EntityFramework4的POCO模板生成FunctionImport返回空的服务端调用代码

         我们知道Entity Framework 4 默认根据MODEL生成ServerCode, 现在我们使用POCO T4模板。有个小问题，对于那些Function Import的存储过程没有返回值，却没有生成相应的CODE。主要生成于一个DataContext下，通常是XXXXX.Context.tt的模板。打开模板，你可以找到这么一行代码：

if (edmFunction.ReturnParameter == null)

        就是这里了，接下我们自己来修改一下。最后修改完后，如下：

<#
//*********************************************************
//
//    Copyright (c) Microsoft. All rights reserved.
//    This code is licensed under the Microsoft Public License.
//    THIS CODE IS PROVIDED *AS IS* WITHOUT WARRANTY OF
//    ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING ANY
//    IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR
//    PURPOSE, MERCHANTABILITY, OR NON-INFRINGEMENT.
//
//*********************************************************
#>
<#@ template language="C#" debug="false" hostspecific="true"#>
<#@ include file="EF.Utility.CS.ttinclude"#><#@
 output extension=".cs"#><#

CodeGenerationTools code = new CodeGenerationTools(this);
MetadataTools ef = new MetadataTools(this);
MetadataLoader loader = new MetadataLoader(this);
CodeRegion region = new CodeRegion(this);

string inputFile = @"model.edmx";
EdmItemCollection ItemCollection = loader.CreateEdmItemCollection(inputFile);
string namespaceName = code.VsNamespaceSuggestion();

EntityContainer container = ItemCollection.GetItems<EntityContainer>().FirstOrDefault();
if (container == null)
{
    return "// No EntityContainer exists in the model, so no code was generated";
}
#>
//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated from a template.
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

using System;
using System.Data.Objects;
using System.Data.EntityClient;

<#
if (!String.IsNullOrEmpty(namespaceName))
{
#>
namespace <#=code.EscapeNamespace(namespaceName)#>
{
<#
    PushIndent(CodeRegion.GetIndent(1));
}
#>
<#=Accessibility.ForType(container)#> partial class <#=code.Escape(container)#> : ObjectContext
{
    public const string ConnectionString = "name=<#=container.Name#>";
    public const string ContainerName = "<#=container.Name#>";

    #region Constructors

    public <#=code.Escape(container)#>()
        : base(ConnectionString, ContainerName)
    {
<#
        WriteLazyLoadingEnabled(container);
#>
    }

    public <#=code.Escape(container)#>(string connectionString)
        : base(connectionString, ContainerName)
    {
<#
        WriteLazyLoadingEnabled(container);
#>
    }

    public <#=code.Escape(container)#>(EntityConnection connection)
        : base(connection, ContainerName)
    {
<#
        WriteLazyLoadingEnabled(container);
#>
    }

    #endregion

<#
        region.Begin("ObjectSet Properties", 2);

        foreach (EntitySet entitySet in container.BaseEntitySets.OfType<EntitySet>())
        {
#>

    <#=Accessibility.ForReadOnlyProperty(entitySet)#> ObjectSet<<#=code.Escape(entitySet.ElementType)#>> <#=code.Escape(entitySet)#>
    {
        get { return <#=code.FieldName(entitySet) #>  ?? (<#=code.FieldName(entitySet)#> = CreateObjectSet<<#=code.Escape(entitySet.ElementType)#>>("<#=entitySet.Name#>")); }
    }
    private ObjectSet<<#=code.Escape(entitySet.ElementType)#>> <#=code.FieldName(entitySet)#>;
<#
        }

        region.End();

        region.Begin("Function Imports");

        foreach (EdmFunction edmFunction in container.FunctionImports)
        {
            var parameters = FunctionImportParameter.Create(edmFunction.Parameters, code, ef);
            string paramList = String.Join(", ", parameters.Select(p => p.FunctionParameterType + " " + p.FunctionParameterName).ToArray());
            string returnTypeElement = "int";
            if (edmFunction.ReturnParameter == null)
            {
#>

