c# - CodeDomProvider 代码生成因某些 Linq 语法而失败

Question

我正在使用 CodeDomProvider to compile some Linq code并动态执行查询。但是，我遇到了一个非常奇怪的问题。

如果我在生成代码中的 Linq 查询看起来像这样，一切正常:

namespace Dynamic
{
    using System.Linq;
    using System.Collections.Generic;

    public static class Query
    {
        public static int GetRecords()
        {
            MyData.Data.DataMart container = new MyData.Data.DataMart();
            return (container.EventDetails).Count();
        }
    }
}

编译和运行都很好。但是，如果我将 linq 查询更改为以下内容，则它无法编译:

return (from e in container.EventDetails select e).Count();

如果我把它作为静态代码，它工作正常，但如果我尝试用 CodeDomProvider 编译它，它会失败(而且我还没有找到任何好的方法来获取关于它失败原因的错误消息)。我想使用 from-in-select 语法样式，因为这将使我更容易生成 linq 查询，但我无法弄清楚为什么它们不编译。

您可以在本文顶部的链接中看到我用来编译此片段的一些代码。

谢谢!

编辑: 从我链接到的帖子中复制代码:

CodeDomProvider provider = CodeDomProvider.CreateProvider("CSharp");
CompilerParameters cp = new CompilerParameters();
cp.GenerateInMemory = true;
cp.ReferencedAssemblies.Add("mscorlib.dll");
cp.ReferencedAssemblies.Add("System.dll");
cp.ReferencedAssemblies.Add("System.Core.dll");
cp.ReferencedAssemblies.Add("System.Data.Linq.dll");
cp.ReferencedAssemblies.Add("System.Data.Entity.dll");
cp.ReferencedAssemblies.Add("MyApp.Data.dll");

var results = provider.CompileAssemblyFromSource(cp, source);
var assm = results.CompiledAssembly; 

Edit2: 就异常而言，我在倒数第二行代码 (var results = ...) 中遇到异常。异常是 BadImageFormatException:

Could not load file or assembly '0 bytes loaded from System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. An attempt was made to load a program with an incorrect format

Answer 1

这似乎对我有用:

    static void Main(string[] args)
    {
        string sourceCode = @"namespace Dynamic {
using System.Linq;
using System.Collections.Generic;

public static class Query
{
    public static int GetRecords()
    {
        MyApp.Data.DataMart container = new MyApp.Data.DataMart();
        //return (container.EventDetails).Count();
        return (from e in container.EventDetails select e).Count();
    }
} }";

        string sDynamDll = "Dynamic.dll";
        string sDynamClass = "Query";
        string sDynamMethod = "GetRecords";

        System.CodeDom.Compiler.CompilerParameters cp = new CompilerParameters();
        cp.GenerateExecutable = false;
        cp.GenerateInMemory = true;
        cp.OutputAssembly = sDynamDll;
        cp.ReferencedAssemblies.Add("mscorlib.dll");
        cp.ReferencedAssemblies.Add("System.dll");
        cp.ReferencedAssemblies.Add("System.Core.dll");
        cp.ReferencedAssemblies.Add("System.Data.Linq.dll");
        cp.ReferencedAssemblies.Add("System.Data.Entity.dll");
        cp.ReferencedAssemblies.Add("MyApp.Data.dll");

        var providerOptions = new Dictionary<string, string>();
        providerOptions.Add("CompilerVersion", "v4.0");
        CodeDomProvider compiler = CodeDomProvider.CreateProvider("C#", providerOptions);
        CompilerResults cr = compiler.CompileAssemblyFromSource(cp, sourceCode);
        if (cr.Errors.HasErrors)
        {
            StringBuilder errors = new StringBuilder("Compiler Errors :\r\n");
            foreach (CompilerError error in cr.Errors)
            {
                errors.AppendFormat("Line {0},{1}\t: {2}\n", error.Line, error.Column, error.ErrorText);
            }
        }

        // verify assembly
        Assembly theDllAssembly = null;
        if (cp.GenerateInMemory)
            theDllAssembly = cr.CompiledAssembly;
        else
            theDllAssembly = Assembly.LoadFrom(sDynamDll);

        Type theClassType = theDllAssembly.GetType(sDynamClass);

        foreach (Type type in theDllAssembly.GetTypes())
        {
            if (type.IsClass == true)
            {
                if (type.FullName.EndsWith("." + sDynamClass))
                {
                    theClassType = type;
                    break;
                }
            }
        }

        // invoke the method
        if (theClassType != null)
        {
            object[] method_args = new object[] { };

            Object rslt = theClassType.InvokeMember(
                sDynamMethod,
              BindingFlags.Default | BindingFlags.InvokeMethod,
                   null,
                   null, // for static class
                   method_args);

            Console.WriteLine("Results are: " + rslt.ToString());
        }

        Console.ReadKey();
    }