewStateGraph(object node, int depth, string label)
{
tw.Write(System.Environment.NewLine);
if (node == null)
{
tw.Write(String.Concat(Indent(depth), label, "NODE IS NULL"));
}
else if (node is Triplet)
{
tw.Write(String.Concat(Indent(depth), label, "TRIPLET"));
ParseViewStateGraph(((Triplet) node).First, depth+1, "First: ");
ParseViewStateGraph(((Triplet) node).Second, depth+1, "Second: ");
ParseViewStateGraph(((Triplet) node).Third, depth+1, "Third: ");
}
else if (node is Pair)
{
tw.Write(String.Concat(Indent(depth), label, "PAIR"));
ParseViewStateGraph(((Pair) node).First, depth+1, "First: ");
ParseViewStateGraph(((Pair) node).Second, depth+1, "Second: ");
}
else if (node is ArrayList)
{
tw.Write(String.Concat(Indent(depth), label, "ARRAYLIST"));
// display array values
for (int i = 0; i < ((ArrayList) node).Count; i++)
ParseViewStateGraph(((ArrayList) node)[i], depth+1, String.Format("({0}) ", i));
}
else if (node.GetType().IsArray)
{
tw.Write(String.Concat(Indent(depth), label, "ARRAY "));
tw.Write(String.Concat("(", node.GetType().ToString(), ")"));
IEnumerator e = ((Array) node).GetEnumerator();
int count = 0;
while (e.MoveNext())
ParseViewStateGraph(e.Current, depth+1, String.Format("({0}) ", count++));
}
else if (node.GetType().IsPrimitive || node is string)
{
tw.Write(String.Concat(Indent(depth), label));
tw.Write(node.ToString() + " (" + node.GetType().ToString() + ")");
}
else
{
tw.Write(String.Concat(Indent(depth), label, "OTHER - "));
tw.Write(node.GetType().ToString());
}
}
#endregion
/// <summary>
/// Returns a string containing the <see cref="IndentString"/> property value a specified number of times.
/// </summary>
/// <param name="depth">The number of times to repeat the <see cref="IndentString"/> property.</param>
/// <returns>A string containing the <see cref="IndentString"/> property value a specified number of times.</returns>
protected virtual string Indent(int depth)
{
StringBuilder sb = new StringBuilder(IndentString.Length * depth);
for (int i = 0; i < depth; i++)
sb.Append(IndentString);
return sb.ToString();
}
#endregion
#region Properties
/// <summary>
/// Specifies the indentation to use for each level when displaying the object graph.
/// </summary>
/// <value>A string value; the default is three blank spaces.</value>
public string IndentString
{
get
{
return indentString;
}
set
{
indentString = value;
}
}
#endregion
}
}
And here's a simple page to read the viewstate from a textbox and graph it using the above code
private void btnParse_Click(object sender, System.EventArgs e)
{
// parse the viewState
StringWriter writer = new StringWriter();
ViewStateParser p = new ViewStateParser(writer);
p.ParseViewStateGraph(txtViewState.Text);
ltlViewState.Text = writer.ToString();
}
Solution 4:
As another person just mentioned, it's a base64 encoded string. In the past, I've used this website to decode it:
http://www.motobit.com/util/base64-decoder-encoder.asp
Solution 5:
Here's another decoder that works well as of 2014: http://viewstatedecoder.azurewebsites.net/
This worked on an input on which the Ignatu decoder failed with "The serialized data is invalid" (although it leaves the BinaryFormatter-serialized data undecoded, showing only its length).