elmah - Error Logging Modules and Handlers for ASP.NET - 1 ： 初体验

elmah（英文）：https://code.google.com/p/elmah/

写作思路：先看结果，然后再说原理

elmah文章基本内容如下

1.安装

2.基本使用

3.详细配置讲解

简介

ELMAH是一个开源项目，其目的是记录和报告在ASP.NET
Web应用程序未处理的异常。

早在2004年9月与Atif阿齐兹和斯科特·米切尔发表在MSDN
Library，其目的是作为一个概念证明，编写自包含的功能与ASP.NET
HTTP模块和处理程序是绝对有可能的，大多有这种特征可能是一篇文章插入没有重新编译和小的改动配置文件的现有应用程序。
为了展示这些概念的文章发表了示例项目，其目的是为了拦截，记录和通知ASP.NET应用程序中发生未处理的异常。
它被赋予ELMAH的名称，错误日志记录模块和处理程序。

1.安装

新建一个MVC项目，在nuget的控制台输入命令回车进行安装：Install-Package elmah

MVC项目详情如下

开发环境

vs 2012

sql server 2012

HomeController：


using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Mvc;


namespace Jean.ElmahSample.Controllers

{

    public class HomeController : Controller

    {

        //

        // GET: /Home/


public ActionResult Index()

        {

            return View();

        }


}

}

Index View ：

运行显示效果：

安装后 web.config 文件内容变为如下图-1-1所示（暂时先不要管里面的内容是什么意思，后面再慢慢解答）

图-1-1


<?xml version="1.0" encoding="utf-8"?>

<!--

  有关如何配置 ASP.NET 应用程序的详细信息，请访问

  http://go.microsoft.com/fwlink/?LinkId=152368

  -->

<configuration>

  <configSections>

    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->

    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />

    <sectionGroup name="elmah">

      <section name="security" requirePermission="false" type="Elmah.SecuritySectionHandler, Elmah" />

      <section name="errorLog" requirePermission="false" type="Elmah.ErrorLogSectionHandler, Elmah" />

      <section name="errorMail" requirePermission="false" type="Elmah.ErrorMailSectionHandler, Elmah" />

      <section name="errorFilter" requirePermission="false" type="Elmah.ErrorFilterSectionHandler, Elmah" />

    </sectionGroup>

  </configSections>

  <connectionStrings>

    <add name="DefaultConnection" providerName="System.Data.SqlClient" connectionString="Data Source=(LocalDb)\v11.0;Initial Catalog=aspnet-Jean.ElmahSample-20140524091142;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\aspnet-Jean.ElmahSample-20140524091142.mdf" />

  </connectionStrings>

  <appSettings>

    <add key="webpages:Version" value="2.0.0.0" />

    <add key="webpages:Enabled" value="false" />

    <add key="PreserveLoginUrl" value="true" />

    <add key="ClientValidationEnabled" value="true" />

    <add key="UnobtrusiveJavaScriptEnabled" value="true" />

  </appSettings>

  <system.web>

    <httpRuntime targetFramework="4.5" />

    <compilation debug="true" targetFramework="4.5" />

    <authentication mode="Forms">

      <forms loginUrl="~/Account/Login" timeout="2880" />

    </authentication>

    <pages>

      <namespaces>

        <add namespace="System.Web.Helpers" />

        <add namespace="System.Web.Mvc" />

        <add namespace="System.Web.Mvc.Ajax" />

        <add namespace="System.Web.Mvc.Html" />

        <add namespace="System.Web.Optimization" />

        <add namespace="System.Web.Routing" />

        <add namespace="System.Web.WebPages" />

      </namespaces>

    </pages>

    <profile defaultProvider="DefaultProfileProvider">

      <providers>

        <add name="DefaultProfileProvider" type="System.Web.Providers.DefaultProfileProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" applicationName="/" />

