To reproduce thsi simple install the Aventure works database, run blinq, go to 'ScrapReasons table, edit row 7, update....kabam!

 Any ideas???

Guess some testing needed against other databases (besides Northwind) ? 

 Row not found or changed.
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.Data.DLinq.OptimisticConcurrencyException: Row not found or changed.

Source Error:

Line 1091:      original_x.Name = x.Name;
Line 1092:      original_x.ModifiedDate = x.ModifiedDate;
Line 1093:      db.SubmitChanges();
Line 1094:      return 1;
Line 1095:    }
 

Source File: c:\blinqtest\App_Code\StaticMethods.cs    Line: 1093

Stack Trace:

[OptimisticConcurrencyException: Row not found or changed.]
   System.Data.DLinq.ChangeProcessor.ThrowOptimisticConcurrencyException(List`1 failedUpdates, Int32 totalUpdatesAttempted) +182
   System.Data.DLinq.ChangeProcessor.SubmitChanges(ConflictMode failureMode) +620
   System.Data.DLinq.DataContext.SubmitChanges(ConflictMode failureMode) +264
   System.Data.DLinq.DataContext.SubmitChanges() +25
   ScrapReason.Update(ScrapReason original_x, ScrapReason x) in c:\blinqtest\App_Code\StaticMethods.cs:1093

[TargetInvocationException: Exception has been thrown by the target of an invocation.]
   System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) +0
   System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) +72
   System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks) +358
   System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) +29
   System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters) +17
   System.Web.UI.WebControls.ObjectDataSourceView.InvokeMethod(ObjectDataSourceMethod method, Boolean disposeInstance, Object& instance) +676
   System.Web.UI.WebControls.ObjectDataSourceView.InvokeMethod(ObjectDataSourceMethod method) +60
   System.Web.UI.WebControls.ObjectDataSourceView.ExecuteUpdate(IDictionary keys, IDictionary values, IDictionary oldValues) +2319
   System.Web.UI.DataSourceView.Update(IDictionary keys, IDictionary values, IDictionary oldValues, DataSourceViewOperationCallback callback) +179
   System.Web.UI.WebControls.GridView.HandleUpdate(GridViewRow row, Int32 rowIndex, Boolean causesValidation) +1138
   System.Web.UI.WebControls.GridView.HandleEvent(EventArgs e, Boolean causesValidation, String validationGroup) +835
   System.Web.UI.WebControls.GridView.OnBubbleEvent(Object source, EventArgs e) +162
   System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +56
   System.Web.UI.WebControls.GridViewRow.OnBubbleEvent(Object source, EventArgs e) +118
   System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +56
   System.Web.UI.WebControls.LinkButton.OnCommand(CommandEventArgs e) +107
   System.Web.UI.WebControls.LinkButton.RaisePostBackEvent(String eventArgument) +175
   System.Web.UI.WebControls.LinkButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +31
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +32
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +244
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3839

This is because the ModifiedDate property is a high-precision date time field.  From the Readme:

·         Tables with columns of type DateTime with higher precision than seconds do not update correctly. Blinq creates BoundField objects for DateTime fields that do not contain precision beyond seconds, so updates with DateTime fields with high precision that participate in optimistic concurrency fail. To fix this, do one of the following:

o        Change the precision displayed by the BoundField object by setting DataFormatString="{0:o}", HtmlEncode=false, and ApplyFormatInEditMode=true.

o        Designate the DateTime field as never participating in optimistic concurrency. See "Changing a Field’s Update Mode" earlier in this document to change the update mode for this column. Use this option carefully—removing this column from participating in optimistic concurrency will allow overwrites of the value to succeed even if the database’s value has been changed.

The dateformat string solution, are there other ways to deal witht that (other than telling it to NEVER participate in optimistic concurrency)?

I mean to say, how can that be displayed to the user in a way that is less "awful" for them to look at?

Could it be tied into some sort of date/time picker control so the user never has to see that? 

EDIT:  What if a datetime stamp was used (added as a whole new field) could optimistic concurrency use that field and then all the other fields would be set to NEVER participate so you'd have the best of both worlds?