问题描述
The parameters dictionary contains a null entry for parameter 'EID' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult Index(Int32)' in 'SQLData1.Controllers.HomeController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.
Parameter name: parameters
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.ArgumentException: The parameters dictionary contains a null entry for parameter 'EID' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult Index(Int32)' in 'SQLData1.Controllers.HomeController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.
Parameter name: parameters
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:
[ArgumentException: The parameters dictionary contains a null entry for parameter 'EID' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult Index(Int32)' in 'SQLData1.Controllers.HomeController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.
Parameter name: parameters]
System.Web.Mvc.ActionDescriptor.ExtractParameterFromDictionary(ParameterInfo parameterInfo, IDictionary`2 parameters, MethodInfo methodInfo) +924472
System.Linq.WhereSelectArrayIterator`2.MoveNext() +80
System.Linq.Buffer`1..ctor(IEnumerable`1 source) +153
System.Linq.Enumerable.ToArray(IEnumerable`1 source) +106
System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +175
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +35
System.Web.Mvc.Async.<>c__DisplayClass42.<BeginInvokeSynchronousActionMethod>b__41() +34
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +60
System.Web.Mvc.Async.<>c__DisplayClass39.<BeginInvokeActionMethodWithFilters>b__33() +77
System.Web.Mvc.Async.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49() +371
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +60
System.Web.Mvc.Async.<>c__DisplayClass2a.<BeginInvokeAction>b__20() +32
System.Web.Mvc.Async.<>c__DisplayClass25.<BeginInvokeAction>b__22(IAsyncResult asyncResult) +185
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +53
System.Web.Mvc.<>c__DisplayClass1d.<BeginExecuteCore>b__18(IAsyncResult asyncResult) +24
System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +22
System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +68
System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +22
System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +53
System.Web.Mvc.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult) +39
System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +22
System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +53
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +399
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +1
我的尝试：
我试过以下：
在控制器中创建了一种索引方法：
public ActionResult索引（int EID）
{
EmployeeContext EC = new EmployeeContext（）;
员工e1 = EC.employees.Single（emp = > emp.id == EID）;
返回查看（e1）;
}
=========== ================================================== =
还创建了两个模型，如员工和员工背景：
公共类EmployeeContext：DbContext
{
public DbSet< employee>员工{get;组; }
}
[表（员工）]
公共班级员工
{
public int id {get;组; }
公共字符串名称{get;组; }
public string gender {get;组; }
public int salary {get;组; }
}
What I have tried:
I have tried following:
In controller created an index method:
public ActionResult Index(int EID)
{
EmployeeContext EC = new EmployeeContext();
Employee e1 = EC.employees.Single(emp => emp.id == EID);
return View(e1);
}
==============================================================
and also created two models like employee and employee context:
public class EmployeeContext:DbContext
{
public DbSet<employee> employees { get; set; }
}
[Table("employee")]
public class Employee
{
public int id { get; set; }
public string name { get; set; }
public string gender { get; set; }
public int salary { get; set; }
}
推荐答案
这篇关于我从数据库访问单行employee表并使用MVC在视图上显示但是我收到以下错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！