Metadata file not found - Data.Entity.Model

错误    3    正在编译转换: 未能找到元数据文件“F:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\Tools\..\IDE\Microsoft.Data.Entity.Design.DatabaseGeneration.dll”    E:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE\Extensions\Microsoft\Entity Framework Tools\DBGen\SSDLToSQL10.tt    1    1    杂项文件

原错误信息：

纠结了一半天，总算在 stackoverflow 找到了答案，

http://stackoverflow.com/questions/19664833/metadata-file-not-found-data-entity-model#

（没读懂英文的可以看我下面的分析）

问题简单分析，看下创建 EF 生成模型时候产生的 SSDLToSql10.tt（这是用于 Code First 模式下生成的一个模板文件，主要是用来生成一个 DLL SQL SCRIPT [此处没深入了解，如有不妥请指教]）

 <#
 //---------------------------------------------------------------------
 // <copyright file="SsdlToSql10.tt" company="Microsoft">
 //      Copyright (c) Microsoft Corporation.  All rights reserved.
 // </copyright>
 //---------------------------------------------------------------------
 // This T4 template generates T-SQL from an instance of
 // System.Data.Metadata.Edm.StoreItemCollection, an object representation
 // of the SSDL. This T-SQL is compatible with SQL , , , CE, and Azure databases.
 //---------------------------------------------------------------------
 // Note: We will resolve all paths in assembly directives at runtime, taking
 // macros and environment variables into account (e.g. $(ProjectDir), %VS120COMNTOOLS% etc.)
 #>
 <#@ assembly name="System.Core" #>
 <#@ assembly name="%VS120COMNTOOLS%..\IDE\Microsoft.Data.Entity.Design.DatabaseGeneration.dll"#>
 <#@ assembly name="%VS120COMNTOOLS%..\IDE\EntityFramework.dll"#>
 <#@ assembly name="%VS120COMNTOOLS%..\IDE\EntityFramework.SqlServer.dll" #>
 <#@ assembly name="%VS120COMNTOOLS%..\IDE\EntityFramework.SqlServerCompact.dll" #>
 <#@ import namespace="System.Linq" #>
 <#@ import namespace="System.Text" #>
 <#@ import namespace="System.Collections.Generic" #>
 <#@ import namespace="System.Data.Entity" #>
 <#@ import namespace="System.Data.Entity.Core.Metadata.Edm" #>
 <#@ import namespace="Microsoft.Data.Entity.Design.DatabaseGeneration" #>
 <#@ import namespace="System.Runtime.Remoting.Messaging" #>
 <#@ import namespace="System.Text.RegularExpressions" #>
 <#@ template language="C#" debug="true" hostspecific="true" #>
 <#@ include file="GenerateTSQL.Utility.ttinclude"#>
 <#@ output extension = ".sql" #>
 <#

 // +++++++++++++++++++++++++++++++++++++++++++++++++
 // Setup for the template (initializing variables, etc.)
 // +++++++++++++++++++++++++++++++++++++++++++++++++

     string databaseName = this.GetInput<string>(EdmParameterBag.ParameterName.DatabaseName.ToString());
     string edmxPath = this.GetInput<string>(EdmParameterBag.ParameterName.EdmxPath.ToString());
     Version targetVersion = this.GetInput<Version>(EdmParameterBag.ParameterName.TargetVersion.ToString());

     DbConfiguration.SetConfiguration(new TemplateDbConfiguration());

     if (false == InitializeAndValidateExistingStore())
     {
 #>
 -- Warning: There were errors validating the existing SSDL. Drop statements
 -- will not be generated.
 <#
     }
 #>
 -- --------------------------------------------------
 <#
     if (this.IsSQLCE) {
 #>
 -- Entity Designer DDL Script for SQL Server Compact Edition
 <#
     } else {
 #>
 -- Entity Designer DDL Script for SQL Server , ,  and Azure
 <#
     }
 #>
 -- --------------------------------------------------
 -- Date Created: <#=DateTime.Now#>
 <#
     if (!String.IsNullOrEmpty(edmxPath))
     {
 #>
 -- Generated from EDMX file: <#=Id(edmxPath)#>
 <#
     }
 #>
 -- --------------------------------------------------