      </providers>

    </profile>

    <membership defaultProvider="DefaultMembershipProvider">

      <providers>

        <add name="DefaultMembershipProvider" type="System.Web.Providers.DefaultMembershipProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/" />

      </providers>

    </membership>

    <roleManager defaultProvider="DefaultRoleProvider">

      <providers>

        <add name="DefaultRoleProvider" type="System.Web.Providers.DefaultRoleProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" applicationName="/" />

      </providers>

    </roleManager>

    <!--

            If you are deploying to a cloud environment that has multiple web server instances,

            you should change session state mode from "InProc" to "Custom". In addition,

            change the connection string named "DefaultConnection" to connect to an instance

            of SQL Server (including SQL Azure and SQL  Compact) instead of to SQL Server Express.

      -->

    <sessionState mode="InProc" customProvider="DefaultSessionProvider">

      <providers>

        <add name="DefaultSessionProvider" type="System.Web.Providers.DefaultSessionStateProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" />

      </providers>

    </sessionState>

    <httpModules>

      <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" />

      <add name="ErrorMail" type="Elmah.ErrorMailModule, Elmah" />

      <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah" />

    </httpModules>

  </system.web>

  <system.webServer>

    <validation validateIntegratedModeConfiguration="false" />

    <handlers>

      <remove name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" />

      <remove name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" />

      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />

      <add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />

      <add name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />

      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />

    </handlers>

    <modules>

      <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" preCondition="managedHandler" />

      <add name="ErrorMail" type="Elmah.ErrorMailModule, Elmah" preCondition="managedHandler" />

      <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah" preCondition="managedHandler" />

    </modules>

  </system.webServer>

  <runtime>

    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">

      <dependentAssembly>

        <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />

        <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" />

      </dependentAssembly>

      <dependentAssembly>

        <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />

        <bindingRedirect oldVersion="1.0.0.0-4.0.0.0" newVersion="4.0.0.0" />

      </dependentAssembly>

      <dependentAssembly>

        <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />

        <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" />

      </dependentAssembly>

      <dependentAssembly>

        <assemblyIdentity name="EntityFramework" publicKeyToken="b77a5c561934e089" />

        <bindingRedirect oldVersion="0.0.0.0-5.0.0.0" newVersion="5.0.0.0" />

      </dependentAssembly>

      <dependentAssembly>

        <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" />

        <bindingRedirect oldVersion="1.0.0.0-1.3.0.0" newVersion="1.3.0.0" />

      </dependentAssembly>

    </assemblyBinding>

  </runtime>

  <entityFramework>

    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">

      <parameters>

        <parameter value="v11.0" />

      </parameters>

    </defaultConnectionFactory>

  </entityFramework>

  <elmah>

    <!--

        See http://code.google.com/p/elmah/wiki/SecuringErrorLogPages for

        more information on remote access and securing ELMAH.

    -->

    <security allowRemoteAccess="false" />

  </elmah>

  <location path="elmah.axd" inheritInChildApplications="false">

    <system.web>

      <httpHandlers>

        <add verb="POST,GET,HEAD" path="elmah.axd" type="Elmah.ErrorLogPageFactory, Elmah" />

      </httpHandlers>

      <!--

        See http://code.google.com/p/elmah/wiki/SecuringErrorLogPages for

        more information on using ASP.NET authorization securing ELMAH.


