have look on your Web.config page ensure that there is a connectionstring like below
<connectionstrings>
<add name="XtestConnectionString" connectionstring="Data Source=PC-223\SQLEXPRESS2012;Initial Catalog=Xtest;Persist Security Info=True;User ID=sa;Password=12345">
providerName="System.Data.SqlClient" />
/xml></add></connectionstrings>