Question

我有这段代码：

Private Sub bbSaveloc_ItemClick(ByVal sender As System.Object, ByVal e As DevExpress.XtraBars.ItemClickEventArgs) Handles bbSaveloc.ItemClick
    gvLocations.CloseEditor()
    gvLocations.UpdateCurrentRow()
    'standorte speichern
    fb.Connect()
    fb.ReadyForData()
    fb.Command.Parameters.AddWithValue("@company_id", company_id)
    'evtl. vorhandene location_id-s holen
    fb.Command.CommandText = "select location_id from locations where company_id=@company_id order by location_id"
    Try
        fb.Datareader = fb.Command.ExecuteReader
    Catch ex As FirebirdSql.Data.FirebirdClient.FbException
        XtraMessageBox.Show(ex.Message, "Fehler", MessageBoxButtons.OK, MessageBoxIcon.Error)
        fb.Close()
        Exit Sub
    End Try
    Dim index As Integer = 0
    If fb.Datareader.HasRows Then
        While fb.Datareader.Read
            fb.Dataset.Tables(0).Rows(index).Item(0) = fb.Datareader.Item(0)
            index = index + 1
        End While
    End If
    'insert
    fb.Command.Parameters.Add("@location_id", FirebirdSql.Data.FirebirdClient.FbDbType.Integer, 0, "LOCATION_ID")
    fb.Command.Parameters.Add("@name", FirebirdSql.Data.FirebirdClient.FbDbType.VarChar, 50, "NAME")
    fb.Command.Parameters.Add("@postal_code", FirebirdSql.Data.FirebirdClient.FbDbType.VarChar, 10, "POSTAL_CODE")
    fb.Command.Parameters.Add("@road_nr", FirebirdSql.Data.FirebirdClient.FbDbType.VarChar, 100, "ROAD_NR")
    fb.Command.CommandText = "insert into locations values ((SELECT NEXT VALUE FOR GEN_LOCATION_ID FROM RDB$DATABASE), @company_id, @name, @postal_code, " & _
                             "@road_nr)"
    fb.Dataadapter.InsertCommand = fb.Command
    If Not savefirst Then
        'update
        fb.Command.CommandText = "update locations set name=@name, postal_code=@postal_code, road_nr=@road_nr where location_id=@location_id and company_id=@company_id"
        fb.Dataadapter.UpdateCommand = fb.Command
        'delete
        fb.Command.CommandText = "delete from locations where company_id=@company_id"
        fb.Dataadapter.DeleteCommand = fb.Command
    End If
    fb.Dataadapter.Update(fb.Dataset.Tables(0))
    savefirst = False
End Sub

我有以下问题：

我在gridview中插入一行，然后保存它 - ＆gt;好。然后我在gridview中修改了这一行的一些值，然后我保存了它 - ＆gt;该行将被删除，不会更新为例外。

我已检查此行的RowState，已对其进行了修改。所以我不会解散，为什么它会删除该行。

如果我没有初始化DeleteCommand，则更新将作为例外工作。

修改

我现在重写了代码：

'standort datasource initialisieren
fb_loc.Connect()
fb_loc.ReadyForData()
'select
fb_loc.Command.Parameters.AddWithValue("@company_id", company_id)
fb_loc.Command.CommandText = "select * from locations where company_id=@company_id"
fb_loc.Dataadapter.SelectCommand = fb_loc.Command
Try
    fb_loc.Dataadapter.Fill(fb_loc.Dataset, "locations")
Catch ex As FirebirdSql.Data.FirebirdClient.FbException
    XtraMessageBox.Show(ex.Message, "Fehler", MessageBoxButtons.OK, MessageBoxIcon.Error)
    fb_loc.Close()
    Exit Sub
End Try
gcLocations.DataSource = fb_loc.Dataset.Tables(0)
'insert
Dim insert_command As New FbCommand("insert into locations values ((SELECT NEXT VALUE FOR GEN_LOCATION_ID FROM RDB$DATABASE), @company_id, @name, @postal_code, " & _
                         "@road_nr)", fb_loc.Connection)
insert_command.Parameters.AddWithValue("@company_id", company_id)
insert_command.Parameters.Add("@location_id", FirebirdSql.Data.FirebirdClient.FbDbType.Integer, 0, "LOCATION_ID")
insert_command.Parameters.Add("@name", FirebirdSql.Data.FirebirdClient.FbDbType.VarChar, 50, "NAME")
insert_command.Parameters.Add("@postal_code", FirebirdSql.Data.FirebirdClient.FbDbType.VarChar, 10, "POSTAL_CODE")
insert_command.Parameters.Add("@road_nr", FirebirdSql.Data.FirebirdClient.FbDbType.VarChar, 100, "ROAD_NR")
fb_loc.Dataadapter.InsertCommand = insert_command
'update
Dim update_command As New FbCommand("update locations set name=@name, postal_code=@postal_code, road_nr=@road_nr where location_id=@location_id and company_id=@company_id", _
                                    fb_loc.Connection)
update_command.Parameters.AddWithValue("@company_id", company_id)
update_command.Parameters.Add("@location_id", FirebirdSql.Data.FirebirdClient.FbDbType.Integer, 0, "LOCATION_ID")
update_command.Parameters.Add("@name", FirebirdSql.Data.FirebirdClient.FbDbType.VarChar, 50, "NAME")
update_command.Parameters.Add("@postal_code", FirebirdSql.Data.FirebirdClient.FbDbType.VarChar, 10, "POSTAL_CODE")
update_command.Parameters.Add("@road_nr", FirebirdSql.Data.FirebirdClient.FbDbType.VarChar, 100, "ROAD_NR")
fb_loc.Dataadapter.UpdateCommand = update_command
'delete
Dim delete_command As New FbCommand("delete from locations where company_id=@company_id", fb_loc.Connection)
delete_command.Parameters.AddWithValue("@company_id", company_id)
fb_loc.Dataadapter.DeleteCommand = delete_command
fb_loc.Close()

然后是保存方法：

Private Sub bbSaveloc_ItemClick(ByVal sender As System.Object, ByVal e As DevExpress.XtraBars.ItemClickEventArgs) Handles bbSaveloc.ItemClick
    gvLocations.CloseEditor()
    gvLocations.UpdateCurrentRow()
    fb_loc.Dataadapter.Update(fb_loc.Dataset.Tables(0))
End Sub

插入有效，但是f。即更新不是。我得到了一个dbconcurrency异常。

我假设，我应该将生成的location_id自动增量值返回到数据集。由于缺少location_id值，因此无法执行更新。但是如何在数据表中找回这些值？

Answer 1

您正在使用一个命令进行更新和删除命令：

    'update
    fb.Command.CommandText = "update locations set name=@name, postal_code=@postal_code, road_nr=@road_nr where location_id=@location_id and company_id=@company_id"
    fb.Dataadapter.UpdateCommand = fb.Command
    'delete
    fb.Command.CommandText = "delete from locations where company_id=@company_id"
    fb.Dataadapter.DeleteCommand = fb.Command

所以最后的作业＆＃34;胜出＆＃34;，删除行动。

相反，您需要为每个操作创建不同的命令。

DataAdapter.Update触发DeleteCommand

1 个答案: