VS 2008 Simple Gridview Control - Connection To SQLServer Not Working

I have a simple .aspx page. Where I need to connect to sql server 2008 and show the records on the page in a gridviewcontrol. It will have Edit button on the gridview control. I am getting some weird message about the connection string.

Error message is:
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentException: Keyword not supported: 'initial catalog'.

Web.config file:

Code:
<connectionStrings>
<add name="ConnectionString_SqlServer" connectionString="Data Source=PricingDB;Initial Catalog=DB1;Integrated Security=True;Connect Timeout=300" providerName="System.Data.SqlClient" />
</connectionStrings>

In the .aspx page this is how I am connecting.

Code:
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:ConnectionString_SqlServer %>"
ProviderName="<%$ ConnectionStrings:ConnectionString.ProviderName %>"
SelectCommand="select name, value from dbo.Pricing order by name asc"
>
</asp:SqlDataSource>