1. Add [ValidationProperty] tag to define the value to be validated

[ValidationProperty("Location")]
public partial class LocationInputUserControl : System.Web.UI.UserControl
{
	public string Location
	{
		get
		{
			return LocationTextBox.Text.Trim().ToUpper();
		}
	}
}

2. the ControlToValidate=”” property of validation control on the page should be the ID of the user control, colon(:), then the ID of the control to which ‘value’ is associated.

<asp:RequiredFieldValidator ID="RequiredFieldValidator1" ControlToValidate="LocationInputUserControl1:LocationTextBox"
	runat="server" ErrorMessage="<%$ Resources:ErrorMessage, PleaseEnterLocation %>"
	Text="*" CssClass="errMessage"></asp:RequiredFieldValidator>

/// <summary>
/// Executes a shell command synchronously.
/// </summary>
/// <param name="command">string command</param>
/// <returns>string, as output of the command.</returns>
public void ExecuteCommandSync(string command)
{
	try
	{
		// create the ProcessStartInfo using "cmd" as the program to be run,
		// and "/c " as the parameters.
		// Incidentally, /c tells cmd that we want it to execute the command that follows,
		// and then exit.
		string cmdPath = System.IO.Path.Combine(Environment.SystemDirectory, "cmd.exe");
		System.Diagnostics.ProcessStartInfo procStartInfo = new System.Diagnostics.ProcessStartInfo(cmdPath, "/c" + command);

		Console.WriteLine("Executing Command: " + command);

		// The following commands are needed to redirect the standard output.
		// This means that it will be redirected to the Process.StandardOutput StreamReader.
		procStartInfo.RedirectStandardOutput = true;
		procStartInfo.UseShellExecute = false;

		// Do not create the black window.
		procStartInfo.CreateNoWindow = true;

		// Now we create a process, assign its ProcessStartInfo and start it
		System.Diagnostics.Process proc = new System.Diagnostics.Process();
		proc.StartInfo = procStartInfo;
		proc.Start();

		// Get the output into a string
		string result = proc.StandardOutput.ReadToEnd();

		// Display the command output.
		Console.WriteLine(result);
	}
	catch (Exception objException)
	{
		// Log the exception
		Console.WriteLine(objException.Message);                
	}
}

1. Place the DataPager OUTSIDE the ListView
* Define PagedControlID to the ListView and the PageSize

<asp:DataPager ID="DataPager1" PagedControlID="ResultListView" PageSize="10" runat="server"
OnPreRender="DataPager1_PreRender">
<Fields>
	<asp:NextPreviousPagerField FirstPageText="&lt;&lt;" ShowFirstPageButton="True" ShowNextPageButton="False"
		ShowPreviousPageButton="False" />
	<asp:NumericPagerField />
	<asp:NextPreviousPagerField LastPageText="&gt;&gt;" ShowLastPageButton="True" ShowNextPageButton="False"
		ShowPreviousPageButton="False" />
</Fields>
</asp:DataPager>

2. Load the Data and Save it in ViewState, e.g.

ResultListView.DataSource = ResultDataSet;
ResultListView.DataBind();
ViewState["ResultSet"] = ResultDataSet;

3. Get the result set from the ViewState, and Bind again
* This make the Pager works!!!

protected void DataPager1_PreRender(object sender, EventArgs e)
{
	ResultListView.DataSource = ViewState["ResultSet"];
	ResultListView.DataBind();
}