Here is a way of detecting search engine (Google, live…) crawlers,spiders etc..

[code:c#]
            System.Web.HttpBrowserCapabilities clientBrowserCaps = Request.Browser;
            if (((System.Web.Configuration.HttpCapabilitiesBase)clientBrowserCaps).Crawler)
            {
                Response.Write ( "Browser is a search engine.");
            }
            else
            {
               Response.Write ("Browser is not a search engine.");
            } 

//Here is another approach..

            if (Request.ServerVariables["HTTP_USER_AGENT"].Contains("Googlebot"))
            {
                //log Google bot visit
            }
            else if (Request.ServerVariables["HTTP_USER_AGENT"].Contains("msnbot"))
            {
                //log MSN bot visit
            }
            else if (Request.ServerVariables["HTTP_USER_AGENT"].Contains("Yahoo"))
            {
                //log yahoo bot visit
            }
            else
            {
                //similarly you can check for other search engines
            }

[/code]

Here is a small code to remove spaces from textbox's text in onblur event.

<asp:TextBox ID="TextBox2" runat="server" onblur="javascript:value=value.replace(/\s/g,'');"></asp:TextBox>

To remove HTML tags..

<asp:textbox id="TextBox2" runat="server" onblur="this.value = this.value.replace(/<\/?[^>]+>/gi, '');">
</asp:textbox>

Please let me know, if you have any issues.

Regular expression for validating time part: (([0-1][0-9])|([2][0-3])):([0-5][0-9])

The browser back button cannot be disabled as the browser security will not allow this. If you want user to stay on the same page, even if user presses back button, try this java script..

<script language="JavaScript">

javascript:window.history.forward(1);

</script>

What if the JavaScript is disabled by the client, then this code doesn't work. And also it works great in IE, but not in other browsers. So I do not highly recommend using this.

Here is another solution for back button problem..

Add this code to Page_load

Response.Cache.SetCacheability(HttpCacheability.NoCache);

Response.Cache.SetExpires(DateTime.Now); 

The above code will disable page cache. Since the page is not being cached on the browser, the page will be reloaded when the user hits the back button.

HTTP(web page) is stateless, so we cannot know whether the Session has really expired without sending a page request back to the server. If you want to redirect the page immediately(with out any user action) after session expires consider this approach.

Response.AppendHeader("Refresh",Convert.ToString((Session.Timeout * 60)+ 10)+";URL=Login.aspx");

Add this line of code to page_Load.

One of the new controls in ASP.NET 3.5 is ListView. It resembles the GridView control, except that it displays data by using user-defined templates instead of row fields.

The ListView control supports the following features:

ü  Support for binding to data source controls such as SqlDataSource, LinqDataSource, and ObjectDataSource.

ü  Customizable appearance through user-defined templates and styles.

ü  Built-in sorting capabilities.

ü  Built-in update and delete capabilities.

ü  Built-in insert capabilities.

ü  Support for paging capabilities by using a DataPager control.

ü  Built-in item selection capabilities.

ü  Programmatic access to the ListView object model to dynamically set properties, handle events, and so on.

ü  Multiple key fields.

To maintain cursor position on every page, set following code in web.config file

<system.web>             

        <pages maintainScrollPositionOnPostBack="true"></pages>

</system.web> 

Here is sample code for TextBox Validation to allow Numbers only.

[code:c#]

[/code]

In Code behind add this function to "onkeyup" event for TextBox

[code:c#]

TextBox1.Attributes.Add("onkeypress", "CheckTextBox(this)");

[/code]

Some times we need to auto-refresh page after few seconds. you can do it with Meta Refresh tags

Where content '180' is the number of seconds.

Another approach is by addding HTTP header..

[code:c#]

[/code]

Here is sample code for adding tooltip to DropDownList. The key here is adding "title" attribute to the list items in DataBound event.

<asp:DropDownList ID="DropDownList1" runat="server" ondatabound="DropDownList1_DataBound">
</asp:DropDownList>

protected void DropDownList1_DataBound(object sender, EventArgs e)
{
    DropDownList ddl = sender as DropDownList;
    if (ddl != null)
    {
        foreach (ListItem li in ddl.Items)
        {
           li.Attributes["title"] = li.Text; // setting text value of item as tooltip

        }
    }

}