从datagridview到数据库的合并查询不执行sql，vb.net

从执行合并查询时遇到问题，无法更新

DataGridView

表中的值或将其插入sql server数据库表中。下面是我的代码，它没有给我任何错误或中断，但是我最近注意到它在我的数据库表dbo.schedule中创建了完整的行，其中包含所有NULL值，甚至键位置，有人能帮我吗？我不太熟悉sql中的合并查询，因此请指出我的语法存在的问题：

Dim query As String = String.Empty


query &= "DECLARE @TaskID nvarchar(8), @Task nvarchar(50), @Start_date datetime, @Due_date datetime, @Complete bit, @Task_Manager nvarchar(8), @JRID nvarchar(10), @Entered_By char(50), @Time_Entered datetime;"
query &= "MERGE INTO schedule USING (VALUES (@TaskID, @Task, @start_date, @Due_Date, @Complete, @Task_Manager, @JRID, @Entered_By, @Time_Entered)) AS t(TaskID, Task, start_date, Due_Date, Complete, Task_Manager, JRID, Entered_By, Time_Entered) "
query &= "ON schedule.TaskID = @TaskID WHEN MATCHED THEN"
query &= " UPDATE SET schedule.TaskID = t.TaskID, schedule.Task=t.Task, schedule.start_date=t.start_date, schedule.due_date=t.due_date, schedule.complete=t.complete, schedule.task_manager=t.task_manager, "
query &= "schedule.JRID=t.JRID, schedule.Entered_by=t.Entered_by, schedule.Time_Entered=t.Time_Entered"
query &= " WHEN NOT MATCHED THEN INSERT (TaskID, Task, start_date, Due_Date, Complete, Task_Manager, JRID, Entered_By, Time_Entered)"
query &= " VALUES (@TaskID, @Task, @start_date, @Due_Date, @Complete, @Task_Manager, @JRID, @Entered_By, @Time_Entered);"


Using conn As New SqlConnection(dbLocations(0, 1))
    Using comm As New SqlCommand()
        With comm
            For Each row As DataGridViewRow In MainSchedule.DataGridView1.Rows
                If Not (row.Cells(0).Value = Nothing) Then
                    .Parameters.Clear()
                    .Connection = conn
                    .CommandType = CommandType.Text
                    .CommandText = query
                    insertcommand.Parameters.AddWithValue("@TaskID", TNn)
                    insertcommand.Parameters.AddWithValue("@Complete", "False")
                    insertcommand.Parameters.AddWithValue("@Task", row.Cells(0).Value)
                    insertcommand.Parameters.AddWithValue("@Start_date", row.Cells(1).Value)
                    insertcommand.Parameters.AddWithValue("@Due_Date", row.Cells(2).Value)
                    insertcommand.Parameters.AddWithValue("@JRID", txtJRID.Text)
                    insertcommand.Parameters.AddWithValue("@Task_Manager", row.Cells(3).Value)
                    insertcommand.Parameters.AddWithValue("@Entered_By", GetUserName())
                    insertcommand.Parameters.AddWithValue("@Time_Entered", Now)
                    NextTask()
                End If
            Next
        End With
        conn.Open()
        comm.ExecuteNonQuery()
   End Using
End Using

---

如果有人想知道，我想出来了，这是我的新代码：

    Connexion.Open()
                Dim query As String = String.Empty
                Dim keypos = 0

                query &= "UPDATE schedule SET Task = @Task, Complete = @Complete, Start_date = @Start_date, "
                query &= "Due_date = @Due_date, JRID = @JRID, Task_Manager = @Task_Manager, Entered_By = @Entered_By, Time_Entered = @Time_Entered "
                query &= "WHERE TaskID = @TaskID "
                query &= "IF @@ROWCOUNT = 0 INSERT INTO schedule ( TaskID, Task, start_date, Due_Date, Complete, Task_Manager, JRID, Entered_By, Time_Entered)"
                query &= " VALUES ( @TaskID, @Task, @start_date, @Due_Date, @Complete, @Task_Manager, @JRID, @Entered_By, @Time_Entered);"

                For Each row As DataGridViewRow In MainSchedule.DataGridView1.Rows
                    If Not (row.Cells(0).Value = Nothing) Then
                        insertcommand.Parameters.Clear()
                        insertcommand.CommandText = query
                        insertcommand.Parameters.AddWithValue("@TaskID", row.Cells(0).Value)
                        insertcommand.Parameters.AddWithValue("@Complete", "False")
                        insertcommand.Parameters.AddWithValue("@Task", row.Cells(1).Value)
                        insertcommand.Parameters.AddWithValue("@Start_date", row.Cells(2).Value)
                        insertcommand.Parameters.AddWithValue("@Due_Date", row.Cells(3).Value)
                        insertcommand.Parameters.AddWithValue("@JRID", txtJRID.Text)
                        insertcommand.Parameters.AddWithValue("@Task_Manager", row.Cells(4).Value)
                        insertcommand.Parameters.AddWithValue("@Entered_By", GetUserName())
                        insertcommand.Parameters.AddWithValue("@Time_Entered", Now)
                        insertcommand.ExecuteNonQuery()
                    End If
                    keypos = keypos + 1
                Next

                Connexion.Close()