"Object reference not set to an instance of an object" Exception When Using A DetailsView Control In ASP.NET

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I ran into an exception recently when developing a website in ASP.NET which made use of a DetailsView control bound to an ADO.NET Entity Data Model as its data source (EntityDataSource). The complete exception message was:

[NullReferenceException: Object reference not set to an instance of an object.]
System.Web.UI.WebControls.EntityDataSourceView.ConvertWCProperty(IDictionary values, Dictionary`2 convertedValues, List`1 visitedProperties, PropertyDescriptor pd, ParameterCollection referenceParameters, Dictionary`2& exceptions) +35
System.Web.UI.WebControls.EntityDataSourceView.ConvertProperties(IDictionary values, PropertyDescriptorCollection propertyDescriptors, ParameterCollection referenceParameters) +216
System.Web.UI.WebControls.EntityDataSourceView.CreateEntityForInsert(EntityDataSourceWrapper entityWrapper, IDictionary values, ParameterCollection insertParameters) +49
System.Web.UI.WebControls.EntityDataSourceView.ExecuteInsert(IDictionary values) +239
System.Web.UI.DataSourceView.Insert(IDictionary values, DataSourceViewOperationCallback callback) +86
System.Web.UI.WebControls.DetailsView.HandleInsert(String commandArg, Boolean causesValidation) +274
System.Web.UI.WebControls.DetailsView.HandleEvent(EventArgs e, Boolean causesValidation, String validationGroup) +676
System.Web.UI.WebControls.DetailsView.OnBubbleEvent(Object source, EventArgs e) +95
System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +37
System.Web.UI.WebControls.DetailsViewRow.OnBubbleEvent(Object source, EventArgs e) +113
System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +37
System.Web.UI.WebControls.LinkButton.OnCommand(CommandEventArgs e) +118
System.Web.UI.WebControls.LinkButton.RaisePostBackEvent(String eventArgument) +135
System.Web.UI.WebControls.LinkButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +175
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565

The cause of the error was a TemplateField containing an ItemTemplate with a bound DropDownList. I set this up through the wizard, which had placed the name of the bound value in square brackets, as shown below:

Bind("[LinkCategories.LinkCategoryID]")

It turns out this is a known bug in ASP.NET 3.5 SP1. Removing the square brackets, as shown below, corrected the issue.

Bind("LinkCategories.LinkCategoryID")

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