Com(p)fy
Skip Navigation Links >> Community >> Technology Forums >> Compfy >> Web Development >> ASP.NET >> Client-Side >> Maintaining scroll bar positions in Panel and TextBox controls during partial page updates
Contents
Skip Navigation Links.
CollapseFolder
Web Development ( Posts: 5 Last: 5/22/2010 )
CollapseFolder
ASP.NET ( Posts: 3 Last: 5/22/2010 )
ExpandFolder
Server-Side ( Posts: 2 Last: 5/22/2010 )
CollapseFolder
Client-Side ( Posts: 1 Last: 4/21/2010 )
Text Post
ExpandFolder
ADO.NET ( Posts: 1 Last: 4/21/2010 )
ExpandFolder
Components and Libraries ( Posts: 1 Last: 5/21/2010 )
Folder
ExpandFolder
Compilers ( Posts: 1 Last: 6/20/2010 )
ExpandFolder
 
Maintaining scroll bar positions in Panel and TextBox controls during partial page updates
4/21/2010 11:31:35 AM
Greg
Joined: 4/17/2010
Posts: 6

The ASP.NET Panel controls loose their scroll bar position during a partial page update event. To maintain them, we currently need use additional JavaScript. There some good suggestions on the web of how to do it. Here I'd like to add a convenient way of embedding them into your code. If, for example, we have a Panel control with the MyPanel ID, we can add the following line to the .aspx file after our Panel: 

Code
<%# ScrollManager.Script(MyPanel)%>
 

To support this method call, we create a class that generates the required JavaScript script. Additionally, we could also add the script to the page programmatically using the RegistrClientScriptBlock call as it is shown below.

Code
        public static void Add(Panel c)
        {
            string script = Script(c);
            ScriptManager.RegisterClientScriptBlock(c, typeof(Panel),
                            c.ClientID + "_ScrollManager", script, false);
        }
 

Now, we just need to create the method for generating the JavaScript script for maintaining the scroll bar positions. Please see a possible way of doing it below. Kudos to Andrew Frederick for the JavaScript code, which I have modified. The method take the reference to our Panel control as a parameter because it needs to access the ClientID property of the Panel control. This allows finding the control in the JavaScript function below.

Code
        public static string Script(Control p)
        {
            string scrollLeftVarName = string.Format("{0}_scrollLeftPos", p.ClientID);
            string scrollTopVarName = string.Format("{0}_scrollTopPos", p.ClientID);

            string beginRequestHandlerName = string.Format("{0}_beginRequestHandler", p.ClientID);
            string endRequestHandlerName = string.Format("{0}_endRequestHandler", p.ClientID);

            return
                "<script type='text/javascript'>" +
                "var " + scrollLeftVarName + "," + scrollTopVarName + ";" +
                "if(typeof(Sys) != 'undefined' && Sys != null)" +
                "{" +
                    "var prm = Sys.WebForms.PageRequestManager.getInstance();" +
                    "prm.add_beginRequest(" + beginRequestHandlerName + ");" +
                    "prm.add_endRequest(" + endRequestHandlerName + ");" +
                "}" +
                "function " + beginRequestHandlerName + "(sender, args)" +
                "{" +
                    "var c = $get('" + p.ClientID + "');" +
                    "if(typeof(c) != 'undefined' && c != null)" +
                    "{" +
                        scrollLeftVarName + " = c.scrollLeft;" +
                        scrollTopVarName + " = c.scrollTop;" +
                    "}" +
                "}" +
                "function " + endRequestHandlerName + "(sender, args)" +
                "{" +
                    "var c = $get('" + p.ClientID + "');" +
                    "if(typeof(c) != 'undefined' && c != null)" +
                    "{" +
                        "c.scrollLeft = " + scrollLeftVarName + ";" +
                        "c.scrollTop = " + scrollTop​​VarName + ";" +
                    "}" +
                "}" +
                "</script>";
        }
 

 

Replies: Page: First Last  Posts/Page:
  Page: First Last  Posts/Page:


Registered users:
8
Users online:
1
Folders total:
18
Posts total:
6
Server timezone (for anonymous users):
(UTC-08:00) Pacific Time (US & Canada)
Powered by Com(p)fy