To explain the solution, here is the complete steps I made

First I had an HTML page without any background:

Then I added some CSS to set a background image :

body
{
   background:url("img/bg.gif") no-repeat fixed left top #9AE4E8;
}

The result was good :

But I wanted to add a second background image on the right bottom :

So I moved my background declaration for the head part of the html file

html
{
 background:url("img/bg.gif") no-repeat fixed left top #9AE4E8;
}

and I added an other background declaration for the body part

body
{
 background:url("img/logobeachrahier_medium.png") no-repeat fixed right bottom ;
}

The background declared for the body is applied over the html one:

I think it’s Pretty good now.

I installed it with the provided product key, and tried to activate it:

Unfortunately, the product key has been already activated for the maximum number of times permitted.

So I asked for a new key, I received it and I tried to change the key

After several researches, I couldn’t find an option to change this key.

I finally tried to repair the installation, so I start the office installer

and  the wanted option was here :

Choose “Enter a product key” then click on Continue

Enter your product key and click on “Continue”.

Then you cant choose if you want to install additional office options

Now it’s activated !

If you just want to change the backcolor or things like that, you can spare some time by using only the ItemTemplate and applying a diffenrent style depending of the index (use of the Container.DataItemIndex property).

example : let’s say that your listview generate a <table> and each ItemTemplate generate a row of this table, just do :

<ItemTemplate>
  <tr class='<%# Container.DataItemIndex % 2 == 0 ? “normal” : “alternating” %>'>
    <td>blah blah</td>
  </tr>
</ItemTemplate>

that’s all you need !

First, declare your ValidationSummary, and a CustomValidator with Display property set to “None”

<asp:CustomValidator ID="ServerErrorCustomValidator"
Display="None" runat="server" ValidationGroup="MyValidationGroup" />

<asp:ValidationSummary ID="AdministrationTaskValidationSummary" runat="server" ValidationGroup="MyValidationGroup"/>

Next, in your application code, when an error occurs : set the CustomValidator’s ErrorMessage and IsValid properties :

ServerErrorCustomValidator.ErrorMessage = "Server error :  error description";
ServerErrorCustomValidator.IsValid = false;

string String1 = "testString";
if (String1== null || String1 == "")
{
// ...
}
else
{
// ...
}

string String1 = "testString";
 if (String1 == null || String1.Length==0)
 {
 // ...
 }
 else
 {
 // ...
 }

 string String1 = "testString";
 if (string.IsNullOrEmpty(String1))
 {
 // ...
 }
 else
 {
 // ...
 }

The last one is more readable.

But what about performances ?

Check this code :

private void CheckForNullOrEmpty()
 {
 int maxIterations = 9999999;

 Console.WriteLine("if (string.IsNullOrEmpty(String1))");
 Stopwatch watch = Stopwatch.StartNew();
 for (int i = 0; i < maxIterations; i++)
 {
 string String1 = "testString";
 if (string.IsNullOrEmpty(String1))
 {
 // ...
 }
 else
 {
 // ...
 }
 }

 watch.Stop();
 Console.WriteLine("\tTime : " + watch.Elapsed.TotalMilliseconds);
 Console.WriteLine(Environment.NewLine);

 Console.WriteLine("if (String1== null || String1 == \"\"");
 watch = Stopwatch.StartNew();
 for (int i = 0; i < maxIterations; i++)
 {
 string String1 = "testString";
 if (String1 == null || String1 == "")
 {
 // ...
 }
 else
 {
 // ...
 }
 }

 watch.Stop();
 Console.WriteLine("\tTime : " + watch.Elapsed.TotalMilliseconds);
 Console.WriteLine(Environment.NewLine);

 Console.WriteLine("if (String1 == null || String1.Length==0)");
 watch = Stopwatch.StartNew();
 for (int i = 0; i < maxIterations; i++)
 {
 string String1 = "testString";
 if (String1 == null || String1.Length == 0)
 {
 // ...
 }
 else
 {
 // ...
 }
 }

 watch.Stop();
 Console.WriteLine("\tTime : " + watch.Elapsed.TotalMilliseconds);
 Console.WriteLine(Environment.NewLine);

 Console.WriteLine(Environment.NewLine);
 Console.WriteLine("Press any key to continue");
 Console.ReadLine();
 }

Output is :

The difference between “String.IsNullOrEmpty” and “check for null then for lenght” is minimal, so prefer the String.IsNullOrEmpty() wich is more readable.

As you can guess, IsNullOrEmpty performs a check for null, then a check for lenght :

If you use Reflector to inspect the String class in the mscorlib, you can see that String.IsNullOrEmpty do the same thing we do in our test :

public static bool IsNullOrEmpty(string value)
{
if (value != null)
{
return (value.Length == 0);
}
return true;
}

the “extra” time comes from the method call

Note : In .Net Framework 4.0: string.IsNullOrWhiteSpace() method appears, but I've not tested yet (link)

using System.Diagnostics;

// ...

Stopwatch myStopWatch = Stopwatch.StartNew();

// some code

myStopWatch.Stop();

Console.WriteLine("{0} ms - {1} ticks", myStopWatch.Elapsed.TotalMilliseconds, myStopWatch.ElapsedTicks);

// ...