<authorization>

        <allow roles="admin" />

        <deny users="*" />

      </authorization>

      -->

    </system.web>

    <system.webServer>

      <handlers>

        <add name="ELMAH" verb="POST,GET,HEAD" path="elmah.axd" type="Elmah.ErrorLogPageFactory, Elmah" preCondition="integratedMode" />

      </handlers>

    </system.webServer>

  </location>

</configuration>

2.基本使用

错误数据源（错误存储的地方）

2.1 存储在内存中

输入地址 http://localhost:5547/home/about

看下图结果

图2-1

输入地址 http://localhost:5547/elmah.axd 
（elmah.axd不是一个真实存在的文件，也不需要我们自己去新建）

看下图结果

图2-2

点击并试一试

RSS FEED

DOWNLOAD LOG

点击图2-2中Details 查看详情如下

默认情况下，错误存储在内存中,错误数量上限为15

修改web.config中elmah节点，并设置错误数量上限为5

(当第6个错误出现时，前面5个存在的错误有一个会被最新的错误记录替换)

<elmah>

    <!--Storing errors in memory-->

    <errorLog type="Elmah.MemoryErrorLog, Elmah" size="5" />

</elmah>

2.2 存储在xml中

修改web.config中elmah节点，如下图

<elmah>

    <!--Storing errors in XML files-->

    <errorLog type="Elmah.XmlFileErrorLog, Elmah" logdata-path="~/App_Data" />

</elmah>

输入地址 http://localhost:5547/home/adjkf

看下图结果

2.3 存储在sql server中

2.3.1 修改web.config文件，关键信息如下


<elmah>

    <!--Storing errors in SQL Server-->

    <errorLog type="Elmah.SqlErrorLog, Elmah" connectionStringName="Elmah.Sql" />

</elmah>


<connectionStrings>

    <!--Northwind为我测试的数据库名称-->

    <add name="Elmah.Sql" connectionString="Data Source=.;Initial Catalog=Northwind;Trusted_Connection=True" />

</connectionStrings>

2.3.2 在数据库里执行一下下面sql脚本（我测试的数据库是Northwind）

执行后会创建一张表ELMAH_Error和3个存储过程


/*


ELMAH - Error Logging Modules and Handlers for ASP.NET

   Copyright (c) 2004-9 Atif Aziz. All rights reserved.


Author(s):


Atif Aziz, http://www.raboof.com

        Phil Haacked, http://haacked.com


Licensed under the Apache License, Version 2.0 (the "License");

   you may not use this file except in compliance with the License.

   You may obtain a copy of the License at


http://www.apache.org/licenses/LICENSE-2.0


Unless required by applicable law or agreed to in writing, software

   distributed under the License is distributed on an "AS IS" BASIS,

   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

   See the License for the specific language governing permissions and

   limitations under the License.


*/


-- ELMAH DDL script for Microsoft SQL Server 2000 or later.


-- $Id: SQLServer.sql 677 2009-09-29 18:02:39Z azizatif $


DECLARE @DBCompatibilityLevel INT

DECLARE @DBCompatibilityLevelMajor INT

DECLARE @DBCompatibilityLevelMinor INT


SELECT  @DBCompatibilityLevel = cmptlevel

FROM    master.dbo.sysdatabases

WHERE   name = DB_NAME()


IF @DBCompatibilityLevel <> 80

    BEGIN


SELECT  @DBCompatibilityLevelMajor = @DBCompatibilityLevel / 10 ,

                @DBCompatibilityLevelMinor = @DBCompatibilityLevel % 10


PRINT N‘

    ===========================================================================

    WARNING!

    ---------------------------------------------------------------------------


This script is designed for Microsoft SQL Server 2000 (8.0) but your

    database is set up for compatibility with version ‘

            + CAST(@DBCompatibilityLevelMajor AS NVARCHAR(80)) + N‘.‘

            + CAST(@DBCompatibilityLevelMinor AS NVARCHAR(80)) + N‘. Although

    the script should work with later versions of Microsoft SQL Server,

    you can ensure compatibility by executing the following statement:


ALTER DATABASE [‘ + DB_NAME()

            + N‘]

    SET COMPATIBILITY_LEVEL = 80


If you are hosting ELMAH in the same database as your application

    database and do not wish to change the compatibility option then you

    should create a separate database to host ELMAH where you can set the

    compatibility level more freely.