 <#  if (!this.IsSQLCE)
     {
 #>
 SET QUOTED_IDENTIFIER OFF;
 GO
 <#  if (!String.IsNullOrEmpty(databaseName))
     {
 #>
 USE [<#=Id(databaseName)#>];
 GO
 <#
     }
     foreach (string unescapedSchemaName in (from es in Store.GetAllEntitySets() select es.GetSchemaName()).Distinct())
     {
 #>
 IF SCHEMA_ID(N'<#=Lit(unescapedSchemaName)#>') IS NULL EXECUTE(N'CREATE SCHEMA [<#=Id(unescapedSchemaName)#>]');
 <#
     }
 #>
 GO
 <#  } #>

 -- --------------------------------------------------
 -- Dropping existing FOREIGN KEY constraints
 <#  if (this.IsSQLCE)
     {
 #>
 -- NOTE: if the constraint does not exist, an ignorable error will be reported.
 <#  } #>
 -- --------------------------------------------------

 <#
     foreach (AssociationSet associationSet in ExistingStore.GetAllAssociationSets())
     {
         ReferentialConstraint constraint = associationSet.ElementType.ReferentialConstraints.Single();
         string constraintName = Id(WriteFKConstraintName(constraint));
         AssociationSetEnd dependentSetEnd = associationSet.AssociationSetEnds.Where(ase => ase.CorrespondingAssociationEndMember == constraint.ToRole).Single();
         string schemaName = Id(dependentSetEnd.EntitySet.GetSchemaName());
         string dependentTableName = Id(dependentSetEnd.EntitySet.GetTableName());

         if (!this.IsSQLCE)
         {
 #>
 IF OBJECT_ID(N'[<#=Lit(schemaName)#>].[<#=Lit(constraintName)#>]', 'F') IS NOT NULL
 <#      } #>
     ALTER TABLE <# if (!IsSQLCE) {#>[<#=schemaName#>].<#}#>[<#=dependentTableName#>] DROP CONSTRAINT [<#=constraintName#>];
 GO
 <#
     }
 #>

 -- --------------------------------------------------
 -- Dropping existing tables
 <#  if (this.IsSQLCE)
     {
 #>
 -- NOTE: if the table does not exist, an ignorable error will be reported.
 <#  } #>
 -- --------------------------------------------------

 <#
     foreach (EntitySet entitySet in ExistingStore.GetAllEntitySets())
     {
         string schemaName = Id(entitySet.GetSchemaName());
         string tableName = Id(entitySet.GetTableName());

         if (!this.IsSQLCE)
         {
 #>
 IF OBJECT_ID(N'[<#=Lit(schemaName)#>].[<#=Lit(tableName)#>]', 'U') IS NOT NULL
 <#      } #>
     DROP TABLE <# if (!IsSQLCE) {#>[<#=schemaName#>].<#}#>[<#=tableName#>];
 GO
 <#
     }
 #>

 -- --------------------------------------------------
 -- Creating all tables
 -- --------------------------------------------------

 <#
     foreach (EntitySet entitySet in Store.GetAllEntitySets())
     {
         string schemaName = Id(entitySet.GetSchemaName());
         string tableName = Id(entitySet.GetTableName());
 #>
 -- Creating table '<#=tableName#>'
 CREATE TABLE <# if (!IsSQLCE) {#>[<#=schemaName#>].<#}#>[<#=tableName#>] (
 <#
         for (int p = ; p < entitySet.ElementType.Properties.Count; p++)
         {
             EdmProperty prop = entitySet.ElementType.Properties[p];
 #>
     [<#=Id(prop.Name)#>] <#=prop.ToStoreType()#> <#=WriteIdentity(prop, targetVersion)#> <#=WriteNullable(prop.Nullable)#><#=(p < entitySet.ElementType.Properties.Count - ) ? "," : ""#>
 <#
         }
 #>
 );
 GO

 <#
     }
 #>
 -- --------------------------------------------------
 -- Creating all PRIMARY KEY constraints
 -- --------------------------------------------------