    <#=Accessibility.ForMethod(edmFunction)#> void <#=code.Escape(edmFunction)#>(<#=paramList#>)
    {
<#
            }
            else
            {
                returnTypeElement = code.Escape(ef.GetElementType(edmFunction.ReturnParameter.TypeUsage));
#>

    <#=Accessibility.ForMethod(edmFunction)#> ObjectResult<<#=returnTypeElement#>> <#=code.Escape(edmFunction)#>(<#=paramList#>)
    {
<#
            }

            foreach (var parameter in parameters)
            {
                if (!parameter.NeedsLocalVariable)
                {
                    continue;
                }
#>
        ObjectParameter <#=parameter.LocalVariableName#>;
        if (<#=parameter.IsNullableOfT ? parameter.FunctionParameterName + ".HasValue" : parameter.FunctionParameterName + " != null"#>)
        {
            <#=parameter.LocalVariableName#> = new ObjectParameter("<#=parameter.EsqlParameterName#>", <#=parameter.FunctionParameterName#>);
        }
        else
        {
            <#=parameter.LocalVariableName#> = new ObjectParameter("<#=parameter.EsqlParameterName#>", typeof(<#=parameter.RawClrTypeName#>));
        }

<#
            }
            if (edmFunction.ReturnParameter == null)
            {
#>
        base.ExecuteFunction("<#=edmFunction.Name#>"<#=code.StringBefore(", ", String.Join(", ", parameters.Select(p => p.ExecuteParameterName).ToArray()))#>);
    }
<#
            }
            else
            {
#>
        return base.ExecuteFunction<<#=returnTypeElement#>>("<#=edmFunction.Name#>"<#=code.StringBefore(", ", String.Join(", ", parameters.Select(p => p.ExecuteParameterName).ToArray()))#>);
    }
<#
            }
        }
        region.End();

#>
}
<#
if (!String.IsNullOrEmpty(namespaceName))
{
    PopIndent();
#>
}
<#
}
#>
<#+

private void WriteLazyLoadingEnabled(EntityContainer container)
{
   string lazyLoadingAttributeValue = null;
   string lazyLoadingAttributeName = MetadataConstants.EDM_ANNOTATION_09_02 + ":LazyLoadingEnabled";
   if(MetadataTools.TryGetStringMetadataPropertySetting(container, lazyLoadingAttributeName, out lazyLoadingAttributeValue))
   {
       bool isLazyLoading = false;
       if(bool.TryParse(lazyLoadingAttributeValue, out isLazyLoading))
       {
#>
        this.ContextOptions.LazyLoadingEnabled = <#=isLazyLoading.ToString().ToLowerInvariant()#>;
<#+
       }
   }
}
#>

     把那个inputfile变量的值替换成你的edmx，就可以使用了。将生成这样的代码，注意这个方法返回是void:

    public partial class Entities : ObjectContext
    {

        public void ChangeForumID(string thread, Nullable<int> forum)
        {
            ObjectParameter threadParameter;
            if (thread != null)
            {
                threadParameter = new ObjectParameter("Thread", thread);
            }
            else
            {
                threadParameter = new ObjectParameter("Thread", typeof(string));
            }

            ObjectParameter forumParameter;
            if (forum.HasValue)
            {
                forumParameter = new ObjectParameter("Forum", forum);
            }
            else
            {
                forumParameter = new ObjectParameter("Forum", typeof(int));
            }

            base.ExecuteFunction("ChangeForumID", threadParameter, forumParameter);
        }

     当然你手写也是可以的，不过数量多就很累了。希望这篇POST对您开发有帮助。

作者：Petter Liu
出处：http://www.cnblogs.com/wintersun/
本文版权归作者和博客园共有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。
该文章也同时发布在我的独立博客中-Petter Liu Blog。