If you continue with the current setup, please report any compatibility

    issues you encounter over at:


http://code.google.com/p/elmah/issues/list


===========================================================================

‘

    END

GO


/* ------------------------------------------------------------------------

        TABLES

   ------------------------------------------------------------------------ */


CREATE TABLE [dbo].[ELMAH_Error]

    (

      [ErrorId] UNIQUEIDENTIFIER NOT NULL ,

      [Application] NVARCHAR(60) COLLATE SQL_Latin1_General_CP1_CI_AS

                                 NOT NULL ,

      [Host] NVARCHAR(50) COLLATE SQL_Latin1_General_CP1_CI_AS

                          NOT NULL ,

      [Type] NVARCHAR(100) COLLATE SQL_Latin1_General_CP1_CI_AS

                           NOT NULL ,

      [Source] NVARCHAR(60) COLLATE SQL_Latin1_General_CP1_CI_AS

                            NOT NULL ,

      [Message] NVARCHAR(500) COLLATE SQL_Latin1_General_CP1_CI_AS

                              NOT NULL ,

      [User] NVARCHAR(50) COLLATE SQL_Latin1_General_CP1_CI_AS

                          NOT NULL ,

      [StatusCode] INT NOT NULL ,

      [TimeUtc] DATETIME NOT NULL ,

      [Sequence] INT IDENTITY(1, 1)

                     NOT NULL ,

      [AllXml] NTEXT COLLATE SQL_Latin1_General_CP1_CI_AS

                     NOT NULL

    )

ON  [PRIMARY] TEXTIMAGE_ON [PRIMARY]


GO


ALTER TABLE [dbo].[ELMAH_Error] WITH NOCHECK ADD

CONSTRAINT [PK_ELMAH_Error] PRIMARY KEY NONCLUSTERED ([ErrorId]) ON [PRIMARY]

GO


ALTER TABLE [dbo].[ELMAH_Error] ADD

CONSTRAINT [DF_ELMAH_Error_ErrorId] DEFAULT (NEWID()) FOR [ErrorId]

GO


CREATE NONCLUSTERED INDEX [IX_ELMAH_Error_App_Time_Seq] ON [dbo].[ELMAH_Error]

(

[Application]   ASC,

[TimeUtc]       DESC,

[Sequence]      DESC

)

ON [PRIMARY]

GO


/* ------------------------------------------------------------------------

        STORED PROCEDURES

   ------------------------------------------------------------------------ */


SET QUOTED_IDENTIFIER ON

GO

SET ANSI_NULLS ON

GO


CREATE PROCEDURE [dbo].[ELMAH_GetErrorXml]

    (

      @Application NVARCHAR(60) ,

      @ErrorId UNIQUEIDENTIFIER

    )

AS

    SET NOCOUNT ON


SELECT  [AllXml]

    FROM    [ELMAH_Error]

    WHERE   [ErrorId] = @ErrorId

            AND [Application] = @Application


GO

SET QUOTED_IDENTIFIER OFF

GO

SET ANSI_NULLS ON

GO


SET QUOTED_IDENTIFIER ON

GO

SET ANSI_NULLS ON

GO


CREATE PROCEDURE [dbo].[ELMAH_GetErrorsXml]

    (

      @Application NVARCHAR(60) ,

      @PageIndex INT = 0 ,

      @PageSize INT = 15 ,

      @TotalCount INT OUTPUT

    )

AS

    SET NOCOUNT ON


DECLARE @FirstTimeUTC DATETIME

    DECLARE @FirstSequence INT

    DECLARE @StartRow INT

    DECLARE @StartRowIndex INT


SELECT  @TotalCount = COUNT(1)

    FROM    [ELMAH_Error]

    WHERE   [Application] = @Application


-- Get the ID of the first error for the requested page


SET @StartRowIndex = @PageIndex * @PageSize + 1


IF @StartRowIndex <= @TotalCount

        BEGIN


SET ROWCOUNT @StartRowIndex


SELECT  @FirstTimeUTC = [TimeUtc] ,

                    @FirstSequence = [Sequence]

            FROM    [ELMAH_Error]

            WHERE   [Application] = @Application

            ORDER BY [TimeUtc] DESC ,

                    [Sequence] DESC


END

    ELSE

        BEGIN


SET @PageSize = 0


END


-- Now set the row count to the requested page size and get

    -- all records below it for the pertaining application.


