根据NuGet的说法,我正在处理的项目已安装System.Net.Http版本4.3.3.它在Web.config文件中具有绑定重定向,以将其重定向到版本4.2.0.0,该版本由于某些原因起作用：

<dependentAssembly>
    <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-4.2.0.0" newVersion="4.2.0.0" />
</dependentAssembly>

我将其更改为指向4.3.3.0,这是NuGet所安装的版本：

<dependentAssembly>
    <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-4.3.3.0" newVersion="4.3.3.0" />
</dependentAssembly>

…但是现在当我尝试调试ASP.NET站点时出现此错误：

Could not load file or assembly 'System.Net.Http' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

=== Pre-bind state information ===
LOG: DisplayName = System.Net.Http
 (Partial)
WRN: Partial binding information was supplied for an assembly:
WRN: Assembly Name: System.Net.Http | Domain ID: 2
WRN: A partial bind occurs when only part of the assembly display name is provided.
WRN: This might result in the binder loading an incorrect assembly.
WRN: It is recommended to provide a fully specified textual identity for the assembly,
WRN: that consists of the simple name, version, culture, and public key token.
WRN: See whitepaper http://go.microsoft.com/fwlink/?LinkId=109270 for more information and common solutions to this issue.
LOG: Appbase = file:///C:/.../Dev/Src/Web/PortalSite/
LOG: Initial PrivatePath = C:\...\Dev\Src\Web\PortalSite\bin
Calling assembly : (Unknown).
===
LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\...\Dev\Src\Web\PortalSite\web.config
LOG: Using host configuration file: C:\...\Documents\IISExpress\config\aspnet.config
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
LOG: Attempting download of new URL file:///C:/.../AppData/Local/Temp/Temporary ASP.NET Files/vs/e31848dc/3694ba06/System.Net.Http.DLL.
LOG: Attempting download of new URL file:///C:/.../AppData/Local/Temp/Temporary ASP.NET Files/vs/e31848dc/3694ba06/System.Net.Http/System.Net.Http.DLL.
LOG: Attempting download of new URL file:///C:/.../Dev/Src/Web/PortalSite/bin/System.Net.Http.DLL.
LOG: Using application configuration file: C:\...\Dev\Src\Web\PortalSite\web.config
LOG: Using host configuration file: C:\...\Documents\IISExpress\config\aspnet.config
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Redirect found in application configuration file: 4.2.0.0 redirected to 4.3.3.0.
LOG: Post-policy reference: System.Net.Http, Version=4.3.3.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
LOG: Attempting download of new URL file:///C:/.../AppData/Local/Temp/Temporary ASP.NET Files/vs/e31848dc/3694ba06/System.Net.Http.DLL.
LOG: Attempting download of new URL file:///C:/.../AppData/Local/Temp/Temporary ASP.NET Files/vs/e31848dc/3694ba06/System.Net.Http/System.Net.Http.DLL.
LOG: Attempting download of new URL file:///C:/.../Dev/Src/Web/PortalSite/bin/System.Net.Http.DLL.
WRN: Comparing the assembly name resulted in the mismatch: Minor Version
ERR: Failed to complete setup of assembly (hr = 0x80131040). Probing terminated.

为了使事情更加混乱,该站点的bin目录中的DLL版本似乎又有所不同：

PS C:\...\Dev\Src\Web\PortalSite\bin> (Get-Item ...\bin\Debug\System.Net.Http.dll).VersionInfo

ProductVersion   FileVersion      FileName
--------------   -----------      --------
4.6.25908.02 ... 4.6.25908.02     C:\...\Dev\Src\Web\PortalSite\bin\System.Net.Http.dll

这是怎么回事？重定向以前是如何工作的,为什么现在不起作用？

解决方法:

事实证明,我的bin目录中的DLL版本实际上是4.2.0.0版本,显然是与Visual Studio 2017捆绑在一起的,而NuGet软件包版本4.3.3中分发的版本是DLL版本4.1.1.2,不是完全使用.令人困惑！但这解释了为什么重定向到DLL 4.2.0.0版本有效而​​重定向到4.3.0.0无效的原因.