Tod1d's Thought Process

Problem

When converting a web site from Visual Studio 2005 beta 2 to the non-beta version released on 11/07/2005, you receive the following error message when you try to compile the web site:

'SomePage_aspx' does not implement interface member 'System.Web.UI.ICallbackEventHandler.RaiseCallbackEvent(string)'. 'SomePage_aspx.RaiseCallbackEvent(string)' is either static, not public, or has the wrong return type.

Solution

1. Open the file SomePage.aspx.cs

2. Create a member variable to hold the string to be returned

public string ajaxReturnString = "";

3. Add the following function to the page:

public string GetCallbackResult()
{
    return ajaxReturnString;
}

3. Change your existing RaiseCallbackEvent() function in two ways:
a. Change the return type form string to void.
b. Replace the code that used to return a string with code that sets the ajaxReturnString variable to the string value you wish to return. Then call return;

public void RaiseCallbackEvent(string eventArgument)
{
    ajaxReturnString = GetStringValueToReturn(eventArgument);
    return;
}

Resources:

• Implementing Client Callbacks Without Postbacks in ASP.NET Web Pages
• Google Groups: ASP.NET 2 ICallbackEventHandler