Question

我收到任何人可以帮助我的错误。我使用带有linq到sql的dotnet框架4 下面是堆栈跟踪

No parameterless constructor defined for this object.

描述：执行当前Web请求期间发生了未处理的异常。请查看堆栈跟踪以获取有关错误及其源自代码的位置的更多信息。

异常详细信息：System.MissingMethodException：没有为此对象定义无参数构造函数。

来源错误：

在执行当前Web请求期间生成了未处理的异常。可以使用下面的异常堆栈跟踪来识别有关异常的起源和位置的信息。

堆栈追踪：

 [MissingMethodException: No parameterless constructor defined for this object.]
   System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck) +0
   System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark) +113
   System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark) +232
   System.Activator.CreateInstance(Type type, Boolean nonPublic) +83
   System.Activator.CreateInstance(Type type) +6
   System.Web.HttpRuntime.FastCreatePublicInstance(Type type) +78
   System.Web.UI.WebControls.LinqDataSourceView.CreateContext(Type contextType) +6
       System.Web.UI.WebControls.LinqDataSourceView.CreateContextAndTable(DataSourceOperation operation) +799
   System.Web.UI.WebControls.LinqDataSourceView.CreateContextAndTableForSelect() +137
   System.Web.UI.WebControls.LinqDataSourceView.CreateContext(DataSourceOperation operation) +12
   System.Web.UI.WebControls.ContextDataSourceView.GetSource(QueryContext context) +20
   System.Web.UI.WebControls.LinqDataSourceView.GetSource(QueryContext context) +325
   System.Web.UI.WebControls.LinqDataSourceView.ExecuteSelect(DataSourceSelectArguments arguments) +63
   System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) +21
   System.Web.UI.WebControls.DataBoundControl.PerformSelect() +138
   System.Web.UI.WebControls.BaseDataBoundControl.DataBind() +30
   System.Web.UI.WebControls.GridView.DataBind() +4
   System.Web.UI.WebControls.BaseDataBoundControl.EnsureDataBound() +105
   System.Web.UI.WebControls.CompositeDataBoundControl.CreateChildControls() +75
   System.Web.UI.Control.EnsureChildControls() +83
   System.Web.UI.Control.PreRenderRecursiveInternal() +42
   System.Web.UI.Control.PreRenderRecursiveInternal() +155
   System.Web.UI.Control.PreRenderRecursiveInternal() +155
   System.Web.UI.Control.PreRenderRecursiveInternal() +155
   System.Web.UI.Control.PreRenderRecursiveInternal() +155
   System.Web.UI.Control.PreRenderRecursiveInternal() +155
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +974

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET     Version:4.0.30319.18446

Answer 1

LINQDataContext.Designer.cs文件是自动生成的，不要更改它，而是使用非参数化构造函数在单独的文件中创建部分类，例如：

public partial class MyDataContext : System.Data.Linq.DataContext
{
    public MyDataContext() 
        :base( ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString, mappingSource)
    {

    }
}

Answer 2

问题已得到解决。我只是在LINQDataContext.Designer.cs中创建一个无参数构造函数

public ChallanTemplateDataContext(): 
  base(Util.connectionStr, mappingSource)

{

  OnCreated();

}

Answer 3

错误是不言自明的。您可能已经创建了这样的类。您只需要在其中添加无参数构造函数。见下面的例子：

public class cls
{
   public cls ()
   {
   }
   // your other parameterized constructors
}

没有为此对象ASP.NET网站定义无参数构造函数

3 个答案: