我在一个名称空间中定义了一个Employee Class，而代码片段就是这样的
delegate bool IsPromotable (Employee employee);
class Program
{
public static void Main(string[] args)
{
List<Employee> empList = new List<Employee>();
empList.Add(new Employee() { EmployeeId = 1, EmployeeName = "A", Salary = 7500, Experience = 2 });
empList.Add(new Employee() { EmployeeId = 2, EmployeeName = "B", Salary = 11500, Experience = 6 });
empList.Add(new Employee() { EmployeeId = 3, EmployeeName = "C", Salary = 14500, Experience = 5 });
empList.Add(new Employee() { EmployeeId = 4, EmployeeName = "D", Salary = 10500, Experience = 7 });
IsPromotable isPromotableObj = new IsPromotable(EnableToPromote);
Employee EmployeeObj = new Employee();
EmployeeObj.PromoteEmployees(empList, isPromotableObj);
}
public static bool EnableToPromote(Employee employee)
{
if (employee.Experience >= 5 && employee.Salary >= 10000)
{
return true;
}
else
return false;
}
}
class Employee
{
public int EmployeeId { get; set; }
public string EmployeeName { get; set; }
public int Salary { get; set; }
public int Experience { get; set; }
public void PromoteEmployees(List<Employee> employeeList, IsPromotable isPromotableObj)
{
foreach (Employee employee in employeeList)
{
if (isPromotableObj(employee))
{
Console.WriteLine(" {0} will be promoted in the next R.P. Cycle ", employee.EmployeeName);
}
}
Console.ReadKey();
}
}
现在，通过反射从单独的命名空间中的一个单独的类中，我想获得Class Type和与之相关的所有其他类型对象。我还想调用PromoteEmployee（）方法。我该怎么做？
Console.WriteLine("***************Loading External assembly*************");
Assembly assembly = Assembly.LoadFrom(@"C:\Users\Chiranjib\Documents\visual studio 2012\Projects\DelegatesSampleApplication\DelegatesSampleApplication\bin\Debug\DelegatesSampleApplication.exe");
Type employeeType = assembly.GetType("DelegatesSampleApplication.Employee"); //Gets the System.Type object for the Employee Class from the just loaded assembly with all it's dependencies
object employeeInstance = Activator.CreateInstance(employeeType);//Create an instance of the Employee Class Type
//sets it's properites
Console.WriteLine("***************Setting External assembly propeties for the second instance*************");
object employeeInstance2 = Activator.CreateInstance(employeeType);
//set's it's properties
Console.WriteLine("***************Creating an array list that will hold these employee instances***************");
List<Object> employeeInstanceList = new List<object>();
employeeInstanceList.Add(employeeInstance);
employeeInstanceList.Add(employeeInstance2);
Console.WriteLine("***************Invoking External assembly methods*************");
var agrsDel = new Object[] {(employeeInstance) => return employeeInstance};
dynamic value = employeeType.InvokeMember("PromoteEmployees", BindingFlags.InvokeMethod | BindingFlags.Instance | BindingFlags.Public, null, employeeInstance, new Object[] {employeeInstanceList,args})});
Console.ReadKey();
但是我得到的错误是agrsDel它不能将lambda表达式转换为对象，其次对象不包含employeeId的定义。我错过了什么？
答案 0 :(得分：1)
我将您的代码更改为使用Delegate.Create委托。这对你有帮助吗？
//var agrsDel = new Object[] {(employeeInstance) => return employeeInstance};
Delegate validationDelegate;
try
{
Type prog = assembly.GetType("DelegatesSampleApplication.Program");
Type delegateType = assembly.GetType("DelegatesSampleApplication.IsPromotable");
// Convert the Arg1 argument to a method
MethodInfo mi = prog.GetMethod("EnableToPromote",
BindingFlags.Public | BindingFlags.Static);
// Create a delegate object that wraps the static method
validationDelegate = Delegate.CreateDelegate(delegateType, mi);
}
catch (ArgumentException)
{
Console.WriteLine("Phew... not working" );
return;
}
答案 1 :(得分：1)
它现在运行正常所以这里是完整的代码，我只做了2次更改 -
1＆GT;员工列表是一个对象列表，因此它生成了一个不匹配错误，因为PromoteEmployee需要一个类型列表 - Employee。 我改变了它，所以它现在是通用的。
2 - ;我上面提到的建议，使用Delegate.CreateDelegate
Console.WriteLine("***************Loading External assembly*************");
Assembly assembly = Assembly.LoadFrom(@"CXXXXXX\ClassLibrary1\bin\Debug\ClassLibrary1.dll");
Type employeeType = assembly.GetType("DelegatesSampleApplication.Employee"); //Gets the System.Type object for the Employee Class from the just loaded assembly with all it's dependencies
