I connect to SQLDB as Follow code
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<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:121ConnectionString %>"
SelectCommand="SELECT [text], [count] FROM [Test] WHERE ([id] = @id)">
<SelectParameters>
--------------
and bind data in DAta list like this
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<asp:Label ID="textLabel" runat="server" Text='<%# Eval("count") %>'></asp:Label><br />
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I want to access the value of DB fiels from code bbehind.I do not want to use Eval command, I want to work with them as a variable. i.e work with "countt" field as Golbal variable on my weform and change it's valut to i.e "count" * 15 = 100
what should I do?

Don't use a DataSource control.

You'll need to use ADO Objects instead, i.e.

SqlConnection MyConnection = new SqlConnection("ConnectionString");
SqlCommand MyCommand = new SqlCommand("SELECT * FROM Table", MyConnection);
MyCommand.CommandType = CommandType.Text;
 
MyConnection.Open();
try
{
   // Use the SqlCommand method here to get the data that you want. You'd usually read it into an SqlDataReader or bind it to a control or something.
}
finally
{
   MyConnection.Close();
}

It's best to put that sort of code into it's own set of classes that will be a DAL (Data Access Layer) and then the DAL classes are used by a set of BLL Classess (Business Logic Layer) which are in turn used by the User Interface Layer. Another way of doing it would be to use Table Adapters.

For more info, take a look at these tutorials:
ASP.NET Developer Center: Data Access: Tutorial 1: Creating a Data Access Layer
ASP.NET Developer Center: Data Access: Tutorial 2: Creating a Business Logic Layer
ASP.NET Developer Center: Tutorial 3: Master Pages and Site Navigation
ASP.NET Developer Center: Tutorial 4: Displaying Data With the ObjectDataSource

Although personally, I'd ignore their bit about ObjectDataSource and just call the Business Logic Layer classes from the code-behind files. DataSource controls can be a pain to work with...