Salve a tutti,
sto iniziando da poco a scivere in ASp.net e uso il tool free di $MS.
usando il GridView e poi il DetailsView per editare e aggiornare il record non ho problemi, ma quando voglio aggiungere un nuovo record, si visualizza tutto questo:


codice:
Server Error in '/miosito' Application.
[OleDbException (0x80004005): Impossibile assegnare il valore Null ad una variabile non di tipo Variant.]
   System.Data.OleDb.OleDbCommand.ExecuteCommandTextErrorHandling(OleDbHResult hr) +65
   System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleResult(tagDBPARAMS dbParams, Object& executeResult) +181
   System.Data.OleDb.OleDbCommand.ExecuteCommandText(Object& executeResult) +307
   System.Data.OleDb.OleDbCommand.ExecuteCommand(CommandBehavior behavior, Object& executeResult) +77
   System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior behavior, String method) +188
   System.Data.OleDb.OleDbCommand.ExecuteNonQuery() +112
   System.Web.UI.WebControls.SqlDataSourceView.ExecuteDbCommand(DbCommand command, DataSourceOperation operation) +493
   System.Web.UI.WebControls.SqlDataSourceView.ExecuteInsert(IDictionary values) +549
   System.Web.UI.DataSourceView.Insert(IDictionary values, DataSourceViewOperationCallback callback) +173
   System.Web.UI.WebControls.DetailsView.HandleInsert(String commandArg, Boolean causesValidation) +624
   System.Web.UI.WebControls.DetailsView.HandleEvent(EventArgs e, Boolean causesValidation, String validationGroup) +745
   System.Web.UI.WebControls.DetailsView.OnBubbleEvent(Object source, EventArgs e) +162
   System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +56
   System.Web.UI.WebControls.DetailsViewRow.OnBubbleEvent(Object source, EventArgs e) +117
   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) +3838