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Next lesson:
Rendering the Control

Custom Controls

Lesson 3: Web Properties

Basic information regarding Web Properties:

  • They can be used to store things like status information, data and settings for custom controls
  • A web property is different from a normal property because its value is shared and maintained between the client and the server.
  • The engine will generate default Get and Set functions if no custom functions are defined.
  • The functions are called upon whenever a WebGet or WebSet is executed.
  • A custom getter or setter can be implemented by using…
    • set_psPropertyName
    • get_psPropertyName

Several property types exist:

  • Client: value is stored at the client, and sent to the server with each call
  • Server: value is retrieved on the server when needed, but page scoped. When the page is reloaded the value of the web property is lost.
  • ServerSession: same as server, but is session scoped. The value is not lost with the page is reloaded.

Some examples:

  • An example of a property being annotated to make it a web property:
  • To create enumerations in a property, create a, Enum_List, and then reuse the EnumList, with the same previously defined values, in the web property.
  • To create a web property in JavaScript, call on this.prop from within the constructor function.
  • Web property types in DataFlex:
    • Boolean: df.tBool
    • String: df.tString
    • Integer: df.tInt
    • Number: df.tNumber
    • Struct: df.tAdv

  • An example of creating a custom setter in JavaScript…


  1. Open the DataFlex Studio and make sure cWebMsgBuilder.pkg is open.
  2. Create a property integer that will define the maximum length of the message. Set the default to 0 (no limit).
  3. Make it a web property by applying the proper annotation.
    {WebProperty = Client}
    Property Integer piMaxLength 0

  4. Open WebMsgBuilder.js from within the text editor
  5. Create the same property integer for the JavaScript side of the process.
    this.prop(df.tInt, “piMaxLength”, 0);
  6. Add a custom getter that will return a message…
    get_psValue : function () {
         var sMsg = this.aMsgParts.join(“ “);
         return sMsg;
  7. Add the message as a private client-side property that is only visible by the client
    //Private property