Question

我理解异常意味着什么，我不明白的是为什么即使我提到谓词dataRow.RowState != DataRowState.Deleted，标记为删除的行也会被删除在我的＆＃39;哪里＆＃39;条款？

    //DataSet is a strongly typed dataset
    DataSet.TableB_row rowToDelete = dataSet.TableB.where(x=>x.ID==ID).First();
    rowToDelete.Delete(); 
    //don't want to use Remove(), might have to do RejectChanges depending on logic
    //I do not want to call AcceptChanges just yet.
    var results = (from rowA in dataSet.TableA
                   join rowB in dataSet.TableB
                        on rowA.ID equals rowB.ID
                   join rowC in dataSet.TableC
                        on rowB.ID equals rowC.ID
                    where rowB.RowState != DataRowState.Deleted
    //added RowState check for other tables hoping that might fix, but didn't
                        && rowA.RowState != DataRowState.Deleted
                        && rowC.RowState != DataRowState.Deleted
                        && rowA.ID == someID
                        select new { rowB.ColA, rowC.ColA });

    foreach (var result in results)
    {
       //deletedRowInaccessibleException thrown
       //some logic, not modifying the collection. Doesn't even get this far.
    }

当然我做错了什么，但无法弄明白。关于SO的类似帖子，主要建议添加RowState检查，我已经拥有。

Answer 1

在未接受更改的情况下，加入似乎会尝试评估已删除行的ID，然后使用 where 子句对其进行过滤。要解决此问题，您可以先创建“bRows”查询并在 join 中使用该查询，而不是直接使用TableB。这样的事情。

var bRows = dataset.TableB.Where(r => r.RowState != DataRowState.Delete);
var results = (from rowA in dataset.TableA
               join rowB in bRows
                    on rowA.ID equals rowB.ID
               join rowC in dataset.TableC
                    on rowB.ID equals rowC.ID
               select new { rowB.ColA, rowC.ColA });

DeletedRowInaccessibleException同时为每个人做

1 个答案: