有这么多不同的连接字符串可用：

一般（Windows身份验证）：

  SqlConnection sql = new SqlConnection（Data Source = .\\SQLEXPRESS; Initial Catalog = database; Integrated Security =True）; 
 $ p> 

（SqlServer身份验证）：
  SqlConnection sql = new SqlConnection（Data Source = .\\SQLEXPRESS; Uid = sa; password = sqlserver; database = databasename）; 
 
如果您想了解更多有关连接字符串的信息，请访问：
  http： /www.connectionstrings.com 
 
 
I decided to transfer my project from work to home and I am having some trouble with the connection to the database. This one works on work:

web.config:
  <connectionStrings>
    <add name="ApplicationServices" connectionString="Data Source=XXXXXX\SQLSERVER2008;Persist Security Info=true;Initial Catalog=esResearch;User ID=XXXXXX; Password=XXXXXX"
        providerName="System.Data.SqlClient" />
    <add name="esResearchConnectionString" connectionString="Data Source=XXXXXX\SQLSERVER2008;Initial Catalog=esResearch;Persist Security Info=True;User ID=XXXXXX;Password=XXXXXX"
        providerName="System.Data.SqlClient" />
  </connectionStrings>
app.config:
<connectionStrings>
    <add name="esResearchModels.Properties.Settings.esResearchConnectionString"
        connectionString="Data Source=XXXXXX\SQLSERVER2008;Initial Catalog=esResearch;Persist Security Info=True;User ID=XXXXXX"
        providerName="System.Data.SqlClient" />
    <add name="esResearchModels.Properties.Settings.esResearchConnectionString1"
        connectionString="Data Source=XXXXXX\SQLSERVER2008;Initial Catalog=esResearch;Persist Security Info=True;User ID=XXXXXX;Password=XXXXXX"
        providerName="System.Data.SqlClient" />
    <add name="esResearchModels.Properties.Settings.esResearchConnectionString2"
        connectionString="Data Source=XXXXXX\SQLSERVER2008;Initial Catalog=esResearch;User ID=XXXXXX;Password=XXXXXX"
        providerName="System.Data.SqlClient" />
</connectionStrings>
I guess I do not need all those strings but it works atleast. And this line is used in designer.cs
base(global::esResearchModels.Properties.Settings.Default.esResearchConnectionString2, mappingSource)
I have done the movie sample project on asp.net/mvc and used this connectionstring and this one works on my computer at home.

Web.config:
  <connectionStrings>
    <add name="ApplicationServices"
         connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|aspnetdb.mdf;User Instance=true"
         providerName="System.Data.SqlClient" />

    <add name="MovieDBContext"
        connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;database=Movies;User ID=sa;password=" 
         providerName="System.Data.SqlClient"/>
  </connectionStrings>
Any ideas?
There are so many different connection strings are available:

General(Windows Authentication):
SqlConnection sql=new SqlConnection("Data Source=.\\SQLEXPRESS;Initial Catalog=database;Integrated Security="True");
(SqlServer Authentication):
SqlConnection sql=new SqlConnection("Data Source=.\\SQLEXPRESS;Uid=sa;password=sqlserver;database=databasename");
If you want to know more about connection string, go to:
http://www.connectionstrings.com