SET ROWCOUNT @PageSize


SELECT  errorId = [ErrorId] ,

            application = [Application] ,

            host = [Host] ,

            type = [Type] ,

            source = [Source] ,

            message = [Message] ,

            [user] = [User] ,

            statusCode = [StatusCode] ,

            time = CONVERT(VARCHAR(50), [TimeUtc], 126) + ‘Z‘

    FROM    [ELMAH_Error] error

    WHERE   [Application] = @Application

            AND [TimeUtc] <= @FirstTimeUTC

            AND [Sequence] <= @FirstSequence

    ORDER BY [TimeUtc] DESC ,

            [Sequence] DESC

    FOR     XML AUTO


GO

SET QUOTED_IDENTIFIER OFF

GO

SET ANSI_NULLS ON

GO


SET QUOTED_IDENTIFIER ON

GO

SET ANSI_NULLS ON

GO


CREATE PROCEDURE [dbo].[ELMAH_LogError]

    (

      @ErrorId UNIQUEIDENTIFIER ,

      @Application NVARCHAR(60) ,

      @Host NVARCHAR(30) ,

      @Type NVARCHAR(100) ,

      @Source NVARCHAR(60) ,

      @Message NVARCHAR(500) ,

      @User NVARCHAR(50) ,

      @AllXml NTEXT ,

      @StatusCode INT ,

      @TimeUtc DATETIME

    )

AS

    SET NOCOUNT ON


INSERT  INTO [ELMAH_Error]

            ( [ErrorId] ,

              [Application] ,

              [Host] ,

              [Type] ,

              [Source] ,

              [Message] ,

              [User] ,

              [AllXml] ,

              [StatusCode] ,

              [TimeUtc]

            )

    VALUES  ( @ErrorId ,

              @Application ,

              @Host ,

              @Type ,

              @Source ,

              @Message ,

              @User ,

              @AllXml ,

              @StatusCode ,

              @TimeUtc

            )


GO

SET QUOTED_IDENTIFIER OFF

GO

SET ANSI_NULLS ON

GO

浏览器输入地址http://localhost:5547/abc123ds

在数据库输入脚本并查看结果如下

SQLite与Oracle的配置与sql server类似，就不重复了，

相关脚本下载地址：https://code.google.com/p/elmah/downloads/list

2.4 手动记录错误

方法：

ErrorSignal.FromCurrentContext().Raise()

现在我们创造2个错误并记录

修改HomeController如下


using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Mvc;

using Elmah;


namespace Jean.ElmahSample.Controllers

{

    public class HomeController : Controller

    {

        //

        // GET: /Home/


public ActionResult Index()

        {

            try

            {

                var t = int.Parse("abc");

            }

            catch (Exception e)

            {

                ErrorSignal.FromCurrentContext().Raise(e); // error 1

                ErrorSignal.FromCurrentContext().Raise(new ArgumentNullException()); // error 2

            }

            return View();

        }


}

}

重新生成

浏览器输入 http://localhost:5547

新开窗口输入 http://localhost:5547/elmah.axd

结果如下

第一次写博客，写的有点长，内容有点啰嗦啊，希望大家能多多包涵。

下节内容预览：

错误自动发送到Email

Error类型过滤或筛选

发生错误跳转到统一错误页面并记录

日志的访问权限设置（重点）

elmah - Error Logging Modules and Handlers for ASP.NET - 1 ：
初体验

时间： 2024-10-29 00:20:04

elmah - Error Logging Modules and Handlers for ASP.NET - 1 ： 初体验的相关文章

Demystifying ASP.NET MVC 5 Error Pages and Error Logging

出处:http://dusted.codes/demystifying-aspnet-mvc-5-error-pages-and-error-logging Error pages and error logging, both so elementary and yet so complex in ASP.NET MVC. Perhaps complex is not entirely true, but it is certainly not very straight forward fo

ubuntu error: SSL modules require the OpenSSL library.

