Telerik RadGrid-我在做什么错？

Question

So I get this exception from Telerik's RadGrid when using a custom DataSource but I have no idea what I am doing wrong. Any clues?

Server Error in '/' Application.

Object reference not set to an instance of an object.

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.NullReferenceException: Object reference not set to an instance of an object.

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:

[NullReferenceException: Object reference not set to an instance of an object.]

   Telerik.Web.UI.GridResolveEnumerable.GetCollectionItemType(Boolean noItemsInEnumerator, Type& collectionItemType, Object& collectionFirstObject) +101

   Telerik.Web.UI.GridResolveEnumerable.ParseProperties() +264

   Telerik.Web.UI.GridResolveEnumerable.Initialize() +29

   Telerik.Web.UI.GridResolveEnumerable.EnsureInitialized() +45

   Telerik.Web.UI.GridResolveEnumerable.get_DataTable() +36

   Telerik.Web.UI.GridEnumerableFromDataView..ctor(GridTableView owner, IEnumerable enumerable, Boolean CaseSensitive, Boolean autoGenerateColumns, GridColumnCollection presentColumns, String[] additionalField, Boolean retrieveAllFields, Boolean enableSplitHeaderText) +245

   Telerik.Web.UI.GridDataSourceHelper.CreateGridEnumerable(GridTableView owner, IEnumerable enumerable, Boolean caseSensitive, Boolean autoGenerateColumns, GridColumnCollection presentColumns, String[] additionalField, Boolean retrieveAllFields, Boolean enableSplitHeaderText) +172

   Telerik.Web.UI.GridDataSourceHelper.GetResolvedDataSource(GridTableView owner, Object dataSource, String dataMember, Boolean caseSensitive, Boolean autoGenerateColumns, GridColumnCollection presentColumns, String[] additionalField, Boolean retrieveAllFields, Boolean enableSplitHeaderText) +322

   Telerik.Web.UI.GridTableView.get_ResolvedDataSource() +257

   Telerik.Web.UI.GridTableView.CreateChildControls(IEnumerable dataSource, Boolean useDataSource) +480

   System.Web.UI.WebControls.CompositeDataBoundControl.PerformDataBinding(IEnumerable data) +67

   System.Web.UI.WebControls.DataBoundControl.OnDataSourceViewSelectCallback(IEnumerable data) +123

   System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) +33

   System.Web.UI.WebControls.DataBoundControl.PerformSelect() +138

   Telerik.Web.UI.GridTableView.PerformSelect() +38

   System.Web.UI.WebControls.BaseDataBoundControl.DataBind() +30

   Telerik.Web.UI.GridTableView.DataBind() +391

   Telerik.Web.UI.RadGrid.DataBind() +191

   Telerik.Web.UI.RadGrid.AutoDataBind(GridRebindReason rebindReason) +4251

   Telerik.Web.UI.RadGrid.OnLoad(EventArgs e) +201

   System.Web.UI.Control.LoadRecursive() +54

   System.Web.UI.Control.LoadRecursive() +145

   System.Web.UI.Control.LoadRecursive() +145

   System.Web.UI.Control.LoadRecursive() +145

   System.Web.UI.Control.LoadRecursive() +145

   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +772     

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.17929

Answer 1

This error is happening due to some kind of (probably accidental) recursion. I'd suggest the following:

1. Look for something that triggers a redraw in your redraw code.
2. Look at your call stack when it fails and see where it is entering this endless recursion.