object employeeInstance = Activator.CreateInstance(employeeType);//Create an instance of the Employee Class Type
Console.WriteLine("***************Loading External assembly properties*************");
PropertyInfo[] propertyInfoColl = employeeType.GetProperties();
foreach(var item in propertyInfoColl)
{
Console.WriteLine("Loaded Type Property Name {0} and default value {1}", item.Name, item.GetValue(employeeInstance, null));
}
Console.WriteLine("***************Setting External assembly propeties for the first instance*************");
PropertyInfo employeeId = (PropertyInfo)employeeType.GetProperty("EmployeeId");
employeeId.SetValue(employeeInstance, 1);
Console.WriteLine("Employee Id Property value now set to " + employeeId.GetValue(employeeInstance,null));
PropertyInfo employeeName = (PropertyInfo)employeeType.GetProperty("EmployeeName");
employeeName.SetValue(employeeInstance, "A");
Console.WriteLine("Employee Name Property value now set to " + employeeName.GetValue(employeeInstance, null));
PropertyInfo salary = (PropertyInfo)employeeType.GetProperty("Salary");
salary.SetValue(employeeInstance, 40000);
Console.WriteLine("Salary Property value now set to " + salary.GetValue(employeeInstance, null));
PropertyInfo experience = (PropertyInfo)employeeType.GetProperty("Experience");
experience.SetValue(employeeInstance, 3);
Console.WriteLine("Experience Property value now set to " + experience.GetValue(employeeInstance, null));
Console.WriteLine("***************Setting External assembly propeties for the second instance*************");
object employeeInstance2 = Activator.CreateInstance(employeeType);
PropertyInfo employeeId2 = (PropertyInfo)employeeType.GetProperty("EmployeeId");
employeeId2.SetValue(employeeInstance2, 2);
Console.WriteLine("Employee Id Property value now set to " + employeeId2.GetValue(employeeInstance2, null));
PropertyInfo employeeName2 = (PropertyInfo)employeeType.GetProperty("EmployeeName");
employeeName2.SetValue(employeeInstance2, "B");
Console.WriteLine("Employee Name Property value now set to " + employeeName2.GetValue(employeeInstance2, null));
PropertyInfo salary2 = (PropertyInfo)employeeType.GetProperty("Salary");
salary2.SetValue(employeeInstance2, 50000);
Console.WriteLine("Salary Property value now set to " + salary2.GetValue(employeeInstance2, null));
PropertyInfo experience2 = (PropertyInfo)employeeType.GetProperty("Experience");
experience2.SetValue(employeeInstance2, 6);
Console.WriteLine("Experience Property value now set to " + experience2.GetValue(employeeInstance2, null));
Console.WriteLine("***************Creating an array list that will hold these employee instances***************");
/// list creation goes here
var listType = typeof(List<>);
var constructedListType = listType.MakeGenericType(employeeType);
var employeeInstanceListType = Activator.CreateInstance(constructedListType);
var employeeInstanceListInstance = (IList)Activator.CreateInstance(constructedListType);
employeeInstanceListInstance.Add(employeeInstance);
employeeInstanceListInstance.Add(employeeInstance2);
Console.WriteLine("***************Invoking External assembly methods*************");
//var agrsDel = new Object[] {(employeeInstance) => return employeeInstance};
Delegate validationDelegate;
try
{
Type prog = assembly.GetType("DelegatesSampleApplication.Program");
Type delegateType = assembly.GetType("DelegatesSampleApplication.IsPromotable");
// Convert the Arg1 argument to a method
MethodInfo mi = prog.GetMethod("EnableToPromote",
BindingFlags.Public | BindingFlags.Static);
// Create a delegate object that wraps the static method
validationDelegate = Delegate.CreateDelegate(delegateType, mi);
}
catch (ArgumentException)
{
Console.WriteLine("Phew... not working" );
return;
}
dynamic value = employeeType.InvokeMember("PromoteEmployees", BindingFlags.InvokeMethod | BindingFlags.Instance | BindingFlags.Public, null, employeeInstance, new Object[] { employeeInstanceListInstance, validationDelegate });