+ ngx_http_echo_module was configured checking for PCRE library ... found checking for PCRE JIT support ... not found checking for OpenSSL library ... not found ./configure: error: SSL modules require the OpenSSL library. You can either do not enable

nginx 编译某个模板的问题./configure: error: SSL modules require the OpenSSL library. You can either do not enable the modules, or install the OpenSSL library into the system, or build the OpenSSL library stati

[email protected]:/usr/local/src/nginx-1.9.8# ./configure --prefix=/usr/local/nginx  --add-module=/usr/local/src/nginx-rtmp-module  --with-htchecking for OS + Linux 4.4.0-116-generic x86_64checking for C compiler ... found + using GNU C compiler + gc

ASP.NET MVC学习---（五）MVC初体验

经过之前n多的铺垫 我们已经大概了解了这个姓m名vc的家伙了 那么今天我们就来体验一把 怎么体验呢? 就来做一个小例子吧~ mvc增删改查的例子 数据库还是之前我们的老朋友 关系图: 表中的数据已填好 T_Users 将就着用着吧,哈哈 现在要求对T_Users表进行增删改查 开搞~ 回到之前新建的mvc项目 在Controllers文件夹下新建一个名为Home的空控制器 当浏览器请求Home下面的Index方法的时候返回什么? 当然是主页面啦 这里我们的主页面就是显示T_Users数据列表 代

HTTP Message Handlers in ASP.NET Web API

https://docs.microsoft.com/en-us/aspnet/web-api/overview/advanced/http-message-handlers A message handler is a class that receives an HTTP request and returns an HTTP response. Message handlers derive from the abstract HttpMessageHandler class. Typic

[PLLogging]*****Error:logging directory does not

下面是笔者在使用使用UIImagePickerController的相册选择这个功能时,遇到了下面的问题: 那么笔者是怎么解决这个问题的呢?首先打开你的模拟器的的照片这个应用,再把照片拖进去照片这个应用,而不是直接把你的照片拖进模拟器然后再去你的相册去使用你的照片,不然很可能会出现上面的错误报警!!笔者也只是误打误撞的解决了这个问题,至于大家有没有更好的解决方法,欢迎留言交流与讨论!!!

asp net core 跨平台初体验

标: 在 ubuntu 16.04 上部署一个 asp.net core 站点,打开网站后显示一段文字. 安装 net core 运行环境:ubuntu 16.04 LTS 1.添加 apt 源 依次执行三条命令 sudo sh -c 'echo "deb [arch=amd64] https://apt-mo.trafficmanager.net/repos/dotnet-release/ xenial main" > /etc/apt/sources.list.d/dotne

asp.net 使用 MongoDB 初体验

首先:驱动 如果asp.net 想使用MongoDB,.net没有自带的链接类.得用第三方或官方的链接类. 当然有很多种驱动,我就不一一介绍了. 今天我就介绍一个我比较常用的驱动-----MongoDB. 接下来,我们还要去下载MongoDB的C#驱动,它可以让我们在C#中使用MongoDB .下载地址:https://github.com/samus/mongodb-csharp 我们在C#访问MongoDB所需的驱动就是项目MongoDB了.编译这个项目就能得到了,文件名:MongoDB.d

elmah oracle

1. <sectionGroup name="elmah"> <section name="security" requirePermission="false" type="Elmah.SecuritySectionHandler, Elmah" /> <section name="errorLog" requirePermission="false" t