这需要一些工作，但肯定不是不可能的。

我所做的是:

在字符串中创建c#源代码(不需要写入文件)， 通过Microsoft.CSharp.CSharpCodeProvider (CompileAssemblyFromSource)运行它 查找生成的类型 并创建该类型的实例(Activator.CreateInstance)

这样您就可以处理已经知道的c#代码，而不必发出MSIL。

但是，如果你的类实现了一些接口(或从一些基类派生)，这是最好的工作，否则调用代码(阅读:编译器)如何知道将在运行时生成的类?

我不知道这种动态类的预期用途，代码生成和运行时编译是可以完成的，但需要一些努力。 也许匿名类型会帮助你，比如:

var v = new { EmployeeID = 108, EmployeeName = "John Doe" };

你可以使用CSharpProvider:

var code = @"
    public class Abc {
       public string Get() { return ""abc""; }
    }
";

var options = new CompilerParameters();
options.GenerateExecutable = false;
options.GenerateInMemory = false;

var provider = new CSharpCodeProvider();
var compile = provider.CompileAssemblyFromSource(options, code);

var type = compile.CompiledAssembly.GetType("Abc");
var abc = Activator.CreateInstance(type);

var method = type.GetMethod("Get");
var result = method.Invoke(abc, null);

Console.WriteLine(result); //output: abc

哇!谢谢你的回答!我添加了一些功能，以创建一个“数据表到json”的转换器，我与您分享。

    Public Shared Sub dt2json(ByVal _dt As DataTable, ByVal _sb As StringBuilder)
    Dim t As System.Type

    Dim oList(_dt.Rows.Count - 1) As Object
    Dim jss As New JavaScriptSerializer()
    Dim i As Integer = 0

    t = CompileResultType(_dt)

    For Each dr As DataRow In _dt.Rows
        Dim o As Object = Activator.CreateInstance(t)

        For Each col As DataColumn In _dt.Columns
            setvalue(o, col.ColumnName, dr.Item(col.ColumnName))
        Next

        oList(i) = o
        i += 1
    Next

    jss = New JavaScriptSerializer()
    jss.Serialize(oList, _sb)


End Sub

在"compileresulttype" sub中，我修改了:

    For Each column As DataColumn In _dt.Columns
        CreateProperty(tb, column.ColumnName, column.DataType)
    Next


Private Shared Sub setvalue(ByVal _obj As Object, ByVal _propName As String, ByVal _propValue As Object)
    Dim pi As PropertyInfo
    pi = _obj.GetType.GetProperty(_propName)
    If pi IsNot Nothing AndAlso pi.CanWrite Then
        If _propValue IsNot DBNull.Value Then
            pi.SetValue(_obj, _propValue, Nothing)

        Else
            Select Case pi.PropertyType.ToString
                Case "System.String"
                    pi.SetValue(_obj, String.Empty, Nothing)
                Case Else
                    'let the serialiser use javascript "null" value.
            End Select

        End If
    End If

End Sub

您还可以使用DynamicExpressions动态地创建类。

因为'Dictionary'有紧凑的初始化器并处理键冲突，所以你会想这样做。

  var list = new Dictionary<string, string> {
    {
      "EmployeeID",
      "int"
    }, {
      "EmployeeName",
      "String"
    }, {
      "Birthday",
      "DateTime"
    }
  };

或者，您可能希望使用JSON转换器将序列化的字符串对象构造为可管理的对象。

然后使用System.Linq.Dynamic;

  IEnumerable<DynamicProperty> props = list.Select(property => new DynamicProperty(property.Key, Type.GetType(property.Value))).ToList();

  Type t = DynamicExpression.CreateClass(props);

剩下的就是使用System.Reflection。

  object obj = Activator.CreateInstance(t);
  t.GetProperty("EmployeeID").SetValue(obj, 34, null);
  t.GetProperty("EmployeeName").SetValue(obj, "Albert", null);
  t.GetProperty("Birthday").SetValue(obj, new DateTime(1976, 3, 14), null);
}  

您还可以使用DynamicObject动态创建类。

public class DynamicClass : DynamicObject
{
    private Dictionary<string, KeyValuePair<Type, object>> _fields;

    public DynamicClass(List<Field> fields)
    {
        _fields = new Dictionary<string, KeyValuePair<Type, object>>();
        fields.ForEach(x => _fields.Add(x.FieldName,
            new KeyValuePair<Type, object>(x.FieldType, null)));
    }

    public override bool TrySetMember(SetMemberBinder binder, object value)
    {
        if (_fields.ContainsKey(binder.Name))
        {
            var type = _fields[binder.Name].Key;
            if (value.GetType() == type)
            {
                _fields[binder.Name] = new KeyValuePair<Type, object>(type, value);
                return true;
            }
            else throw new Exception("Value " + value + " is not of type " + type.Name);
        }
        return false;
    }

    public override bool TryGetMember(GetMemberBinder binder, out object result)
    {
        result = _fields[binder.Name].Value;
        return true;
    }
}

我将所有类字段连同它们的类型和值一起存储在字典_fields中。这两种方法都可以获取或设置一些属性的值。必须使用dynamic关键字创建该类的实例。

使用你的例子:

var fields = new List<Field>() { 
    new Field("EmployeeID", typeof(int)),
    new Field("EmployeeName", typeof(string)),
    new Field("Designation", typeof(string)) 
};

dynamic obj = new DynamicClass(fields);

//set
obj.EmployeeID = 123456;
obj.EmployeeName = "John";
obj.Designation = "Tech Lead";

obj.Age = 25;             //Exception: DynamicClass does not contain a definition for 'Age'
obj.EmployeeName = 666;   //Exception: Value 666 is not of type String

//get
Console.WriteLine(obj.EmployeeID);     //123456
Console.WriteLine(obj.EmployeeName);   //John
Console.WriteLine(obj.Designation);    //Tech Lead

编辑:下面是我的类Field的外观:

public class Field
{
    public Field(string name, Type type)
    {
        this.FieldName = name;
        this.FieldType = type;
    }

    public string FieldName;

    public Type FieldType;
}