 <#
     foreach (EntitySet entitySet in Store.GetAllEntitySets())
     {
         string schemaName = Id(entitySet.GetSchemaName());
         string tableName = Id(entitySet.GetTableName());
 #>
 -- Creating primary key on <#=WriteColumns(entitySet.ElementType.GetKeyProperties(), ',')#> in table '<#=tableName#>'
 ALTER TABLE <# if (!IsSQLCE) {#>[<#=schemaName#>].<#}#>[<#=tableName#>]
 ADD CONSTRAINT [PK_<#=tableName#>]
     PRIMARY KEY <# if (!IsSQLCE) {#>CLUSTERED <#}#>(<#=WriteColumns(entitySet.ElementType.GetKeyProperties(), ',')#> <# if (!IsSQLCE) {#>ASC<#}#>);
 GO

 <#
     }
 #>
 -- --------------------------------------------------
 -- Creating all FOREIGN KEY constraints
 -- --------------------------------------------------

 <#
     foreach (AssociationSet associationSet in Store.GetAllAssociationSets())
     {
         ReferentialConstraint constraint = associationSet.ElementType.ReferentialConstraints.Single();
         AssociationSetEnd dependentSetEnd = associationSet.AssociationSetEnds.Where(ase => ase.CorrespondingAssociationEndMember == constraint.ToRole).Single();
         AssociationSetEnd principalSetEnd = associationSet.AssociationSetEnds.Where(ase => ase.CorrespondingAssociationEndMember == constraint.FromRole).Single();
         string schemaName = Id(dependentSetEnd.EntitySet.GetSchemaName());
         string dependentTableName = Id(dependentSetEnd.EntitySet.GetTableName());
         string principalTableName = Id(principalSetEnd.EntitySet.GetTableName());
 #>
 -- Creating foreign key on <#=WriteColumns(constraint.ToProperties, ',')#> in table '<#=dependentTableName#>'
 ALTER TABLE <#if (!IsSQLCE) {#>[<#=schemaName#>].<#}#>[<#=dependentTableName#>]
 ADD CONSTRAINT [<#=WriteFKConstraintName(constraint)#>]
     FOREIGN KEY (<#=WriteColumns(constraint.ToProperties, ',')#>)
     REFERENCES <# if (!IsSQLCE) {#>[<#=schemaName#>].<#}#>[<#=principalTableName#>]
         (<#=WriteColumns(constraint.FromProperties, ',')#>)
     ON DELETE <#=GetDeleteAction(constraint)#> ON UPDATE NO ACTION;
 <#
         // if the foreign keys are part of the primary key on the dependent end, then we should not add a constraint.
         if (!dependentSetEnd.EntitySet.ElementType.GetKeyProperties().Take(constraint.ToProperties.Count()).OrderBy(r => r.Name).SequenceEqual(constraint.ToProperties.OrderBy(r => r.Name)))
         {
 #>

 -- Creating non-clustered index for FOREIGN KEY '<#=WriteFKConstraintName(constraint)#>'
 CREATE INDEX [IX_<#=WriteFKConstraintName(constraint)#>]
 ON <#if (!IsSQLCE) {#>[<#=schemaName#>].<#}#>[<#=dependentTableName#>]
     (<#=WriteColumns(constraint.ToProperties, ',')#>);
 <#
         }
 #>
 GO

 <#
     }
 #>
 -- --------------------------------------------------
 -- Script has ended
 -- --------------------------------------------------

SSDLToSql10.tt

这里面就可以看到它引用了这几个程序集

<#@ assembly name="System.Core" #>
<#@ assembly name="%VS120COMNTOOLS%..\IDE\Microsoft.Data.Entity.Design.DatabaseGeneration.dll"#>
<#@ assembly name="%VS120COMNTOOLS%..\IDE\EntityFramework.dll"#>
<#@ assembly name="%VS120COMNTOOLS%..\IDE\EntityFramework.SqlServer.dll" #>
<#@ assembly name="%VS120COMNTOOLS%..\IDE\EntityFramework.SqlServerCompact.dll" #>

索性我发现这几个程序集确实没在编译报错的路径中，我直接 copy 粘贴到了指定的目录下甚至还在编译器中引用，编译依旧如此。有点棘手！

最后看了老外的分析，说是 visual studio 安装的环境变量值路径不对，后来才一愣发现真是这个问题

控制面板->系统->高级系统设置->高级->环境变量

最终才明白原来编译的路径依据是根据环境变量来的，真是图样图森破