由于错误而无法在Visual Studio中进行调试：“System.Data.dll中发生了'System.Data.SqlClient.SqlException'类型的第一次机会异常”

Question

我对这里可能存在的问题感到茫然。

我有一个网络应用程序。我已经成功地构建了整个事物。我试图在某个页面上浏览调试器。

我设置了断点，然后启动调试器。我在断点处收到此消息：

  

断点当前不会被击中。没有为此文档加载任何符号。

我的调试输出窗口中充满了以下消息：

A first chance exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
A first chance exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
The thread '<No Name>' (0x3300) has exited with code 0 (0x0).
The thread '<No Name>' (0x26dc) has exited with code 0 (0x0).
The thread '<No Name>' (0x2f2c) has exited with code 0 (0x0).
The thread '<No Name>' (0x3394) has exited with code 0 (0x0).
A first chance exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
A first chance exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
A first chance exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
A first chance exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
The thread '<No Name>' (0x31e8) has exited with code 0 (0x0).
A first chance exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
A first chance exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
A first chance exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
A first chance exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll`

有数百个，并且它不断增长，我永远无法达到我的断点。这在Visual Studio 2010和2012中都会发生

我的项目在任何地方都没有System.Data dll，没有在web.config或任何bin目录中引用。

有人知道这是怎么回事吗？