Question

我尝试从C＃连接到SQL Server数据库，但不断被异常抛出：

System.Data.SqlClient.SqlException when trying to open（）`连接。

我创建了一个简单的Web表单，其中包含两个文本框：usernameTextBox和passwordTextBox，以及一个＆＃39;登录＆＃39;按钮。

目前，仅仅是出于测试目的，我尝试做的是在点击users按钮时将值插入sign in表，这就是我所拥有的到目前为止：

using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _default : System.Web.UI.Page
{
    protected void signInButton_Click(object sender, EventArgs e)
    {
        string connection_str="Data Source=.\\SQLEXPRESS;"+
        "AttachDbFilename=|DataDirectory|\\project.mdf;"+
        "Integrated Security=True;"+
        "User Instance=True";

        SqlConnection connection = new SqlConnection(connection_str);
        connection.Open();

        SqlCommand command = new SqlCommand();
        command.Connection = connection;
        command.CommandText="INSERT INTO users VALUES ('"+userNameTextBox.Text+"','"+passwordTextBox.Text+"');";
        command.ExecuteNonQuery();
        connection.Close();
    }
}

如上所述，这在connection.Open();处失败。

project.mdf文件位于VS Project项目文件夹中，位于＆＃39; App_Data＆＃39;夹。

有没有人知道会导致Open()失败的原因？

如果需要，我还可以提供＆＃39;例外信息＆＃39;

感谢。

顺便说一下，何时建立连接？在“登录按钮处理程序”中，或在“Page_Load”中。处理程序？

修改

System.Data.SqlClient.SqlException was unhandled by user code
  HResult=-2146232060
  Message=Cannot open user default database. Login failed.
Login failed for user 'J***-PC\J***'.
  Source=.Net SqlClient Data Provider
  ErrorCode=-2146232060
  Class=11
  LineNumber=65536
  Number=4064
  Procedure=""
  Server=\\.\pipe\8EDE82F8-E3AA-40\tsql\query
  State=1
  StackTrace:
       at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
       at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
       at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
       at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
       at System.Data.SqlClient.SqlInternalConnectionTds.CompleteLogin(Boolean enlistOK)
       at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, Boolean withFailover)
       at System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString connectionOptions, SqlCredential credential, TimeoutTimer timeout)
       at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance)
       at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData)
       at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)
       at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)
       at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
       at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
       at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)
       at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)
       at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
       at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
       at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
       at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry)
       at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
       at System.Data.SqlClient.SqlConnection.Open()
       at _default.signInButton_Click(Object sender, EventArgs e) in c:\Users\J***\Documents\Visual Studio 2012\Projects\db5774\default.aspx.cs:line 23
       at System.Web.UI.WebControls.Button.OnClick(EventArgs e)
       at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument)
       at System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument)
       at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument)
       at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData)
       at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
  InnerException:

Answer 1

所以例外说：

Message =无法打开用户默认数据库。登录失败。用户'J *** - PC \ J ***'登录失败。

这意味着用户无法访问默认数据库，通常是master。

更改用户以便它可以访问默认数据库，或者更好，将默认值指向另一个数据库。

使用此sql：

alter login [username] with default_database = database_that_user_can_access

或者通过添加以下内容来更改连接字符串：

Database=database_that_user_can_access

Answer 2

试试这个：

  AttachDbFilename=~\..\ProjectName\App_Data\project.mdf

从C＃连接到SQL Server Express

2 个答案: