namespace Accessdatabase
{
    public partial class _Default : System.Web.UI.Page
    {
      
        protected void Page_Load(object sender, EventArgs e)
        {
            //web.config配置文件取出数据库连接串
            string sqlconnstr=ConfigurationManager.ConnectionStrings ["ConnectionString"].ConnectionString;
            //建立数据库连接对象
            SqlConnection sqlconn = new SqlConnection(sqlconnstr);
            //打开连接对象
            sqlconn.Open();
            Label1 .Text ="成功建立Sql Server 2005 数据库连接";
            //关闭连接对象
            sqlconn.Close();
            sqlconn=null;

        }
        

    }
}
web.config
<connectionStrings>
        <add name="ConnectionString" connectionString="Data Source=.\SQLEXPRESS;         
         AttachDbFilename=|DataDirectory|\Mydatabase.mdf;Integrated Security=Ture;User Instance=Ture"/>
    </connectionStrings>
运行提示出错
“/”应用程序中的服务器错误。
--------------------------------------------------------------------------------

项“integrated security”的值无效。
说明: 执行当前 Web 请求期间，出现未处理的异常。请检查堆栈跟踪信息，以了解有关该错误以及代码中导致错误的出处的详细信息。

异常详细信息: System.ArgumentException: 项“integrated security”的值无效。

源错误:


行 22:             string sqlconnstr=ConfigurationManager.ConnectionStrings ["ConnectionString"].ConnectionString;
行 23:             //建立数据库连接对象
行 24:             SqlConnection sqlconn = new SqlConnection(sqlconnstr);
行 25:             //打开连接对象
行 26:             sqlconn.Open();
 

源文件: F:\\Accessdatabase\Accessdatabase\connection.aspx.cs    行: 24

堆栈跟踪:


[ArgumentException: 项“integrated security”的值无效。]
   System.(String stringValue) +1484539
   System.() +1484544
   System.Data.SqlClient.SqlConnectionString..ctor(String connectionString) +89
   System.Data.SqlClient.SqlConnectionFactory.CreateConnectionOptions(String connectionString, DbConnectionOptions previous) +24
   System.Data.ProviderBase.DbConnectionFactory.GetConnectionPoolGroup(String connectionString, DbConnectionPoolGroupOptions poolOptions, DbConnectionOptions& userConnectionOptions) +125
   System.Data.SqlClient.SqlConnection.ConnectionString_Set(String value) +56
   System.Data.SqlClient.SqlConnection.set_ConnectionString(String value) +4
   System.Data.SqlClient.SqlConnection..ctor(String connectionString) +21
   Accessdatabase._Default.Page_Load(Object sender, EventArgs e) in F:\\Accessdatabase\Accessdatabase\connection.aspx.cs:24
   System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +15
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +33
   System.Web.UI.Control.OnLoad(EventArgs e) +99
   System.Web.UI.Control.LoadRecursive() +47
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1436

 


--------------------------------------------------------------------------------
版本信息: Microsoft .NET Framework 版本:2.0.50727.1433; 版本:2.0.50727.1433

自己解决了
connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\mydatabase.mdf;User Instance=true" providerName="System.Data.SqlClient"

     在中的数据库连接，也可以和中一样。
     web.config
<connectionStrings>
        <add name="ConnectionString" connectionString="Data Source=(local);         
         Initial Catalog=数据库名称;Integrated Security=Ture;"/>
    </connectionStrings>

public static string ConnectionString
{
  get{
      string _connectionString=ConfigureManager.ConnectionStrings[""].ToString();
      string ConStringStrplty=ConfigureManager.appSettings[""]
      if(ConStringStrplty=="true")
      {
        _connectionString=DESEncrypt.Decrypt(_connectionString)
      }
     return _connectionString
   }
}

DBHelper类
public static readonly string ConnectionString=PubConstrant.ConnectionString;