Provides an easy way for server code to publish .NET values into JavaScript script code as an encapsulated object. This object basically provides a mechanism for adding key value pairs and embedding
those values into an object that is hosted on the client. Optionally the client values can update the server code on a postback.

To create a client object with server variables you can use this basic code:

// *** Specify page instance and optional name of the client object
ScriptVariables scriptVars = new ScriptVariables(this,"serverVars");
  
// *** Add any values static or dynamic
scriptVars.Add("name", "Rick Strahl");
scriptVars.Add("company", "Rick's \"East\\West\" Trading");
scriptVars.Add("entered", DateTime.Now.AddYears(-10));
scriptVars.Add("counter",12.22M);
 
// *** Add a control's value dynamically at pre render time
scriptVars.AddDynamicValue("txtNameValue", this.txtName, "Text");

Which creates a client object like this:

var serverVars = {
    name: "Rick Strahl",
    company: "Rick's \"East\\West\" Trading",
    entered: new Date(888053450808),
    counter: 12.22,
    txtNameValue: "Rick"
};

Each value added to the collection translates into a property on the generated JavaScript object. Not that you can add fixed values via .Add() and dynamic values that are evaluated pre-render time using AddDynamicValue().

You can also embed client script ids into the page as follows:

// *** Add all Client Ids - note this may cause naming conflicts on duplicate names// *** in separate naming containers. First one wins!scriptVars.AddClientIds(this,true);

which results in the following generated client ids:

var serverVars = {
    name: "Rick Strahl",
    company: "Rick's \"East\\West\" Trading",
    entered: new Date(888054678218),
    counter: 12.22,
    txtNameValue: "Rick",
    headId: "ctl00_head",
    form1Id: "aspnetForm",
    ContentId: "ctl00_Content",
    txtNameId: "ctl00_Content_txtName",
    btnSubmitId: "ctl00_Content_btnSubmit",
    panel1Id: "ctl00_Content_panel1",
    txtPanelTextBoxId: "ctl00_Content_txtPanelTextBox",
    repListId: "ctl00_Content_repList",
    gdvTestId: "ctl00_Content_gdvTest"
};

In this example recursive Ids are generated, but you can also specify a specific container and no-recursion to minimize naming conflicts and proliferation of variables.

Updating Server Variables from the Client

The control also supports POSTing the updated values and optional statebag to the server in a Postback. To do this specify an UpdateMode other than None:

ScriptVariables scriptVars = new ScriptVariables(this,"serverVars");
   scriptVars.UpdateMode =  AllowUpdateTypes.All;
 
   // *** Add any values static or dynamic
   scriptVars.Add("name", "Rick Strahl");
   scriptVars.Add("company", "Rick's \"East\\West\" Trading");
   scriptVars.Add("entered", DateTime.Now.AddYears(-10));
   scriptVars.Add("counter",12.22M);
 
   // *** Read back values assigned to the client object
   if (this.IsPostBack)
   {
       Response.Write(scriptVars.GetValue<string>("name"));
       Response.Write(scriptVars.GetItemValue<string>("Custom"));
       Response.Write(scriptVars.GetItemValue<string>("CustomValue"));
       Response.Write(scriptVars.GetItemValue<DateTime>("curDate"));
       Response.Write(scriptVars.GetValue<DateTime>("entered")); 
   }

Note that values are available only on Postback. Non-postback access causes an exception. On the client you can simply update the properties of the generated object or the _Items collection via .add():

// *** Update Properties to be sent back to server
serverVars.entered = new Date();
serverVars.name = "Jimmy Johnston Jr.";
 
// *** Update _Items 'collection'
serverVars.add("Custom","Rick");
serverVars.add("CustomValue","West Wind");
serverVars.add("curDate",new Date(2001,10,1));

Property values can be read back on the server with scriptVars.GetValue<t>(property) and Items collection values with .GetItemValue<t>(key).